commit abcd027897cda25292d7f56cf072348379bbfb92
Author: Christoph Hehl <christoph.hehl@iiot-factory.com>
Date:   Mon May 11 19:40:18 2026 +0200

    Initial upload opcua service

diff --git a/dependency-reduced-pom.xml b/dependency-reduced-pom.xml
new file mode 100644
index 0000000..5442aec
--- /dev/null
+++ b/dependency-reduced-pom.xml
@@ -0,0 +1,72 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>de.opcua</groupId>
+  <artifactId>opcua-gui</artifactId>
+  <version>1.0.0</version>
+  <build>
+    <resources>
+      <resource>
+        <directory>src/main/resources</directory>
+        <includes>
+          <include>**/*</include>
+        </includes>
+      </resource>
+    </resources>
+    <plugins>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>17</source>
+          <target>17</target>
+        </configuration>
+      </plugin>
+      <plugin>
+        <groupId>org.openjfx</groupId>
+        <artifactId>javafx-maven-plugin</artifactId>
+        <version>0.0.8</version>
+        <configuration>
+          <mainClass>de.opcua.app.MainApp</mainClass>
+        </configuration>
+      </plugin>
+      <plugin>
+        <artifactId>maven-shade-plugin</artifactId>
+        <version>3.5.0</version>
+        <executions>
+          <execution>
+            <phase>package</phase>
+            <goals>
+              <goal>shade</goal>
+            </goals>
+            <configuration>
+              <transformers>
+                <transformer>
+                  <mainClass>de.opcua.app.MainApp</mainClass>
+                </transformer>
+                <transformer />
+              </transformers>
+              <filters>
+                <filter>
+                  <artifact>*:*</artifact>
+                  <excludes>
+                    <exclude>META-INF/*.SF</exclude>
+                    <exclude>META-INF/*.DSA</exclude>
+                    <exclude>META-INF/*.RSA</exclude>
+                  </excludes>
+                </filter>
+              </filters>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <javafx.version>21</javafx.version>
+    <maven.compiler.target>17</maven.compiler.target>
+    <milo.version>1.1.1</milo.version>
+    <maven.compiler.source>17</maven.compiler.source>
+  </properties>
+</project>
diff --git a/main/java/de/opcua/app/MainApp.java b/main/java/de/opcua/app/MainApp.java
new file mode 100644
index 0000000..84dc71c
--- /dev/null
+++ b/main/java/de/opcua/app/MainApp.java
@@ -0,0 +1,15 @@
+package de.opcua.app;
+
+import de.opcua.app.service.AppMode;
+import javafx.application.Application;
+
+public class MainApp {
+  public static void main(String[] args) {
+    AppMode mode = AppMode.fromArgs(args);
+    if (mode == AppMode.SERVICE) {
+      ServiceMain.run(args);
+      return;
+    }
+    Application.launch(UiApp.class, args);
+  }
+}
diff --git a/main/java/de/opcua/app/RestApiLauncher.java b/main/java/de/opcua/app/RestApiLauncher.java
new file mode 100644
index 0000000..2a044a8
--- /dev/null
+++ b/main/java/de/opcua/app/RestApiLauncher.java
@@ -0,0 +1,82 @@
+package de.opcua.app;
+
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.rest.OpcUaRestApi;
+import de.opcua.app.scripting.Store;
+import de.opcua.app.service.ActionService;
+
+/**
+ * Standalone REST API launcher for debugging
+ * Run with: mvn exec:java -Dexec.mainClass="de.opcua.app.RestApiLauncher"
+ */
+public class RestApiLauncher {
+    
+    public static void main(String[] args) {
+        System.out.println("═══════════════════════════════════════════");
+        System.out.println("  REST API Standalone Launcher");
+        System.out.println("═══════════════════════════════════════════");
+        System.out.println();
+        
+        try {
+            System.out.println("[1/3] Creating OPC UA Service...");
+            OpcUaService opc = new OpcUaService();
+            System.out.println("✅ OPC UA Service created");
+            
+            System.out.println();
+            System.out.println("[2/3] Creating REST API on port 8081...");
+            ActionService actionService = new ActionService(opc, new Store());
+            OpcUaRestApi api = new OpcUaRestApi(opc, 8081, actionService);
+            System.out.println("✅ REST API object created");
+            
+            System.out.println();
+            System.out.println("[3/3] Starting HTTP Server...");
+            api.start();
+            System.out.println("✅ HTTP Server started successfully!");
+            
+            System.out.println();
+            System.out.println("═══════════════════════════════════════════");
+            System.out.println("  ✅ REST API is now running!");
+            System.out.println("═══════════════════════════════════════════");
+            System.out.println();
+            System.out.println("Test with:");
+            System.out.println("  curl http://localhost:8081/");
+            System.out.println("  curl http://localhost:8081/api/status");
+            System.out.println();
+            System.out.println("Or open in browser:");
+            System.out.println("  http://localhost:8081/");
+            System.out.println();
+            System.out.println("Press Ctrl+C to stop...");
+            System.out.println("─────────────────────────────────────────");
+            
+            // Keep alive
+            Thread.sleep(Long.MAX_VALUE);
+            
+        } catch (Exception e) {
+            System.err.println();
+            System.err.println("═══════════════════════════════════════════");
+            System.err.println("  ❌ ERROR - Failed to start REST API!");
+            System.err.println("═══════════════════════════════════════════");
+            System.err.println();
+            System.err.println("Error message: " + e.getMessage());
+            System.err.println();
+            System.err.println("Stack trace:");
+            e.printStackTrace();
+            System.err.println();
+            System.err.println("Common causes:");
+            System.err.println("1. Port 8081 already in use");
+            System.err.println("   Check: lsof -i :8081");
+            System.err.println("   Or:    netstat -an | grep 8081");
+            System.err.println();
+            System.err.println("2. com.sun.net.httpserver not available");
+            System.err.println("   Make sure you're using JDK (not JRE)");
+            System.err.println("   Check: java -version");
+            System.err.println();
+            System.err.println("3. Firewall blocking port");
+            System.err.println("   Try: sudo ufw allow 8081 (Linux)");
+            System.err.println("   Or check System Preferences (macOS)");
+            System.err.println();
+            
+            System.exit(1);
+        }
+    }
+}
diff --git a/main/java/de/opcua/app/ServiceMain.java b/main/java/de/opcua/app/ServiceMain.java
new file mode 100644
index 0000000..fd3fc3f
--- /dev/null
+++ b/main/java/de/opcua/app/ServiceMain.java
@@ -0,0 +1,203 @@
+package de.opcua.app;
+
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.rest.OpcUaRestApi;
+import de.opcua.app.scripting.Store;
+import de.opcua.app.service.ActionService;
+import de.opcua.app.service.ActionPersistenceService;
+
+import java.time.Instant;
+import java.util.*;
+import java.util.concurrent.*;
+
+/**
+ * Enhanced Service Mode for Windows/Linux background operation
+ * Runs autonomously without GUI
+ */
+public final class ServiceMain {
+
+    private ServiceMain() {}
+
+    public static void run(String[] args) {
+        System.out.println("═══════════════════════════════════════════════════════════");
+        System.out.println("  OPC UA GUI - Service Mode");
+        System.out.println("  Started: " + Instant.now());
+        System.out.println("═══════════════════════════════════════════════════════════");
+
+        // Load configuration
+        SettingsService settingsService = new SettingsService();
+        Settings settings = settingsService.load();
+
+        System.out.println("[Config] Endpoint: " + settings.endpoint());
+        System.out.println("[Config] Host: " + settings.host());
+
+        // Initialize services
+        OpcUaService opc = new OpcUaService();
+        Store store = new Store();
+        ActionService actionService = new ActionService(opc, store);
+        ActionPersistenceService persistence = new ActionPersistenceService();
+
+        // Initialize REST API (adjust port as needed)
+        OpcUaRestApi restApi = new OpcUaRestApi(opc, 8081, actionService);
+        try {
+            restApi.start();
+        } catch (Exception e) {
+            System.err.println("[REST API] Failed to start: " + e.getMessage());
+        }
+
+        // Load saved actions
+        Map<String, List<NodeAction>> savedActions = persistence.loadActions();
+        if (!savedActions.isEmpty()) {
+            System.out.println("[Actions] Loading " + savedActions.size() + " saved node configurations...");
+            actionService.importActionsFromList(savedActions);
+        } else {
+            System.out.println("[Actions] No saved actions found - service will monitor configured nodes");
+        }
+
+        // Auto-save every 60 seconds
+        persistence.startAutoSave(actionService, 60);
+
+        // Connect to OPC UA Server
+        System.out.println("[OPC UA] Connecting to " + settings.endpoint() + "...");
+        try {
+            opc.connect(settings.endpoint()).get(30, TimeUnit.SECONDS);
+            System.out.println("[OPC UA] ✅ Connected successfully");
+
+            // ✅ Digital Twin im Hintergrund bauen – API antwortet sofort
+            restApi.triggerDigitalTwinBuild();
+
+        } catch (Exception e) {
+            System.err.println("[OPC UA] ❌ Connection failed: " + e.getMessage());
+            System.err.println("[OPC UA] Service will continue and retry...");
+        }
+
+        // Main service loop
+        ScheduledExecutorService exec = Executors.newScheduledThreadPool(2, r -> {
+            Thread t = new Thread(r, "service-loop");
+            t.setDaemon(false);
+            return t;
+        });
+
+        // Monitor and trigger actions
+        exec.scheduleWithFixedDelay(() -> {
+            try {
+                if (!opc.isConnected()) {
+                    // Attempt reconnect
+                    System.out.println("[OPC UA] Not connected, attempting reconnect...");
+                    try {
+                        opc.connect(settings.endpoint()).get(10, TimeUnit.SECONDS);
+                        System.out.println("[OPC UA] ✅ Reconnected");
+
+                        // ✅ Digital Twin nach Reconnect neu bauen
+                        restApi.triggerDigitalTwinBuild();
+
+                    } catch (Exception e) {
+                        System.err.println("[OPC UA] Reconnect failed: " + e.getMessage());
+                        return;
+                    }
+                }
+
+                // Process all configured actions
+                Map<String, List<NodeAction>> allActions = actionService.getAllActions();
+                if (allActions.isEmpty()) {
+                    return;
+                }
+
+                for (Map.Entry<String, List<NodeAction>> entry : allActions.entrySet()) {
+                    String nodeId = entry.getKey();
+
+                    try {
+                        // Read current value
+                        String value = opc.readValue(nodeId).get(5, TimeUnit.SECONDS);
+
+                        // Trigger actions based on value
+                        actionService.processValueChange(nodeId, value);
+
+                    } catch (Exception e) {
+                        System.err.println("[Service] Error reading " + nodeId + ": " + e.getMessage());
+                    }
+                }
+
+            } catch (Exception e) {
+                System.err.println("[Service] Loop error: " + e.getMessage());
+            }
+        }, 0, 1, TimeUnit.SECONDS);
+
+        // Heartbeat / Status logging
+        exec.scheduleWithFixedDelay(() -> {
+            try {
+                Map<String, List<NodeAction>> allActions = actionService.getAllActions();
+                int totalActions = allActions.values().stream()
+                        .mapToInt(List::size)
+                        .sum();
+
+                long enabledActions = allActions.values().stream()
+                        .flatMap(List::stream)
+                        .filter(NodeAction::isEnabled)
+                        .count();
+
+                System.out.println(
+                        "[Heartbeat] " + Instant.now() +
+                        " | Connected: " + (opc.isConnected() ? "✅" : "❌") +
+                        " | Nodes: " + allActions.size() +
+                        " | Actions: " + totalActions + " (enabled: " + enabledActions + ")"
+                );
+
+            } catch (Exception e) {
+                System.err.println("[Heartbeat] Error: " + e.getMessage());
+            }
+        }, 10, 30, TimeUnit.SECONDS);
+
+        // Shutdown hook for graceful cleanup
+        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+            System.out.println("\n[Service] Shutdown signal received");
+
+            // Save actions before exit
+            System.out.println("[Service] Saving actions...");
+            persistence.saveActions(actionService.getAllActions());
+
+            // Disconnect OPC UA
+            System.out.println("[Service] Disconnecting from OPC UA...");
+            try {
+                opc.disconnect().get(5, TimeUnit.SECONDS);
+            } catch (Exception e) {
+                System.err.println("[Service] Disconnect error: " + e.getMessage());
+            }
+
+            // Stop REST API
+            restApi.stop();
+
+            // Shutdown action service
+            System.out.println("[Service] Shutting down action service...");
+            actionService.shutdown();
+
+            // Shutdown executor
+            System.out.println("[Service] Shutting down executor...");
+            exec.shutdown();
+            try {
+                if (!exec.awaitTermination(10, TimeUnit.SECONDS)) {
+                    exec.shutdownNow();
+                }
+            } catch (InterruptedException e) {
+                exec.shutdownNow();
+            }
+
+            System.out.println("[Service] ✅ Shutdown complete");
+        }));
+
+        System.out.println("\n[Service] Service running - Press Ctrl+C to stop");
+        System.out.println("─────────────────────────────────────────────────────────────\n");
+
+        // Keep process alive
+        try {
+            new CountDownLatch(1).await();
+        } catch (InterruptedException ignored) {
+            Thread.currentThread().interrupt();
+        }
+    }
+
+
+}
diff --git a/main/java/de/opcua/app/UiApp.java b/main/java/de/opcua/app/UiApp.java
new file mode 100644
index 0000000..edbbb6a
--- /dev/null
+++ b/main/java/de/opcua/app/UiApp.java
@@ -0,0 +1,17 @@
+package de.opcua.app;
+
+import javafx.application.Application;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Scene;
+import javafx.stage.Stage;
+
+public class UiApp extends Application {
+  @Override
+  public void start(Stage stage) throws Exception {
+    FXMLLoader loader = new FXMLLoader(UiApp.class.getResource("/ui/main.fxml"));
+    Scene scene = new Scene(loader.load(), 1262, 619); // matches WinForms client size
+    stage.setTitle("OPCUA GUI Client");
+    stage.setScene(scene);
+    stage.show();
+  }
+}
diff --git a/main/java/de/opcua/app/config/Settings.java b/main/java/de/opcua/app/config/Settings.java
new file mode 100644
index 0000000..6faeca8
--- /dev/null
+++ b/main/java/de/opcua/app/config/Settings.java
@@ -0,0 +1,64 @@
+package de.opcua.app.config;
+
+import de.opcua.app.logging.ScriptLogger;
+
+/**
+ * Enhanced Settings with HTTP/HTTPS configuration
+ */
+public record Settings(
+    String endpoint,
+    String host,
+    
+    // HTTP Configuration
+    boolean httpEnabled,
+    int httpPort,
+    
+    // HTTPS Configuration
+    boolean httpsEnabled,
+    int httpsPort,
+    String keystorePath,
+    String keystorePassword,
+    String keystoreType,
+    
+    // Script Logging
+    boolean scriptLoggingEnabled,
+    String scriptLogLevel,
+    String scriptLogDirectory
+) {
+    
+    // Default constructor with sensible defaults
+    public Settings() {
+        this(
+            "opc.tcp://opcuaserver.com:48010",
+            "http://localhost:8080",
+            true,   // HTTP enabled by default
+            8081,   // HTTP port
+            false,  // HTTPS disabled by default
+            8443,   // HTTPS port
+            "",
+            "",
+            "JKS",
+            true,
+            "INFO",
+            System.getProperty("user.home") + "/.opcua-gui/logs"
+        );
+    }
+    
+    // Backward compatibility - old constructor
+    public Settings(String listener, String endpoint, String host) {
+        this(endpoint, host, true, 8081, false, 8443, "", "", "JKS",
+             true, "INFO", System.getProperty("user.home") + "/.opcua-gui/logs");
+    }
+    
+    public static Settings defaults() {
+        return new Settings();
+    }
+    
+    public ScriptLogger.Level getLogLevel() {
+        try {
+            return ScriptLogger.Level.valueOf(scriptLogLevel.toUpperCase());
+        } catch (Exception e) {
+            return ScriptLogger.Level.INFO;
+        }
+    }
+}
diff --git a/main/java/de/opcua/app/config/SettingsService.java b/main/java/de/opcua/app/config/SettingsService.java
new file mode 100644
index 0000000..3bbff29
--- /dev/null
+++ b/main/java/de/opcua/app/config/SettingsService.java
@@ -0,0 +1,102 @@
+package de.opcua.app.config;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Map;
+
+public final class SettingsService {
+  private static final Path FILE = Path.of("settings.json");
+  private final ObjectMapper om = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);
+
+  public Settings load() {
+    if (!Files.exists(FILE)) return Settings.defaults();
+    try {
+      @SuppressWarnings("unchecked")
+      Map<String, Object> m = om.readValue(Files.readString(FILE), Map.class);
+      
+      Settings defaults = Settings.defaults();
+      
+      String endpoint = (String) m.getOrDefault("Endpoint", defaults.endpoint());
+      String host = (String) m.getOrDefault("Host", defaults.host());
+      
+      // HTTP Configuration
+      boolean httpEnabled = m.containsKey("httpEnabled")
+          ? (Boolean) m.get("httpEnabled")
+          : true;
+      
+      int httpPort = 8081;
+      if (m.containsKey("httpPort")) {
+          httpPort = ((Number) m.get("httpPort")).intValue();
+      } else if (m.containsKey("httpUrl")) {
+          // Backward compatibility - extract port from httpUrl
+          try {
+              String url = (String) m.get("httpUrl");
+              if (url.contains(":")) {
+                  String portStr = url.substring(url.lastIndexOf(":") + 1).replace("/", "");
+                  httpPort = Integer.parseInt(portStr);
+              }
+          } catch (Exception e) {}
+      }
+      
+      // HTTPS Configuration
+      boolean httpsEnabled = m.containsKey("httpsEnabled")
+          ? (Boolean) m.get("httpsEnabled")
+          : defaults.httpsEnabled();
+      
+      int httpsPort = m.containsKey("httpsPort")
+          ? ((Number) m.get("httpsPort")).intValue()
+          : defaults.httpsPort();
+      
+      String keystorePath = (String) m.getOrDefault("keystorePath", defaults.keystorePath());
+      String keystorePassword = (String) m.getOrDefault("keystorePassword", defaults.keystorePassword());
+      String keystoreType = (String) m.getOrDefault("keystoreType", defaults.keystoreType());
+      
+      // Logging fields
+      boolean loggingEnabled = m.containsKey("scriptLoggingEnabled") 
+          ? (Boolean) m.get("scriptLoggingEnabled") 
+          : defaults.scriptLoggingEnabled();
+      
+      String logLevel = (String) m.getOrDefault("scriptLogLevel", defaults.scriptLogLevel());
+      String logDir = (String) m.getOrDefault("scriptLogDirectory", defaults.scriptLogDirectory());
+      
+      return new Settings(
+          endpoint, host,
+          httpEnabled, httpPort,
+          httpsEnabled, httpsPort, keystorePath, keystorePassword, keystoreType,
+          loggingEnabled, logLevel, logDir
+      );
+    } catch (Exception e) {
+      System.err.println("Error loading settings: " + e.getMessage());
+      e.printStackTrace();
+      return Settings.defaults();
+    }
+  }
+
+  public void save(Settings s) throws IOException {
+    Map<String, Object> m = new java.util.HashMap<>();
+    m.put("Endpoint", s.endpoint());
+    m.put("Host", s.host());
+    
+    // HTTP Configuration
+    m.put("httpEnabled", s.httpEnabled());
+    m.put("httpPort", s.httpPort());
+    
+    // HTTPS Configuration
+    m.put("httpsEnabled", s.httpsEnabled());
+    m.put("httpsPort", s.httpsPort());
+    m.put("keystorePath", s.keystorePath());
+    m.put("keystorePassword", s.keystorePassword());
+    m.put("keystoreType", s.keystoreType());
+    
+    // Logging
+    m.put("scriptLoggingEnabled", s.scriptLoggingEnabled());
+    m.put("scriptLogLevel", s.scriptLogLevel());
+    m.put("scriptLogDirectory", s.scriptLogDirectory());
+    
+    Files.writeString(FILE, om.writeValueAsString(m));
+  }
+}
diff --git a/main/java/de/opcua/app/logging/ScriptLogger.java b/main/java/de/opcua/app/logging/ScriptLogger.java
new file mode 100644
index 0000000..cfb02e3
--- /dev/null
+++ b/main/java/de/opcua/app/logging/ScriptLogger.java
@@ -0,0 +1,276 @@
+package de.opcua.app.logging;
+
+import java.io.*;
+import java.nio.file.*;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.zip.GZIPOutputStream;
+
+/**
+ * JavaScript execution logger with rotation and debug levels
+ */
+public class ScriptLogger {
+    
+    public enum Level {
+        DEBUG(0), INFO(1), WARN(2), ERROR(3), OFF(4);
+        
+        private final int value;
+        Level(int value) { this.value = value; }
+        public int getValue() { return value; }
+    }
+    
+    private final String logDirectory;
+    private final String logFileName;
+    private final long maxFileSize;
+    private final int maxBackupFiles;
+    private Level currentLevel;
+    private boolean enabled;
+    
+    private PrintWriter writer;
+    private long currentFileSize;
+    private final ReentrantLock lock;
+    private final DateTimeFormatter formatter;
+    
+    public ScriptLogger(String logDirectory, boolean enabled, Level level) {
+        this.logDirectory = logDirectory;
+        this.logFileName = "javascript.log";
+        this.maxFileSize = 10 * 1024 * 1024; // 10 MB
+        this.maxBackupFiles = 5;
+        this.currentLevel = level;
+        this.enabled = enabled;
+        this.lock = new ReentrantLock();
+        this.formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS");
+        
+        if (enabled) {
+            initializeLogger();
+        }
+    }
+    
+    private void initializeLogger() {
+        try {
+            Path logDir = Paths.get(logDirectory);
+            if (!Files.exists(logDir)) {
+                Files.createDirectories(logDir);
+            }
+            
+            Path logFile = Paths.get(logDirectory, logFileName);
+            if (Files.exists(logFile)) {
+                currentFileSize = Files.size(logFile);
+            } else {
+                currentFileSize = 0;
+            }
+            
+            writer = new PrintWriter(new BufferedWriter(
+                new FileWriter(logFile.toFile(), true)), true);
+            
+            log(Level.INFO, "JavaScript logger initialized");
+            
+        } catch (IOException e) {
+            System.err.println("[ScriptLogger] Failed to initialize: " + e.getMessage());
+            enabled = false;
+        }
+    }
+    
+    public void setEnabled(boolean enabled) {
+        lock.lock();
+        try {
+            if (enabled && !this.enabled) {
+                initializeLogger();
+            } else if (!enabled && this.enabled) {
+                closeLogger();
+            }
+            this.enabled = enabled;
+        } finally {
+            lock.unlock();
+        }
+    }
+    
+    public void setLevel(Level level) {
+        this.currentLevel = level;
+    }
+    
+    public boolean isEnabled() {
+        return enabled;
+    }
+    
+    public Level getLevel() {
+        return currentLevel;
+    }
+    
+    public void debug(String message, Object... args) {
+        log(Level.DEBUG, message, args);
+    }
+    
+    public void info(String message, Object... args) {
+        log(Level.INFO, message, args);
+    }
+    
+    public void warn(String message, Object... args) {
+        log(Level.WARN, message, args);
+    }
+    
+    public void error(String message, Object... args) {
+        log(Level.ERROR, message, args);
+    }
+    
+    public void error(String message, Throwable throwable) {
+        if (!shouldLog(Level.ERROR)) return;
+        
+        log(Level.ERROR, message);
+        
+        lock.lock();
+        try {
+            if (writer != null) {
+                throwable.printStackTrace(writer);
+                writer.flush();
+            }
+        } finally {
+            lock.unlock();
+        }
+    }
+    
+    private void log(Level level, String message, Object... args) {
+        if (!shouldLog(level)) return;
+        
+        String formattedMessage = args.length > 0 
+            ? String.format(message, args) 
+            : message;
+        
+        String logLine = String.format("[%s] [%s] %s%n",
+            LocalDateTime.now().format(formatter),
+            level.name(),
+            formattedMessage
+        );
+        
+        lock.lock();
+        try {
+            if (writer != null) {
+                writer.print(logLine);
+                writer.flush();
+                
+                currentFileSize += logLine.length();
+                
+                if (currentFileSize >= maxFileSize) {
+                    rotateLog();
+                }
+            }
+            
+            // Also print to console in debug mode
+            if (level == Level.DEBUG || level == Level.ERROR) {
+                System.out.print(logLine);
+            }
+            
+        } finally {
+            lock.unlock();
+        }
+    }
+    
+    private boolean shouldLog(Level level) {
+        return enabled && level.getValue() >= currentLevel.getValue();
+    }
+    
+    private void rotateLog() {
+        try {
+            closeLogger();
+            
+            Path currentLog = Paths.get(logDirectory, logFileName);
+            
+            // Delete oldest backup if exists
+            Path oldestBackup = Paths.get(logDirectory, 
+                logFileName + "." + maxBackupFiles + ".gz");
+            if (Files.exists(oldestBackup)) {
+                Files.delete(oldestBackup);
+            }
+            
+            // Shift existing backups
+            for (int i = maxBackupFiles - 1; i >= 1; i--) {
+                Path from = Paths.get(logDirectory, logFileName + "." + i + ".gz");
+                Path to = Paths.get(logDirectory, logFileName + "." + (i + 1) + ".gz");
+                if (Files.exists(from)) {
+                    Files.move(from, to, StandardCopyOption.REPLACE_EXISTING);
+                }
+            }
+            
+            // Compress and move current log to .1.gz
+            Path backupLog = Paths.get(logDirectory, logFileName + ".1.gz");
+            compressFile(currentLog, backupLog);
+            
+            // Delete original
+            Files.delete(currentLog);
+            
+            // Reinitialize
+            currentFileSize = 0;
+            writer = new PrintWriter(new BufferedWriter(
+                new FileWriter(currentLog.toFile(), true)), true);
+            
+            log(Level.INFO, "Log rotated - new file created");
+            
+        } catch (IOException e) {
+            System.err.println("[ScriptLogger] Failed to rotate log: " + e.getMessage());
+        }
+    }
+    
+    private void compressFile(Path source, Path target) throws IOException {
+        try (FileInputStream fis = new FileInputStream(source.toFile());
+             FileOutputStream fos = new FileOutputStream(target.toFile());
+             GZIPOutputStream gzipOS = new GZIPOutputStream(fos)) {
+            
+            byte[] buffer = new byte[8192];
+            int len;
+            while ((len = fis.read(buffer)) != -1) {
+                gzipOS.write(buffer, 0, len);
+            }
+        }
+    }
+    
+    private void closeLogger() {
+        if (writer != null) {
+            writer.close();
+            writer = null;
+        }
+    }
+    
+    public void close() {
+        lock.lock();
+        try {
+            closeLogger();
+        } finally {
+            lock.unlock();
+        }
+    }
+    
+    /**
+     * Log script execution with context
+     */
+    public void logScriptExecution(String actionName, String nodeId, 
+                                   String trigger, String value, 
+                                   boolean success, String result) {
+        if (!enabled) return;
+        
+        Level level = success ? Level.INFO : Level.ERROR;
+        
+        log(level, 
+            "Script: %s | Node: %s | Trigger: %s | Value: %s | Success: %s | Result: %s",
+            actionName, nodeId, trigger, value, success, result
+        );
+    }
+    
+    /**
+     * Get current log file content (last N lines)
+     */
+    public String getRecentLogs(int lines) {
+        Path logFile = Paths.get(logDirectory, logFileName);
+        if (!Files.exists(logFile)) {
+            return "No logs available";
+        }
+        
+        try {
+            java.util.List<String> allLines = Files.readAllLines(logFile);
+            int start = Math.max(0, allLines.size() - lines);
+            return String.join("\n", allLines.subList(start, allLines.size()));
+        } catch (IOException e) {
+            return "Error reading logs: " + e.getMessage();
+        }
+    }
+}
diff --git a/main/java/de/opcua/app/model/NodeAction.java b/main/java/de/opcua/app/model/NodeAction.java
new file mode 100644
index 0000000..40c3299
--- /dev/null
+++ b/main/java/de/opcua/app/model/NodeAction.java
@@ -0,0 +1,195 @@
+package de.opcua.app.model;
+
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Represents an action that can be executed when an OPC UA node value changes.
+ * Supports trigger rules plus an optional JavaScript condition that is evaluated
+ * with the selected/checked NodeIds before the main script is started.
+ */
+public class NodeAction {
+
+    public enum TriggerType {
+        ON_CHANGE,        // Execute on any value change
+        ON_TRUE,          // Execute when value becomes true/non-zero
+        ON_FALSE,         // Execute when value becomes false/zero
+        ON_EVEN,          // Execute when value is even
+        ON_ODD,           // Execute when value is odd
+        ON_VALUE,         // Execute when value equals specific value
+        ON_GREATER_THAN,  // Execute when value > threshold
+        ON_LESS_THAN,     // Execute when value < threshold
+        ON_INTERVAL       // Execute on timer interval
+    }
+
+    private String nodeId;
+    private String actionName;
+    private TriggerType triggerType;
+    private String script;             // JavaScript code to execute
+    private String triggerValue;       // For ON_VALUE, ON_GREATER_THAN, ON_LESS_THAN
+    private int intervalMs;            // For ON_INTERVAL
+    private boolean enabled;
+    private String lastValue;          // Track last value for change detection
+
+    // Extended scripting / checkbox condition support
+    private boolean conditionEnabled;
+    private String conditionScript;
+    private List<String> conditionNodeIds;
+    private Map<String, String> nodeAliases; // nodeId -> variable alias used in JavaScript
+
+    public NodeAction() {
+        this.enabled = true;
+        this.triggerType = TriggerType.ON_CHANGE;
+        this.conditionEnabled = false;
+        this.conditionScript = "";
+        this.conditionNodeIds = new ArrayList<>();
+        this.nodeAliases = new LinkedHashMap<>();
+    }
+
+    public NodeAction(String nodeId, String actionName, TriggerType triggerType, String script) {
+        this();
+        this.nodeId = nodeId;
+        this.actionName = actionName;
+        this.triggerType = triggerType;
+        this.script = script;
+    }
+
+    /**
+     * Check if this action should be triggered based on the new value.
+     * The optional JavaScript condition is evaluated later in ActionService,
+     * because it may need fresh values from additional NodeIds.
+     */
+    public boolean shouldTrigger(String newValue) {
+        if (!enabled) return false;
+
+        try {
+            switch (triggerType) {
+                case ON_CHANGE:
+                    boolean changed = !Objects.equals(lastValue, newValue);
+                    lastValue = newValue;
+                    return changed;
+
+                case ON_TRUE:
+                    return isTruthyValue(newValue);
+
+                case ON_FALSE:
+                    return !isTruthyValue(newValue);
+
+                case ON_EVEN:
+                    return isEven(newValue);
+
+                case ON_ODD:
+                    return isOdd(newValue);
+
+                case ON_VALUE:
+                    return Objects.equals(newValue, triggerValue);
+
+                case ON_GREATER_THAN:
+                    return compareNumeric(newValue, triggerValue) > 0;
+
+                case ON_LESS_THAN:
+                    return compareNumeric(newValue, triggerValue) < 0;
+
+                case ON_INTERVAL:
+                    // Interval-based triggers are handled separately
+                    return false;
+
+                default:
+                    return false;
+            }
+        } catch (Exception e) {
+            System.err.println("Error checking trigger for action " + actionName + ": " + e.getMessage());
+            return false;
+        }
+    }
+
+    private boolean isTruthyValue(String value) {
+        if (value == null || value.trim().isEmpty()) return false;
+
+        if ("true".equalsIgnoreCase(value.trim())) return true;
+        if ("false".equalsIgnoreCase(value.trim())) return false;
+
+        try {
+            double num = Double.parseDouble(value.trim());
+            return num != 0.0;
+        } catch (NumberFormatException e) {
+            return true;
+        }
+    }
+
+    private boolean isEven(String value) {
+        try {
+            long num = Long.parseLong(value.trim());
+            return num % 2 == 0;
+        } catch (NumberFormatException e) {
+            return false;
+        }
+    }
+
+    private boolean isOdd(String value) {
+        try {
+            long num = Long.parseLong(value.trim());
+            return num % 2 != 0;
+        } catch (NumberFormatException e) {
+            return false;
+        }
+    }
+
+    private int compareNumeric(String value1, String value2) {
+        try {
+            double num1 = Double.parseDouble(value1.trim());
+            double num2 = Double.parseDouble(value2.trim());
+            return Double.compare(num1, num2);
+        } catch (NumberFormatException e) {
+            return value1.compareTo(value2);
+        }
+    }
+
+    public String getNodeId() { return nodeId; }
+    public void setNodeId(String nodeId) { this.nodeId = nodeId; }
+
+    public String getActionName() { return actionName; }
+    public void setActionName(String actionName) { this.actionName = actionName; }
+
+    public TriggerType getTriggerType() { return triggerType; }
+    public void setTriggerType(TriggerType triggerType) { this.triggerType = triggerType; }
+
+    public String getScript() { return script; }
+    public void setScript(String script) { this.script = script; }
+
+    public String getTriggerValue() { return triggerValue; }
+    public void setTriggerValue(String triggerValue) { this.triggerValue = triggerValue; }
+
+    public int getIntervalMs() { return intervalMs; }
+    public void setIntervalMs(int intervalMs) { this.intervalMs = intervalMs; }
+
+    public boolean isEnabled() { return enabled; }
+    public void setEnabled(boolean enabled) { this.enabled = enabled; }
+
+    public String getLastValue() { return lastValue; }
+    public void setLastValue(String lastValue) { this.lastValue = lastValue; }
+
+    public boolean isConditionEnabled() { return conditionEnabled; }
+    public void setConditionEnabled(boolean conditionEnabled) { this.conditionEnabled = conditionEnabled; }
+
+    public String getConditionScript() { return conditionScript; }
+    public void setConditionScript(String conditionScript) { this.conditionScript = conditionScript; }
+
+    public List<String> getConditionNodeIds() { return conditionNodeIds; }
+    public void setConditionNodeIds(List<String> conditionNodeIds) {
+        this.conditionNodeIds = conditionNodeIds != null ? new ArrayList<>(conditionNodeIds) : new ArrayList<>();
+    }
+
+    public Map<String, String> getNodeAliases() { return nodeAliases; }
+    public void setNodeAliases(Map<String, String> nodeAliases) {
+        this.nodeAliases = nodeAliases != null ? new LinkedHashMap<>(nodeAliases) : new LinkedHashMap<>();
+    }
+
+    @Override
+    public String toString() {
+        return actionName + " (" + triggerType + ")";
+    }
+}
diff --git a/main/java/de/opcua/app/model/NodeRow.java b/main/java/de/opcua/app/model/NodeRow.java
new file mode 100644
index 0000000..8f8aef9
--- /dev/null
+++ b/main/java/de/opcua/app/model/NodeRow.java
@@ -0,0 +1,75 @@
+package de.opcua.app.model;
+
+import javafx.beans.property.*;
+
+public class NodeRow {
+
+    private final BooleanProperty selected = new SimpleBooleanProperty(false);
+    private final StringProperty displayName = new SimpleStringProperty("");
+    private final StringProperty nodeType = new SimpleStringProperty("");
+    private final StringProperty nodeId = new SimpleStringProperty("");
+    private final StringProperty namespaceIndex = new SimpleStringProperty("");
+    private final StringProperty identifierType = new SimpleStringProperty("");
+    private final StringProperty value = new SimpleStringProperty("");
+
+    public NodeRow() {}
+
+    public NodeRow(
+            boolean selected,
+            String displayName,
+            String nodeType,
+            String nodeId,
+            String namespaceIndex,
+            String identifierType,
+            String value
+    ) {
+        this.selected.set(selected);
+        this.displayName.set(displayName);
+        this.nodeType.set(nodeType);
+        this.nodeId.set(nodeId);
+        this.namespaceIndex.set(namespaceIndex);
+        this.identifierType.set(identifierType);
+        this.value.set(value);
+    }
+
+    // --- Properties ------------------------------------------------
+
+    public BooleanProperty selectedProperty() { return selected; }
+    public StringProperty displayNameProperty() { return displayName; }
+    public StringProperty nodeTypeProperty() { return nodeType; }
+    public StringProperty nodeIdProperty() { return nodeId; }
+    public StringProperty namespaceIndexProperty() { return namespaceIndex; }
+    public StringProperty identifierTypeProperty() { return identifierType; }
+    public StringProperty valueProperty() { return value; }
+
+    // --- Convenience ----------------------------------------------
+
+    public boolean isSelected() {
+        return selected.get();
+    }
+
+    public void setSelected(boolean v) {
+        selected.set(v);
+    }
+
+    public String getNodeId() {
+        return nodeId.get();
+    }
+    
+    public String getDisplayName() {
+        return displayName.get();
+    }
+    
+    public String getValue() {
+        return value.get();
+    }
+
+    public void setValue(String v) {
+        value.set(v);
+    }
+
+    /** 🔥 DAS IST DER FIX FÜR <err> */
+    public boolean isReadable() {
+        return "Variable".equalsIgnoreCase(nodeType.get());
+    }
+}
diff --git a/main/java/de/opcua/app/model/TreeNodeRef.java b/main/java/de/opcua/app/model/TreeNodeRef.java
new file mode 100644
index 0000000..b5440d3
--- /dev/null
+++ b/main/java/de/opcua/app/model/TreeNodeRef.java
@@ -0,0 +1,28 @@
+package de.opcua.app.model;
+
+public record TreeNodeRef(
+    String displayName,
+    String nodeId,
+    String browseName,
+    String nodeClass,
+    String dataType,
+    String accessLevel,
+    String referenceTypeId   // ← NEU: z.B. "i=35", "i=46", "i=47"
+) {
+    // Backward-compatible constructors
+    public TreeNodeRef(String displayName, String nodeId) {
+        this(displayName, nodeId, displayName, "Unknown", "Unknown", "ReadWrite", null);
+    }
+
+    // Bestehender 6-Arg-Konstruktor bleibt kompatibel
+    public TreeNodeRef(String displayName, String nodeId, String browseName,
+                       String nodeClass, String dataType, String accessLevel) {
+        this(displayName, nodeId, browseName, nodeClass, dataType, accessLevel, null);
+    }
+
+    @Override
+    public String toString() {
+        if (displayName == null || displayName.isBlank()) return nodeId;
+        return displayName;
+    }
+}
diff --git a/main/java/de/opcua/app/opc/OpcUaService.java b/main/java/de/opcua/app/opc/OpcUaService.java
new file mode 100644
index 0000000..d6e38d6
--- /dev/null
+++ b/main/java/de/opcua/app/opc/OpcUaService.java
@@ -0,0 +1,192 @@
+package de.opcua.app.opc;
+
+import de.opcua.app.model.TreeNodeRef;
+import org.eclipse.milo.opcua.sdk.client.OpcUaClient;
+import org.eclipse.milo.opcua.stack.core.Identifiers;
+import org.eclipse.milo.opcua.stack.core.types.builtin.NodeId;
+import org.eclipse.milo.opcua.stack.core.types.builtin.Variant;
+import org.eclipse.milo.opcua.stack.core.types.structured.ReferenceDescription;
+import org.eclipse.milo.opcua.stack.core.types.enumerated.TimestampsToReturn;
+
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+public final class OpcUaService {
+
+    private volatile OpcUaClient client;
+
+    // ------------------------------------------------------------
+    // CONNECTION
+    // ------------------------------------------------------------
+
+    public boolean isConnected() {
+        return client != null;
+    }
+
+    public CompletableFuture<Void> connect(String endpointUrl) {
+        try {
+            OpcUaClient c = OpcUaClient.create(endpointUrl);
+            this.client = c;
+            return c.connect().thenApply(ignored -> null);
+        } catch (Exception e) {
+            CompletableFuture<Void> failed = new CompletableFuture<>();
+            failed.completeExceptionally(e);
+            return failed;
+        }
+    }
+
+    public CompletableFuture<Void> disconnect() {
+        OpcUaClient c = client;
+        client = null;
+        if (c == null) return CompletableFuture.completedFuture(null);
+        return c.disconnect().thenApply(ignored -> null);
+    }
+
+    // ------------------------------------------------------------
+    // BROWSE — async (für GUI)
+    // ------------------------------------------------------------
+
+    public CompletableFuture<List<TreeNodeRef>> browseRoot() {
+        return browseNode(Identifiers.RootFolder);
+    }
+
+    public CompletableFuture<List<TreeNodeRef>> browse(String nodeId) {
+        return browseNode(NodeId.parse(nodeId));
+    }
+
+    private CompletableFuture<List<TreeNodeRef>> browseNode(NodeId nodeId) {
+        try {
+            List<ReferenceDescription> refs = client.getAddressSpace().browse(nodeId);
+            return CompletableFuture.completedFuture(mapRefs(refs));
+        } catch (Exception e) {
+            CompletableFuture<List<TreeNodeRef>> f = new CompletableFuture<>();
+            f.completeExceptionally(e);
+            return f;
+        }
+    }
+
+    // ------------------------------------------------------------
+    // BROWSE — synchron (nur für Digital Twin Build Thread!)
+    // ------------------------------------------------------------
+
+    public List<TreeNodeRef> browseRootSync() throws Exception {
+        return browseNodeSync(Identifiers.RootFolder);
+    }
+
+    public List<TreeNodeRef> browseSync(String nodeId) throws Exception {
+        return browseNodeSync(NodeId.parse(nodeId));
+    }
+
+    private List<TreeNodeRef> browseNodeSync(NodeId nodeId) throws Exception {
+        List<ReferenceDescription> refs = client.getAddressSpace().browse(nodeId);
+        return mapRefs(refs);
+    }
+
+    // ── shared mapping ───────────────────────────────────────────────────────
+    private List<TreeNodeRef> mapRefs(List<ReferenceDescription> refs) {
+        return refs.stream()
+                .map(r -> {
+                    String displayName = r.getDisplayName() != null
+                            ? r.getDisplayName().getText()
+                            : r.getBrowseName().getName();
+                    String nodeClass = r.getNodeClass() != null
+                            ? r.getNodeClass().name() : "Unknown";
+                    String dataType = "Unknown";
+                    try {
+                        if (r.getTypeDefinition() != null)
+                            dataType = r.getTypeDefinition().toParseableString();
+                    } catch (Exception ignored) {}
+                    String referenceTypeId = null;
+                    try {
+                        if (r.getReferenceTypeId() != null)
+                            referenceTypeId = r.getReferenceTypeId().toParseableString();
+                    } catch (Exception ignored) {}
+                    return new TreeNodeRef(
+                            displayName,
+                            r.getNodeId().toParseableString(),
+                            r.getBrowseName().getName(),
+                            nodeClass, dataType, "ReadWrite", referenceTypeId);
+                })
+                .collect(Collectors.toList());
+    }
+
+    // ------------------------------------------------------------
+    // READ VALUE — async (für GUI)
+    // ------------------------------------------------------------
+
+    public CompletableFuture<String> readValue(String nodeId) {
+        NodeId id = NodeId.parse(nodeId);
+        return client.readValue(0, TimestampsToReturn.Neither, id)
+                .thenApply(dv -> {
+                    if (dv == null || dv.getValue() == null) return "<null>";
+                    Object v = dv.getValue().getValue();
+                    return v == null ? "<null>" : v.toString();
+                });
+    }
+
+    // ------------------------------------------------------------
+    // READ VALUE — synchron (nur für Digital Twin Build Thread!)
+    // ------------------------------------------------------------
+
+    public String readValueSync(String nodeId) throws Exception {
+        NodeId id = NodeId.parse(nodeId);
+        var dv = client.readValue(0, TimestampsToReturn.Neither, id)
+                .get(5, TimeUnit.SECONDS);
+        if (dv == null || dv.getValue() == null) return "<null>";
+        Object v = dv.getValue().getValue();
+        return v == null ? "<null>" : v.toString();
+    }
+
+    // ------------------------------------------------------------
+    // WRITE VALUE
+    // ------------------------------------------------------------
+
+    public CompletableFuture<Boolean> writeValue(String nodeId, Object value) {
+        NodeId id = NodeId.parse(nodeId);
+        try {
+            Variant variant = convertToVariant(value);
+            org.eclipse.milo.opcua.stack.core.types.builtin.DataValue dataValue =
+                new org.eclipse.milo.opcua.stack.core.types.builtin.DataValue(variant);
+
+            return client.writeValue(id, dataValue)
+                    .thenApply(statusCode -> {
+                        if (statusCode != null && statusCode.isGood()) {
+                            return true;
+                        }
+                        System.err.println("Write failed for " + nodeId + ": " + statusCode);
+                        return false;
+                    })
+                    .exceptionally(ex -> {
+                        System.err.println("Write exception for " + nodeId + ": " + ex.getMessage());
+                        return false;
+                    });
+        } catch (Exception e) {
+            CompletableFuture<Boolean> failed = new CompletableFuture<>();
+            failed.completeExceptionally(e);
+            return failed;
+        }
+    }
+
+    private Variant convertToVariant(Object value) {
+        if (value == null) return new Variant(null);
+        if (value instanceof String) {
+            String str = (String) value;
+            try {
+                return str.contains(".")
+                        ? new Variant(Double.parseDouble(str))
+                        : new Variant(Integer.parseInt(str));
+            } catch (NumberFormatException e) {
+                return new Variant(str);
+            }
+        } else if (value instanceof Integer) return new Variant((Integer) value);
+        else if (value instanceof Long)      return new Variant((Long) value);
+        else if (value instanceof Double)    return new Variant((Double) value);
+        else if (value instanceof Float)     return new Variant((Float) value);
+        else if (value instanceof Boolean)   return new Variant((Boolean) value);
+        else if (value instanceof Short)     return new Variant((Short) value);
+        else if (value instanceof Byte)      return new Variant((Byte) value);
+        return new Variant(value.toString());
+    }
+}
\ No newline at end of file
diff --git a/main/java/de/opcua/app/rest/HelpPageHandler.java b/main/java/de/opcua/app/rest/HelpPageHandler.java
new file mode 100644
index 0000000..9e187c5
--- /dev/null
+++ b/main/java/de/opcua/app/rest/HelpPageHandler.java
@@ -0,0 +1,537 @@
+package de.opcua.app.rest;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import java.io.IOException;
+
+public class HelpPageHandler implements HttpHandler {
+    
+    @Override
+    public void handle(HttpExchange exchange) throws IOException {
+        String path = exchange.getRequestURI().getPath();
+        String query = exchange.getRequestURI().getQuery();
+        
+        // Determine language from query parameter or Accept-Language header
+        String lang = "en"; // default
+        if (query != null && query.contains("lang=de")) {
+            lang = "de";
+        } else if (query != null && query.contains("lang=en")) {
+            lang = "en";
+        } else {
+            String acceptLang = exchange.getRequestHeaders().getFirst("Accept-Language");
+            if (acceptLang != null && acceptLang.toLowerCase().startsWith("de")) {
+                lang = "de";
+            }
+        }
+        
+        String html = buildHelpPage(lang);
+        byte[] bytes = html.getBytes("UTF-8");
+        
+        exchange.getResponseHeaders().set("Content-Type", "text/html; charset=UTF-8");
+        exchange.sendResponseHeaders(200, bytes.length);
+        exchange.getResponseBody().write(bytes);
+        exchange.getResponseBody().close();
+    }
+    
+    private String buildHelpPage(String lang) {
+        if ("de".equals(lang)) {
+            return buildGermanHelp();
+        } else {
+            return buildEnglishHelp();
+        }
+    }
+    
+    private String buildEnglishHelp() {
+        return "<!DOCTYPE html>" +
+"<html lang=\"en\">" +
+"<head>" +
+"<meta charset=\"UTF-8\">" +
+"<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">" +
+"<title>OPC UA API Documentation</title>" +
+"<style>" +
+":root{--bg:#fff;--text:#1c1c1e;--border:#e5e5ea;--code-bg:#f5f5f7;--blue:#007aff;--green:#34c759;--orange:#ff9500}" +
+"@media(prefers-color-scheme:dark){:root{--bg:#000;--text:#fff;--border:#38383a;--code-bg:#1c1c1e}}" +
+"*{margin:0;padding:0;box-sizing:border-box}" +
+"body{font-family:-apple-system,BlinkMacSystemFont,'SF Pro Text',Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.6;padding:20px}" +
+".container{max-width:1200px;margin:0 auto}" +
+"header{border-bottom:2px solid var(--blue);padding-bottom:20px;margin-bottom:40px}" +
+"h1{font-size:32px;font-weight:700;margin-bottom:10px}" +
+".lang-switch{float:right}" +
+".lang-switch a{color:var(--blue);text-decoration:none;margin:0 5px}" +
+"h2{font-size:24px;font-weight:600;margin:30px 0 15px;color:var(--blue)}" +
+"h3{font-size:18px;font-weight:600;margin:20px 0 10px}" +
+".endpoint{background:var(--code-bg);padding:15px;border-radius:8px;margin:15px 0;border-left:4px solid var(--blue)}" +
+".method{display:inline-block;padding:4px 8px;border-radius:4px;font-weight:600;font-size:12px;margin-right:10px}" +
+".method.get{background:var(--green);color:#fff}" +
+".method.post{background:var(--orange);color:#fff}" +
+"pre{background:var(--code-bg);padding:15px;border-radius:8px;overflow-x:auto;margin:10px 0}" +
+"code{font-family:'SF Mono',Monaco,'Courier New',monospace;font-size:14px}" +
+".note{background:#fff3cd;border-left:4px solid var(--orange);padding:15px;margin:15px 0;border-radius:4px}" +
+"table{width:100%;border-collapse:collapse;margin:15px 0}" +
+"th,td{padding:12px;text-align:left;border-bottom:1px solid var(--border)}" +
+"th{font-weight:600;background:var(--code-bg)}" +
+".toc{background:var(--code-bg);padding:20px;border-radius:8px;margin:20px 0}" +
+".toc ul{list-style:none;padding-left:0}" +
+".toc li{margin:8px 0}" +
+".toc a{color:var(--blue);text-decoration:none}" +
+"</style>" +
+"</head>" +
+"<body>" +
+"<div class=\"container\">" +
+"<header>" +
+"<div class=\"lang-switch\">" +
+"<a href=\"?lang=en\">English</a> | <a href=\"?lang=de\">Deutsch</a>" +
+"</div>" +
+"<h1>🔧 OPC UA REST API Documentation</h1>" +
+"<p>Complete reference for integrating with the OPC UA HTTP API</p>" +
+"</header>" +
+
+"<div class=\"toc\">" +
+"<h2>Table of Contents</h2>" +
+"<ul>" +
+"<li><a href=\"#overview\">Overview</a></li>" +
+"<li><a href=\"#authentication\">Authentication</a></li>" +
+"<li><a href=\"#endpoints\">API Endpoints</a></li>" +
+"<li><a href=\"#integration\">3rd Party Integration</a></li>" +
+"<li><a href=\"#examples\">Complete Examples</a></li>" +
+"<li><a href=\"#errors\">Error Handling</a></li>" +
+"</ul>" +
+"</div>" +
+
+"<h2 id=\"overview\">Overview</h2>" +
+"<p>The OPC UA HTTP API provides RESTful access to OPC UA server data. All endpoints accept and return JSON.</p>" +
+"<p><strong>Base URL:</strong> <code>http://localhost:8081</code></p>" +
+"<p><strong>Content-Type:</strong> <code>application/json</code></p>" +
+
+"<h2 id=\"authentication\">Authentication</h2>" +
+"<p>Currently, no authentication is required for local access. For production deployment, use HTTPS with client certificates.</p>" +
+
+"<h2 id=\"endpoints\">API Endpoints</h2>" +
+
+"<div class=\"endpoint\">" +
+"<h3><span class=\"method get\">GET</span> /api/status</h3>" +
+"<p>Get OPC UA connection status</p>" +
+"<h4>Response:</h4>" +
+"<pre><code>{" +
+"  \"connected\": true," +
+"  \"timestamp\": 1707989123456" +
+"}</code></pre>" +
+"<h4>Example:</h4>" +
+"<pre><code>const response = await fetch('/api/status');" +
+"const data = await response.json();" +
+"console.log('Connected:', data.connected);</code></pre>" +
+"</div>" +
+
+"<div class=\"endpoint\">" +
+"<h3><span class=\"method post\">POST</span> /api/read</h3>" +
+"<p>Read a value from an OPC UA node</p>" +
+"<h4>Request Body:</h4>" +
+"<pre><code>{" +
+"  \"nodeId\": \"ns=2;s=Temperature\"" +
+"}</code></pre>" +
+"<h4>Response:</h4>" +
+"<pre><code>{" +
+"  \"success\": true," +
+"  \"value\": \"25.5\"," +
+"  \"timestamp\": 1707989123456" +
+"}</code></pre>" +
+"<h4>Example:</h4>" +
+"<pre><code>const response = await fetch('/api/read', {" +
+"  method: 'POST'," +
+"  headers: {'Content-Type': 'application/json'}," +
+"  body: JSON.stringify({nodeId: 'ns=2;s=Temperature'})" +
+"});" +
+"const data = await response.json();" +
+"console.log('Temperature:', data.value);</code></pre>" +
+"</div>" +
+
+"<div class=\"endpoint\">" +
+"<h3><span class=\"method post\">POST</span> /api/write</h3>" +
+"<p>Write a value to an OPC UA node</p>" +
+"<h4>Request Body:</h4>" +
+"<pre><code>{" +
+"  \"nodeId\": \"ns=2;s=SetPoint\"," +
+"  \"value\": \"30.0\"" +
+"}</code></pre>" +
+"<h4>Response:</h4>" +
+"<pre><code>{" +
+"  \"success\": true," +
+"  \"written\": true" +
+"}</code></pre>" +
+"<h4>Example:</h4>" +
+"<pre><code>const response = await fetch('/api/write', {" +
+"  method: 'POST'," +
+"  headers: {'Content-Type': 'application/json'}," +
+"  body: JSON.stringify({" +
+"    nodeId: 'ns=2;s=SetPoint'," +
+"    value: '30.0'" +
+"  })" +
+"});" +
+"const data = await response.json();" +
+"console.log('Write successful:', data.written);</code></pre>" +
+"</div>" +
+
+"<div class=\"endpoint\">" +
+"<h3><span class=\"method post\">POST</span> /api/browse</h3>" +
+"<p>Browse OPC UA node hierarchy</p>" +
+"<h4>Request Body:</h4>" +
+"<pre><code>{" +
+"  \"nodeId\": \"ns=2;s=Folder\" // Optional, omit for root" +
+"}</code></pre>" +
+"<h4>Response:</h4>" +
+"<pre><code>{" +
+"  \"success\": true," +
+"  \"children\": [" +
+"    {" +
+"      \"displayName\": \"Temperature\"," +
+"      \"nodeId\": \"ns=2;s=Temperature\"" +
+"    }" +
+"  ]" +
+"}</code></pre>" +
+"</div>" +
+
+"<div class=\"endpoint\">" +
+"<h3><span class=\"method post\">POST</span> /api/browse-full</h3>" +
+"<p>Browse complete OPC UA tree (server-side recursive)</p>" +
+"<h4>Request Body:</h4>" +
+"<pre><code>{" +
+"  \"maxDepth\": 5" +
+"}</code></pre>" +
+"<h4>Response:</h4>" +
+"<pre><code>{" +
+"  \"success\": true," +
+"  \"tree\": [...nested nodes...]," +
+"  \"duration\": 1234," +
+"  \"maxDepth\": 5" +
+"}</code></pre>" +
+"</div>" +
+
+"<h2 id=\"integration\">3rd Party System Integration</h2>" +
+"<p>Use the API to integrate OPC UA data with external systems.</p>" +
+
+"<h3>Example: Send data to external REST API</h3>" +
+"<pre><code>// Read from OPC UA" +
+"const opcResponse = await fetch('/api/read', {" +
+"  method: 'POST'," +
+"  headers: {'Content-Type': 'application/json'}," +
+"  body: JSON.stringify({nodeId: 'ns=2;s=Temperature'})" +
+"});" +
+"const opcData = await opcResponse.json();" +
+"\n" +
+"// Send to external system" +
+"await fetch('https://api.example.com/data', {" +
+"  method: 'POST'," +
+"  headers: {" +
+"    'Content-Type': 'application/json'," +
+"    'Authorization': 'Bearer YOUR_TOKEN'" +
+"  }," +
+"  body: JSON.stringify({" +
+"    sensor: 'temperature'," +
+"    value: opcData.value," +
+"    timestamp: new Date().toISOString()" +
+"  })" +
+"});</code></pre>" +
+
+"<h3>Example: Login Script with Session Storage</h3>" +
+"<pre><code>// Login to external system" +
+"const loginResponse = await fetch('https://api.example.com/auth/login', {" +
+"  method: 'POST'," +
+"  headers: {'Content-Type': 'application/json'}," +
+"  body: JSON.stringify({" +
+"    username: 'user'," +
+"    password: 'secret'" +
+"  })" +
+"});" +
+"const session = await loginResponse.json();" +
+"\n" +
+"// Store session for later use" +
+"store.set('externalSession', session.token);" +
+"store.set('externalExpiry', session.expiresAt);" +
+"\n" +
+"// Use in subsequent requests" +
+"const token = store.get('externalSession');" +
+"await fetch('https://api.example.com/data', {" +
+"  headers: {'Authorization': 'Bearer ' + token}" +
+"});</code></pre>" +
+
+"<h2 id=\"examples\">Complete Examples</h2>" +
+
+"<h3>Polling Loop</h3>" +
+"<pre><code>async function pollTemperature() {" +
+"  const response = await fetch('/api/read', {" +
+"    method: 'POST'," +
+"    headers: {'Content-Type': 'application/json'}," +
+"    body: JSON.stringify({nodeId: 'ns=2;s=Temperature'})" +
+"  });" +
+"  const data = await response.json();" +
+"  " +
+"  if (data.success) {" +
+"    console.log('Temperature:', data.value);" +
+"    " +
+"    // Send to external system" +
+"    await fetch('https://api.example.com/metrics', {" +
+"      method: 'POST'," +
+"      headers: {'Content-Type': 'application/json'}," +
+"      body: JSON.stringify({" +
+"        metric: 'temperature'," +
+"        value: parseFloat(data.value)" +
+"      })" +
+"    });" +
+"  }" +
+"}" +
+"\n" +
+"// Poll every 5 seconds" +
+"setInterval(pollTemperature, 5000);</code></pre>" +
+
+"<h3>Write with Validation</h3>" +
+"<pre><code>async function setSetpoint(value) {" +
+"  // Validate" +
+"  if (value < 0 || value > 100) {" +
+"    console.error('Value out of range');" +
+"    return;" +
+"  }" +
+"  " +
+"  // Write to OPC UA" +
+"  const response = await fetch('/api/write', {" +
+"    method: 'POST'," +
+"    headers: {'Content-Type': 'application/json'}," +
+"    body: JSON.stringify({" +
+"      nodeId: 'ns=2;s=SetPoint'," +
+"      value: value.toString()" +
+"    })" +
+"  });" +
+"  " +
+"  const result = await response.json();" +
+"  if (result.success && result.written) {" +
+"    console.log('Setpoint updated to', value);" +
+"  } else {" +
+"    console.error('Write failed');" +
+"  }" +
+"}</code></pre>" +
+
+"<h2 id=\"errors\">Error Handling</h2>" +
+"<h3>Error Response Format:</h3>" +
+"<pre><code>{" +
+"  \"success\": false," +
+"  \"error\": \"Error message\"" +
+"}</code></pre>" +
+
+"<h3>Common Errors:</h3>" +
+"<table>" +
+"<tr><th>Status</th><th>Error</th><th>Solution</th></tr>" +
+"<tr><td>503</td><td>OPC UA not connected</td><td>Check OPC UA connection</td></tr>" +
+"<tr><td>400</td><td>Invalid nodeId</td><td>Verify node ID format</td></tr>" +
+"<tr><td>500</td><td>Read/Write failed</td><td>Check node permissions</td></tr>" +
+"</table>" +
+
+"<div class=\"note\">" +
+"<strong>💡 Tip:</strong> Use the browser's DevTools Network tab to debug API calls and inspect responses." +
+"</div>" +
+
+"</div>" +
+"</body>" +
+"</html>";
+    }
+    
+    private String buildGermanHelp() {
+        return "<!DOCTYPE html>" +
+"<html lang=\"de\">" +
+"<head>" +
+"<meta charset=\"UTF-8\">" +
+"<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">" +
+"<title>OPC UA API Dokumentation</title>" +
+"<style>" +
+":root{--bg:#fff;--text:#1c1c1e;--border:#e5e5ea;--code-bg:#f5f5f7;--blue:#007aff;--green:#34c759;--orange:#ff9500}" +
+"@media(prefers-color-scheme:dark){:root{--bg:#000;--text:#fff;--border:#38383a;--code-bg:#1c1c1e}}" +
+"*{margin:0;padding:0;box-sizing:border-box}" +
+"body{font-family:-apple-system,BlinkMacSystemFont,'SF Pro Text',Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.6;padding:20px}" +
+".container{max-width:1200px;margin:0 auto}" +
+"header{border-bottom:2px solid var(--blue);padding-bottom:20px;margin-bottom:40px}" +
+"h1{font-size:32px;font-weight:700;margin-bottom:10px}" +
+".lang-switch{float:right}" +
+".lang-switch a{color:var(--blue);text-decoration:none;margin:0 5px}" +
+"h2{font-size:24px;font-weight:600;margin:30px 0 15px;color:var(--blue)}" +
+"h3{font-size:18px;font-weight:600;margin:20px 0 10px}" +
+".endpoint{background:var(--code-bg);padding:15px;border-radius:8px;margin:15px 0;border-left:4px solid var(--blue)}" +
+".method{display:inline-block;padding:4px 8px;border-radius:4px;font-weight:600;font-size:12px;margin-right:10px}" +
+".method.get{background:var(--green);color:#fff}" +
+".method.post{background:var(--orange);color:#fff}" +
+"pre{background:var(--code-bg);padding:15px;border-radius:8px;overflow-x:auto;margin:10px 0}" +
+"code{font-family:'SF Mono',Monaco,'Courier New',monospace;font-size:14px}" +
+".note{background:#fff3cd;border-left:4px solid var(--orange);padding:15px;margin:15px 0;border-radius:4px}" +
+"table{width:100%;border-collapse:collapse;margin:15px 0}" +
+"th,td{padding:12px;text-align:left;border-bottom:1px solid var(--border)}" +
+"th{font-weight:600;background:var(--code-bg)}" +
+".toc{background:var(--code-bg);padding:20px;border-radius:8px;margin:20px 0}" +
+".toc ul{list-style:none;padding-left:0}" +
+".toc li{margin:8px 0}" +
+".toc a{color:var(--blue);text-decoration:none}" +
+"</style>" +
+"</head>" +
+"<body>" +
+"<div class=\"container\">" +
+"<header>" +
+"<div class=\"lang-switch\">" +
+"<a href=\"?lang=en\">English</a> | <a href=\"?lang=de\">Deutsch</a>" +
+"</div>" +
+"<h1>🔧 OPC UA REST API Dokumentation</h1>" +
+"<p>Vollständige Referenz zur Integration mit der OPC UA HTTP API</p>" +
+"</header>" +
+
+"<div class=\"toc\">" +
+"<h2>Inhaltsverzeichnis</h2>" +
+"<ul>" +
+"<li><a href=\"#overview\">Übersicht</a></li>" +
+"<li><a href=\"#authentication\">Authentifizierung</a></li>" +
+"<li><a href=\"#endpoints\">API Endpunkte</a></li>" +
+"<li><a href=\"#integration\">Drittsystem Integration</a></li>" +
+"<li><a href=\"#examples\">Vollständige Beispiele</a></li>" +
+"<li><a href=\"#errors\">Fehlerbehandlung</a></li>" +
+"</ul>" +
+"</div>" +
+
+"<h2 id=\"overview\">Übersicht</h2>" +
+"<p>Die OPC UA HTTP API bietet RESTful Zugriff auf OPC UA Server Daten. Alle Endpunkte akzeptieren und liefern JSON.</p>" +
+"<p><strong>Basis-URL:</strong> <code>http://localhost:8081</code></p>" +
+"<p><strong>Content-Type:</strong> <code>application/json</code></p>" +
+
+"<h2 id=\"authentication\">Authentifizierung</h2>" +
+"<p>Aktuell ist keine Authentifizierung für lokalen Zugriff erforderlich. Für Produktionsumgebungen verwenden Sie HTTPS mit Client-Zertifikaten.</p>" +
+
+"<h2 id=\"endpoints\">API Endpunkte</h2>" +
+
+"<div class=\"endpoint\">" +
+"<h3><span class=\"method get\">GET</span> /api/status</h3>" +
+"<p>OPC UA Verbindungsstatus abfragen</p>" +
+"<h4>Antwort:</h4>" +
+"<pre><code>{" +
+"  \"connected\": true," +
+"  \"timestamp\": 1707989123456" +
+"}</code></pre>" +
+"<h4>Beispiel:</h4>" +
+"<pre><code>const response = await fetch('/api/status');" +
+"const data = await response.json();" +
+"console.log('Verbunden:', data.connected);</code></pre>" +
+"</div>" +
+
+"<div class=\"endpoint\">" +
+"<h3><span class=\"method post\">POST</span> /api/read</h3>" +
+"<p>Wert von einem OPC UA Knoten lesen</p>" +
+"<h4>Request Body:</h4>" +
+"<pre><code>{" +
+"  \"nodeId\": \"ns=2;s=Temperature\"" +
+"}</code></pre>" +
+"<h4>Antwort:</h4>" +
+"<pre><code>{" +
+"  \"success\": true," +
+"  \"value\": \"25.5\"," +
+"  \"timestamp\": 1707989123456" +
+"}</code></pre>" +
+"<h4>Beispiel:</h4>" +
+"<pre><code>const response = await fetch('/api/read', {" +
+"  method: 'POST'," +
+"  headers: {'Content-Type': 'application/json'}," +
+"  body: JSON.stringify({nodeId: 'ns=2;s=Temperature'})" +
+"});" +
+"const data = await response.json();" +
+"console.log('Temperatur:', data.value);</code></pre>" +
+"</div>" +
+
+"<div class=\"endpoint\">" +
+"<h3><span class=\"method post\">POST</span> /api/write</h3>" +
+"<p>Wert zu einem OPC UA Knoten schreiben</p>" +
+"<h4>Request Body:</h4>" +
+"<pre><code>{" +
+"  \"nodeId\": \"ns=2;s=SetPoint\"," +
+"  \"value\": \"30.0\"" +
+"}</code></pre>" +
+"<h4>Antwort:</h4>" +
+"<pre><code>{" +
+"  \"success\": true," +
+"  \"written\": true" +
+"}</code></pre>" +
+"<h4>Beispiel:</h4>" +
+"<pre><code>const response = await fetch('/api/write', {" +
+"  method: 'POST'," +
+"  headers: {'Content-Type': 'application/json'}," +
+"  body: JSON.stringify({" +
+"    nodeId: 'ns=2;s=SetPoint'," +
+"    value: '30.0'" +
+"  })" +
+"});" +
+"const data = await response.json();" +
+"console.log('Schreiben erfolgreich:', data.written);</code></pre>" +
+"</div>" +
+
+"<h2 id=\"integration\">Drittsystem Integration</h2>" +
+"<p>Verwenden Sie die API um OPC UA Daten mit externen Systemen zu integrieren.</p>" +
+
+"<h3>Beispiel: Daten an externe REST API senden</h3>" +
+"<pre><code>// Von OPC UA lesen" +
+"const opcResponse = await fetch('/api/read', {" +
+"  method: 'POST'," +
+"  headers: {'Content-Type': 'application/json'}," +
+"  body: JSON.stringify({nodeId: 'ns=2;s=Temperature'})" +
+"});" +
+"const opcData = await opcResponse.json();" +
+"\n" +
+"// An externes System senden" +
+"await fetch('https://api.example.com/data', {" +
+"  method: 'POST'," +
+"  headers: {" +
+"    'Content-Type': 'application/json'," +
+"    'Authorization': 'Bearer IHR_TOKEN'" +
+"  }," +
+"  body: JSON.stringify({" +
+"    sensor: 'temperatur'," +
+"    value: opcData.value," +
+"    timestamp: new Date().toISOString()" +
+"  })" +
+"});</code></pre>" +
+
+"<h3>Beispiel: Login Script mit Session Speicherung</h3>" +
+"<pre><code>// Bei externem System anmelden" +
+"const loginResponse = await fetch('https://api.example.com/auth/login', {" +
+"  method: 'POST'," +
+"  headers: {'Content-Type': 'application/json'}," +
+"  body: JSON.stringify({" +
+"    username: 'benutzer'," +
+"    password: 'geheim'" +
+"  })" +
+"});" +
+"const session = await loginResponse.json();" +
+"\n" +
+"// Session für spätere Verwendung speichern" +
+"store.set('externeSession', session.token);" +
+"store.set('externeAblauf', session.expiresAt);" +
+"\n" +
+"// In nachfolgenden Requests verwenden" +
+"const token = store.get('externeSession');" +
+"await fetch('https://api.example.com/data', {" +
+"  headers: {'Authorization': 'Bearer ' + token}" +
+"});</code></pre>" +
+
+"<h2 id=\"errors\">Fehlerbehandlung</h2>" +
+"<h3>Fehler-Antwort Format:</h3>" +
+"<pre><code>{" +
+"  \"success\": false," +
+"  \"error\": \"Fehlermeldung\"" +
+"}</code></pre>" +
+
+"<h3>Häufige Fehler:</h3>" +
+"<table>" +
+"<tr><th>Status</th><th>Fehler</th><th>Lösung</th></tr>" +
+"<tr><td>503</td><td>OPC UA nicht verbunden</td><td>OPC UA Verbindung prüfen</td></tr>" +
+"<tr><td>400</td><td>Ungültige nodeId</td><td>Node ID Format überprüfen</td></tr>" +
+"<tr><td>500</td><td>Lesen/Schreiben fehlgeschlagen</td><td>Node Berechtigungen prüfen</td></tr>" +
+"</table>" +
+
+"<div class=\"note\">" +
+"<strong>💡 Tipp:</strong> Verwenden Sie die Browser DevTools (Network Tab) um API Aufrufe zu debuggen und Antworten zu inspizieren." +
+"</div>" +
+
+"</div>" +
+"</body>" +
+"</html>";
+    }
+}
diff --git a/main/java/de/opcua/app/rest/OpcUaRestApi.java b/main/java/de/opcua/app/rest/OpcUaRestApi.java
new file mode 100644
index 0000000..7ba5921
--- /dev/null
+++ b/main/java/de/opcua/app/rest/OpcUaRestApi.java
@@ -0,0 +1,833 @@
+package de.opcua.app.rest;
+
+import com.sun.net.httpserver.*;
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.service.ActionService;
+import de.opcua.app.scripting.Store;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import java.io.*;
+import java.net.InetSocketAddress;
+import java.util.*;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Collectors;
+import de.opcua.app.model.TreeNodeRef;
+
+public class OpcUaRestApi {
+
+    private final OpcUaService opcService;
+    private final ObjectMapper mapper;
+    private final ActionService actionService;
+    private HttpServer server;
+    private final int port;
+
+    // ── Digital Twin Cache — NUR für Export ─────────────────────────────────
+    private volatile List<Map<String, Object>> cachedDigitalTwin = null;
+    private volatile long digitalTwinBuildTime = 0;
+    private final AtomicBoolean building = new AtomicBoolean(false);
+
+    // ── NEU: View-NodeId Cache ────────────────────────────────────────────────
+    // Wird beim Browse befüllt, damit verschachtelte Views korrekt erkannt werden.
+    // Standard OPC-UA: i=87 = ViewsFolder
+    private final Set<String> knownViewNodeIds = ConcurrentHashMap.newKeySet();
+
+    public OpcUaRestApi(OpcUaService opcService, int port) {
+        this(opcService, port, new ActionService(opcService, new Store()));
+    }
+
+    public OpcUaRestApi(OpcUaService opcService, int port, ActionService actionService) {
+        this.opcService = opcService;
+        this.port       = port;
+        this.actionService = actionService;
+        this.mapper     = new ObjectMapper();
+        // Standard-Views vorregistrieren
+        knownViewNodeIds.add("i=87"); // ViewsFolder
+        knownViewNodeIds.add("ns=0;i=87"); // ViewsFolder fully qualified
+    }
+
+    // ── Public API ───────────────────────────────────────────────────────────
+
+    public void triggerDigitalTwinBuild() {
+        if (!building.compareAndSet(false, true)) {
+            System.out.println("[Digital Twin] Build already in progress, skipping.");
+            return;
+        }
+        cachedDigitalTwin = null;
+
+        Thread t = new Thread(() -> {
+            System.out.println("[Digital Twin] Build started...");
+            long start = System.currentTimeMillis();
+            try {
+                List<Map<String, Object>> tree = browseRecursive(null, null, 0, new LinkedHashSet<>());
+                cachedDigitalTwin    = tree;
+                digitalTwinBuildTime = System.currentTimeMillis();
+                System.out.printf("[Digital Twin] ✅ Cached %d nodes in %dms%n",
+                        countNodes(tree), System.currentTimeMillis() - start);
+            } catch (Exception e) {
+                System.err.println("[Digital Twin] ❌ " + e.getMessage());
+                e.printStackTrace();
+            } finally {
+                building.set(false);
+            }
+        }, "digital-twin-builder");
+        t.setDaemon(true);
+        t.start();
+    }
+
+    public void setDigitalTwin(List<Map<String, Object>> tree) {
+        this.cachedDigitalTwin    = tree;
+        this.digitalTwinBuildTime = System.currentTimeMillis();
+    }
+
+    public void start() throws IOException {
+        server = HttpServer.create(new InetSocketAddress(port), 0);
+
+        // ── Sofort verfügbar (kein Twin nötig) ──────────────────────────────
+        server.createContext("/api/status",      new StatusHandler());
+        server.createContext("/api/health",      new HealthHandler());
+        server.createContext("/api/read",        new ReadHandler());
+        server.createContext("/api/write",       new WriteHandler());
+        server.createContext("/api/browse",      new BrowseHandler());      // ← sofort, 1 Ebene
+        server.createContext("/api/browse-tree", new BrowseTreeHandler());  // ← lazy, pro Klick
+        server.createContext("/api/actions",     new ActionsHandler());
+        server.createContext("/api/actions/delete", new DeleteActionHandler());
+        server.createContext("/api/actions/enable", new EnableActionHandler());
+        server.createContext("/api/actions/test", new TestActionHandler());
+
+        // ── Twin-abhängig ────────────────────────────────────────────────────
+        server.createContext("/api/export",      new ExportHandler());      // ← Twin als Download
+        server.createContext("/api/twin-status", new TwinStatusHandler());  // ← Build-Fortschritt
+
+        server.createContext("/help",            new HelpPageHandler());
+        server.createContext("/",                new WebInterfaceHandler());
+
+        server.setExecutor(Executors.newFixedThreadPool(10));
+        server.start();
+
+        System.out.println("[REST API] Started on port " + port);
+        System.out.println("[Web UI]   http://localhost:" + port + "/");
+    }
+
+    public void stop() {
+        if (server != null) server.stop(0);
+    }
+
+    // ── Browse helpers ───────────────────────────────────────────────────────
+
+    /**
+     * Für Export: rekursiv, sequenziell.
+     * parentNodeId wird benötigt, um View-Kinder korrekt mit "Organizes" zu markieren.
+     */
+    private List<Map<String, Object>> browseRecursive(String nodeId, String parentNodeId,
+                                                       int depth, Set<String> path)
+            throws Exception {
+        System.out.println("[Twin] depth=" + depth + " node=" + nodeId);
+
+        Set<String> currentPath = new LinkedHashSet<>(path);
+        if (nodeId != null) {
+            if (currentPath.contains(nodeId)) {
+                return new ArrayList<>();
+            }
+            currentPath.add(nodeId);
+        }
+
+        List<TreeNodeRef> children = nodeId == null
+                ? opcService.browseRootSync()
+                : opcService.browseSync(nodeId);
+
+        System.out.println("[Twin] got " + children.size() + " children");
+
+        List<Map<String, Object>> result = new ArrayList<>();
+        for (var child : children) {
+            Map<String, Object> node = new LinkedHashMap<>();
+            node.put("nodeId",        child.nodeId());
+            node.put("displayName",   child.displayName());
+            node.put("browseName",    child.browseName());
+            node.put("nodeClass",     child.nodeClass());
+
+            if ("View".equals(child.nodeClass())) {
+                knownViewNodeIds.add(child.nodeId());
+            }
+
+            node.put("referenceType", determineReferenceType(child, nodeId));
+            node.put("dataType",      child.dataType());
+            node.put("accessLevel",   child.accessLevel());
+
+            if ("Variable".equals(child.nodeClass())) {
+                try {
+                    node.put("value", opcService.readValueSync(child.nodeId()));
+                } catch (Exception e) {
+                    node.put("value", null);
+                }
+            }
+
+            if (currentPath.contains(child.nodeId())) {
+                node.put("cycle", true);
+                node.put("children", new ArrayList<>());
+            } else {
+                node.put("children", browseRecursive(child.nodeId(), nodeId, depth + 1, currentPath));
+            }
+            result.add(node);
+        }
+        return result;
+    }
+
+    // ── NEU: Referenz-Typ Ermittlung ─────────────────────────────────────────
+    /**
+     * Bestimmt den OPC-UA Referenz-Typ eines Knotens.
+     *
+     * Priorität:
+     *  1. Service liefert referenceTypeId direkt → auflösen
+     *  2. Parent ist eine View → immer "Organizes" (NodeIds.Organizes = i=35)
+     *  3. Heuristik nach nodeClass
+     *
+     * OPC-UA Standard-NodeIds:
+     *   i=35  Organizes          – View → Kinder; Ordner-Hierarchien
+     *   i=46  HasProperty        – Variable als Eigenschaft eines Objects
+     *   i=47  HasComponent       – Object/Method als Komponente eines Objects
+     */
+    private String determineReferenceType(TreeNodeRef child, String parentNodeId) {
+        // 1. Service liefert es direkt
+        if (child.referenceTypeId() != null && !child.referenceTypeId().isBlank()) {
+            return resolveReferenceTypeId(child.referenceTypeId());
+        }
+
+        // 2. Parent ist eine View → Organizes (i=35)
+        if (isViewNode(parentNodeId)) {
+            return "Organizes"; // NodeIds.Organizes = i=35
+        }
+
+        // 3. Heuristik nach nodeClass
+        String nodeClass  = child.nodeClass() != null ? child.nodeClass() : "";
+        String browseName = child.browseName() != null ? child.browseName() : "";
+
+        return switch (nodeClass) {
+            case "Variable" -> "HasProperty";    // NodeIds.HasProperty  = i=46
+            case "Object"   -> "HasComponent";   // NodeIds.HasComponent = i=47
+            case "Method"   -> "HasComponent";
+            case "View"     -> "Organizes";      // NodeIds.Organizes    = i=35
+            default -> browseName.endsWith("Type") ? "HasTypeDefinition" : "HasComponent";
+        };
+    }
+
+    /** Löst numerische OPC-UA Standard-NodeIds auf lesbare Namen auf. */
+    private String resolveReferenceTypeId(String refTypeId) {
+        String normalized = refTypeId != null && refTypeId.startsWith("ns=0;")
+                ? refTypeId.substring("ns=0;".length())
+                : refTypeId;
+        return switch (normalized) {
+            case "i=33" -> "HierarchicalReferences";
+            case "i=35" -> "Organizes";           // NodeIds.Organizes
+            case "i=36" -> "HasEventSource";
+            case "i=40" -> "HasTypeDefinition";
+            case "i=44" -> "HasEncoding";
+            case "i=45" -> "HasSubtype";
+            case "i=46" -> "HasProperty";         // NodeIds.HasProperty
+            case "i=47" -> "HasComponent";        // NodeIds.HasComponent
+            case "i=48" -> "HasNotifier";
+            default     -> refTypeId;             // unbekannte IDs direkt zurückgeben
+        };
+    }
+
+    /** Prüft, ob eine NodeId eine bekannte View ist. */
+    private boolean isViewNode(String nodeId) {
+        if (nodeId == null) return false;
+        return knownViewNodeIds.contains(nodeId);
+    }
+
+    private int countNodes(List<Map<String, Object>> tree) {
+        int count = tree.size();
+        for (var node : tree) {
+            @SuppressWarnings("unchecked")
+            var ch = (List<Map<String, Object>>) node.get("children");
+            if (ch != null) count += countNodes(ch);
+        }
+        return count;
+    }
+
+    // ════════════════════════════════════════════════════════════════════════
+    // Base Handler
+    // ════════════════════════════════════════════════════════════════════════
+
+    private abstract class BaseHandler implements HttpHandler {
+        @Override
+        public void handle(HttpExchange exchange) throws IOException {
+            exchange.getResponseHeaders().add("Access-Control-Allow-Origin",  "*");
+            exchange.getResponseHeaders().add("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
+            exchange.getResponseHeaders().add("Access-Control-Allow-Headers", "Content-Type");
+            if ("OPTIONS".equals(exchange.getRequestMethod())) {
+                exchange.sendResponseHeaders(204, -1); return;
+            }
+            try { handleRequest(exchange); }
+            catch (Exception e) { sendError(exchange, 500, "Error: " + e.getMessage()); }
+        }
+
+        protected abstract void handleRequest(HttpExchange exchange) throws Exception;
+
+        protected void sendJson(HttpExchange exchange, Object data) throws IOException {
+            byte[] bytes = mapper.writeValueAsBytes(data);
+            exchange.getResponseHeaders().set("Content-Type", "application/json");
+            exchange.sendResponseHeaders(200, bytes.length);
+            try (OutputStream os = exchange.getResponseBody()) { os.write(bytes); }
+        }
+
+        protected void sendError(HttpExchange exchange, int code, String msg) throws IOException {
+            byte[] bytes = mapper.writeValueAsBytes(Map.of("success", false, "error", msg));
+            exchange.getResponseHeaders().set("Content-Type", "application/json");
+            exchange.sendResponseHeaders(code, bytes.length);
+            try (OutputStream os = exchange.getResponseBody()) { os.write(bytes); }
+        }
+
+        protected Map<String, Object> parseBody(HttpExchange exchange) throws IOException {
+            try (InputStream is = exchange.getRequestBody()) {
+                return mapper.readValue(is, Map.class);
+            }
+        }
+    }
+
+    // ── /api/status ──────────────────────────────────────────────────────────
+    private class StatusHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            sendJson(exchange, Map.of(
+                "connected", opcService.isConnected(),
+                "timestamp", System.currentTimeMillis()
+            ));
+        }
+    }
+
+    // ── /api/health ──────────────────────────────────────────────────────────
+    private class HealthHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            sendJson(exchange, Map.of("status", "ok"));
+        }
+    }
+
+    // ── /api/read ────────────────────────────────────────────────────────────
+    private class ReadHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = (String) body.get("nodeId");
+            if (nodeId == null) { sendError(exchange, 400, "nodeId required"); return; }
+            String value = opcService.readValue(nodeId).get(5, TimeUnit.SECONDS);
+            sendJson(exchange, Map.of("success", true, "nodeId", nodeId,
+                    "value", value, "timestamp", System.currentTimeMillis()));
+        }
+    }
+
+    // ── /api/write ───────────────────────────────────────────────────────────
+    private class WriteHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = (String) body.get("nodeId");
+            Object value  = body.get("value");
+            if (nodeId == null || value == null) { sendError(exchange, 400, "nodeId and value required"); return; }
+            boolean ok = opcService.writeValue(nodeId, value).get(5, TimeUnit.SECONDS);
+            sendJson(exchange, Map.of("success", ok, "nodeId", nodeId, "written", ok));
+        }
+    }
+
+    // ── /api/browse  (eine Ebene, sofort) ────────────────────────────────────
+    private class BrowseHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = (String) body.get("nodeId");
+
+            var kids = nodeId == null
+                    ? opcService.browseRoot().get(10, TimeUnit.SECONDS)
+                    : opcService.browse(nodeId).get(10, TimeUnit.SECONDS);
+
+            List<Map<String, Object>> list = new ArrayList<>();
+            for (var c : kids) {
+                // ── NEU: View-NodeIds beim Browse registrieren ───────────────
+                if ("View".equals(c.nodeClass())) {
+                    knownViewNodeIds.add(c.nodeId());
+                }
+                Map<String, Object> m = new LinkedHashMap<>();
+                m.put("nodeId",        c.nodeId());
+                m.put("displayName",   c.displayName());
+                m.put("browseName",    c.browseName());
+                m.put("nodeClass",     c.nodeClass());
+                m.put("referenceType", determineReferenceType(c, nodeId)); // ← NEU
+                m.put("dataType",      c.dataType());
+                m.put("accessLevel",   c.accessLevel());
+                m.put("hasChildren",   true); // konservativ; Browser expandiert bei Klick
+                list.add(m);
+            }
+            sendJson(exchange, Map.of("success", true, "nodeId",
+                    nodeId != null ? nodeId : "root", "children", list));
+        }
+    }
+
+    // ── /api/browse-tree  (lazy, eine Ebene für Tree-UI) ─────────────────────
+    private class BrowseTreeHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = (String) body.get("nodeId");
+
+            var kids = nodeId == null
+                    ? opcService.browseRoot().get(10, TimeUnit.SECONDS)
+                    : opcService.browse(nodeId).get(10, TimeUnit.SECONDS);
+
+            List<Map<String, Object>> list = new ArrayList<>();
+            for (var c : kids) {
+                if ("View".equals(c.nodeClass())) {
+                    knownViewNodeIds.add(c.nodeId());
+                }
+                Map<String, Object> m = new LinkedHashMap<>();
+                m.put("nodeId",        c.nodeId());
+                m.put("displayName",   c.displayName());
+                m.put("browseName",    c.browseName());
+                m.put("nodeClass",     c.nodeClass());
+                m.put("referenceType", determineReferenceType(c, nodeId));
+                m.put("dataType",      c.dataType());
+                m.put("accessLevel",   c.accessLevel());
+                if ("Variable".equals(c.nodeClass())) {
+                    try {
+                        m.put("value", opcService.readValue(c.nodeId()).get(5, TimeUnit.SECONDS));
+                    } catch (Exception e) { m.put("value", null); }
+                }
+                list.add(m);
+            }
+            sendJson(exchange, Map.of("success", true, "children", list));
+        }
+    }
+
+    // ── /api/actions ──────────────────────────────────────────────────────────
+    private class ActionsHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if ("GET".equals(exchange.getRequestMethod())) {
+                List<Map<String, Object>> list = actionService.getAllActionsFlat().stream()
+                        .map(OpcUaRestApi.this::actionToDto)
+                        .collect(Collectors.toList());
+                sendJson(exchange, Map.of("success", true, "actions", list));
+                return;
+            }
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "GET or POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+
+            String nodeId = string(body.get("nodeId"));
+            String name = firstNonBlank(string(body.get("actionName")), string(body.get("name")));
+            String trigger = firstNonBlank(string(body.get("triggerType")), string(body.get("trigger")), "ON_CHANGE");
+            String script = string(body.get("script"));
+            if (nodeId == null || nodeId.isBlank() || name == null || name.isBlank() || script == null || script.isBlank()) {
+                sendError(exchange, 400, "nodeId, name/actionName and script required");
+                return;
+            }
+
+            NodeAction action = new NodeAction();
+            action.setNodeId(nodeId);
+            action.setActionName(name);
+            action.setTriggerType(NodeAction.TriggerType.valueOf(trigger));
+            action.setScript(script);
+            action.setTriggerValue(firstNonBlank(string(body.get("triggerValue")), string(body.get("value"))));
+            action.setIntervalMs(intValue(firstNonBlank(string(body.get("intervalMs")), string(body.get("interval"))), 1000));
+            action.setEnabled(booleanValue(body.get("enabled"), true));
+            action.setConditionEnabled(booleanValue(body.get("conditionEnabled"), false));
+            action.setConditionScript(string(body.get("conditionScript")));
+            action.setConditionNodeIds(stringList(body.get("conditionNodeIds")));
+            action.setNodeAliases(stringMap(body.get("nodeAliases")));
+
+            actionService.addAction(action);
+            sendJson(exchange, Map.of("success", true, "action", actionToDto(action)));
+        }
+    }
+
+    private class DeleteActionHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = string(body.get("nodeId"));
+            String name = firstNonBlank(string(body.get("actionName")), string(body.get("name")));
+            if (nodeId == null || name == null) { sendError(exchange, 400, "nodeId and actionName/name required"); return; }
+            actionService.removeAction(nodeId, name);
+            sendJson(exchange, Map.of("success", true));
+        }
+    }
+
+    private class EnableActionHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = string(body.get("nodeId"));
+            String name = firstNonBlank(string(body.get("actionName")), string(body.get("name")));
+            boolean enabled = booleanValue(body.get("enabled"), true);
+            if (nodeId == null || name == null) { sendError(exchange, 400, "nodeId and actionName/name required"); return; }
+            actionService.setActionEnabled(nodeId, name, enabled);
+            sendJson(exchange, Map.of("success", true, "enabled", enabled));
+        }
+    }
+
+    private class TestActionHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = string(body.get("nodeId"));
+            String name = firstNonBlank(string(body.get("actionName")), string(body.get("name")));
+            String value = firstNonBlank(string(body.get("value")), "");
+            if (nodeId == null || name == null) { sendError(exchange, 400, "nodeId and actionName/name required"); return; }
+            actionService.testAction(nodeId, name, value);
+            sendJson(exchange, Map.of("success", true, "queued", true));
+        }
+    }
+
+    private Map<String, Object> actionToDto(NodeAction action) {
+        Map<String, Object> dto = new LinkedHashMap<>();
+        dto.put("nodeId", action.getNodeId());
+        dto.put("actionName", action.getActionName());
+        dto.put("triggerType", action.getTriggerType().name());
+        dto.put("script", action.getScript());
+        dto.put("triggerValue", action.getTriggerValue());
+        dto.put("intervalMs", action.getIntervalMs());
+        dto.put("enabled", action.isEnabled());
+        dto.put("conditionEnabled", action.isConditionEnabled());
+        dto.put("conditionScript", action.getConditionScript());
+        dto.put("conditionNodeIds", action.getConditionNodeIds());
+        dto.put("nodeAliases", action.getNodeAliases());
+        return dto;
+    }
+
+    private String string(Object value) {
+        return value == null ? null : String.valueOf(value);
+    }
+
+    private String firstNonBlank(String... values) {
+        if (values == null) return null;
+        for (String value : values) {
+            if (value != null && !value.isBlank()) return value;
+        }
+        return null;
+    }
+
+    private int intValue(String value, int fallback) {
+        if (value == null || value.isBlank()) return fallback;
+        try { return Integer.parseInt(value.trim()); }
+        catch (NumberFormatException e) { return fallback; }
+    }
+
+    private boolean booleanValue(Object value, boolean fallback) {
+        if (value == null) return fallback;
+        if (value instanceof Boolean b) return b;
+        return Boolean.parseBoolean(String.valueOf(value));
+    }
+
+    private List<String> stringList(Object value) {
+        List<String> result = new ArrayList<>();
+        if (value instanceof List<?> list) {
+            for (Object item : list) {
+                if (item != null) result.add(String.valueOf(item));
+            }
+        }
+        return result;
+    }
+
+    private Map<String, String> stringMap(Object value) {
+        Map<String, String> result = new LinkedHashMap<>();
+        if (value instanceof Map<?, ?> map) {
+            for (Map.Entry<?, ?> entry : map.entrySet()) {
+                if (entry.getKey() != null && entry.getValue() != null) {
+                    result.put(String.valueOf(entry.getKey()), String.valueOf(entry.getValue()));
+                }
+            }
+        }
+        return result;
+    }
+
+    // ── /api/twin-status ─────────────────────────────────────────────────────
+    private class TwinStatusHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            sendJson(exchange, Map.of(
+                "ready",     cachedDigitalTwin != null,
+                "building",  building.get(),
+                "cacheTime", digitalTwinBuildTime,
+                "nodeCount", cachedDigitalTwin != null ? countNodes(cachedDigitalTwin) : 0
+            ));
+        }
+    }
+
+    // ── /api/export ──────────────────────────────────────────────────────────
+    private class ExportHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+
+            if (cachedDigitalTwin == null) {
+                byte[] bytes = mapper.writeValueAsBytes(Map.of(
+                    "success", false, "cached", false,
+                    "status",  "building",
+                    "message", "Digital Twin is still being built. Check /api/twin-status."
+                ));
+                exchange.getResponseHeaders().set("Content-Type", "application/json");
+                exchange.sendResponseHeaders(202, bytes.length);
+                try (OutputStream os = exchange.getResponseBody()) { os.write(bytes); }
+                return;
+            }
+
+            Map<String, Object> export = new LinkedHashMap<>();
+            export.put("timestamp",      digitalTwinBuildTime);
+            export.put("exportType",     "full");
+            export.put("nodeCount",      countNodes(cachedDigitalTwin));
+            export.put("tree",           cachedDigitalTwin);
+
+            String filename = "opcua-export-" + digitalTwinBuildTime + ".json";
+            exchange.getResponseHeaders().set("Content-Type", "application/json");
+            exchange.getResponseHeaders().set("Content-Disposition",
+                    "attachment; filename=\"" + filename + "\"");
+            byte[] bytes = mapper.writerWithDefaultPrettyPrinter().writeValueAsBytes(export);
+            exchange.sendResponseHeaders(200, bytes.length);
+            try (OutputStream os = exchange.getResponseBody()) { os.write(bytes); }
+        }
+    }
+
+    // ── /help ────────────────────────────────────────────────────────────────
+    private class HelpPageHandler implements HttpHandler {
+        @Override public void handle(HttpExchange exchange) throws IOException {
+            String html = """
+                <html><body>
+                <h1>OPC UA REST API</h1>
+                <h2>Sofort verfügbar</h2>
+                <ul>
+                  <li><b>GET  /api/status</b> – Verbindungsstatus</li>
+                  <li><b>GET  /api/health</b> – Health check</li>
+                  <li><b>POST /api/read</b>   – {"nodeId":"ns=2;s=Temp"}</li>
+                  <li><b>POST /api/write</b>  – {"nodeId":"ns=2;s=Set","value":"30"}</li>
+                  <li><b>POST /api/browse</b> – {"nodeId":"ns=2;i=1"} — eine Ebene sofort (inkl. referenceType)</li>
+                  <li><b>POST /api/browse-tree</b> – wie browse, mit Werten für Variables (inkl. referenceType)</li>
+                  <li><b>GET/POST /api/actions</b> – Actions lesen/anlegen inkl. GraalVM-Scriptbedingungen</li>
+                </ul>
+                <h2>Digital Twin (Hintergrund-Build)</h2>
+                <ul>
+                  <li><b>GET /api/twin-status</b> – Build-Fortschritt</li>
+                  <li><b>GET /api/export</b>      – Kompletter Baum als JSON-Download</li>
+                </ul>
+                </body></html>
+                """;
+            byte[] bytes = html.getBytes("UTF-8");
+            exchange.getResponseHeaders().set("Content-Type", "text/html; charset=UTF-8");
+            exchange.sendResponseHeaders(200, bytes.length);
+            exchange.getResponseBody().write(bytes);
+            exchange.getResponseBody().close();
+        }
+    }
+
+    // ── / (Web Interface) ────────────────────────────────────────────────────
+    private class WebInterfaceHandler implements HttpHandler {
+        @Override public void handle(HttpExchange exchange) throws IOException {
+            String path = exchange.getRequestURI().getPath();
+            if (!path.equals("/") && !path.equals("/index.html")) {
+                exchange.sendResponseHeaders(404, -1); return;
+            }
+            InputStream is = getClass().getResourceAsStream("/web/web-interface.html");
+            String html = is != null
+                    ? new String(is.readAllBytes(), "UTF-8")
+                    : buildHtml();
+            if (is != null) is.close();
+            byte[] bytes = html.getBytes("UTF-8");
+            exchange.getResponseHeaders().set("Content-Type", "text/html; charset=UTF-8");
+            exchange.sendResponseHeaders(200, bytes.length);
+            exchange.getResponseBody().write(bytes);
+            exchange.getResponseBody().close();
+        }
+
+        private String buildHtml() {
+            return """
+                <!DOCTYPE html>
+                <html lang="de">
+                <head>
+                  <meta charset="UTF-8">
+                  <title>OPC UA Browser</title>
+                  <style>
+                    body { font-family: Arial, sans-serif; max-width: 1200px; margin: 30px auto;
+                           padding: 20px; background: #f0f2f5; }
+                    h1 { color: #2c3e50; }
+                    #status-bar { padding: 8px 14px; border-radius: 6px; margin-bottom: 16px; font-size: 14px; }
+                    .connected    { background: #d4edda; color: #155724; }
+                    .disconnected { background: #f8d7da; color: #721c24; }
+                    #toolbar { margin-bottom: 12px; display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
+                    button { padding: 8px 16px; border: none; border-radius: 5px;
+                             cursor: pointer; font-size: 14px; }
+                    #btn-root   { background: #3498db; color: #fff; }
+                    #btn-export { background: #27ae60; color: #fff; }
+                    #twin-status { font-size: 12px; color: #888; }
+                    #tree-container { background: #fff; border-radius: 8px; padding: 16px;
+                                      box-shadow: 0 2px 6px rgba(0,0,0,.1); min-height: 300px; }
+                    ul.tree { list-style: none; padding-left: 20px; margin: 2px 0; }
+                    li.node { padding: 3px 4px; border-radius: 4px; font-size: 13px; }
+                    li.node:hover { background: #eef4fb; }
+                    .toggle { display: inline-block; width: 16px; cursor: pointer; color: #888; }
+                    .icon   { margin: 0 4px; }
+                    .val    { color: #27ae60; font-family: monospace; margin-left: 6px; }
+                    .nc     { font-size: 11px; color: #aaa; margin-left: 4px; }
+                    /* NEU: Referenz-Typ Badge */
+                    .ref    { font-size: 10px; color: #fff; background: #7f8c8d;
+                              border-radius: 3px; padding: 1px 4px; margin-left: 5px; }
+                    .ref-organizes  { background: #8e44ad; } /* View → lila */
+                    .ref-component  { background: #2980b9; } /* HasComponent → blau */
+                    .ref-property   { background: #27ae60; } /* HasProperty → grün */
+                    .loading { color: #aaa; font-style: italic; }
+                    .spinner { display: inline-block; width: 14px; height: 14px; border: 2px solid #ccc;
+                               border-top-color: #3498db; border-radius: 50%;
+                               animation: spin .7s linear infinite; vertical-align: middle; }
+                    @keyframes spin { to { transform: rotate(360deg); } }
+                  </style>
+                </head>
+                <body>
+                  <h1>🔌 OPC UA Browser</h1>
+                  <div id="status-bar" class="disconnected">Verbinde…</div>
+                  <div id="toolbar">
+                    <button id="btn-root" onclick="loadRoot()">🔄 Root laden</button>
+                    <button id="btn-export" onclick="exportTwin()">⬇ Export JSON</button>
+                    <span id="twin-status"></span>
+                  </div>
+                  <div id="tree-container"><i class="loading">Warte auf Verbindung…</i></div>
+
+                  <script>
+                    async function checkStatus() {
+                      try {
+                        const d = await (await fetch('/api/status')).json();
+                        const bar = document.getElementById('status-bar');
+                        if (d.connected) {
+                          bar.className = 'connected';
+                          bar.textContent = '✅ Verbunden';
+                          loadRoot();
+                          pollTwinStatus();
+                        } else {
+                          bar.className = 'disconnected';
+                          bar.textContent = '❌ Nicht verbunden';
+                          setTimeout(checkStatus, 3000);
+                        }
+                      } catch(e) { setTimeout(checkStatus, 3000); }
+                    }
+
+                    async function pollTwinStatus() {
+                      try {
+                        const d = await (await fetch('/api/twin-status')).json();
+                        const el = document.getElementById('twin-status');
+                        if (d.ready) {
+                          el.textContent = '✅ Export bereit (' + d.nodeCount + ' Nodes)';
+                        } else if (d.building) {
+                          el.textContent = '⏳ Export wird gebaut…';
+                          setTimeout(pollTwinStatus, 3000);
+                        } else {
+                          el.textContent = '';
+                        }
+                      } catch(e) {}
+                    }
+
+                    async function loadRoot() {
+                      const container = document.getElementById('tree-container');
+                      container.innerHTML = '<span class="spinner"></span> Lade…';
+                      try {
+                        const raw = await fetch('/api/browse-tree', {
+                          method: 'POST',
+                          headers: { 'Content-Type': 'application/json' },
+                          body: '{}'
+                        });
+                        const d = await raw.json();
+                        console.log('browse-tree response:', JSON.stringify(d));
+
+                        if (!d.success) {
+                          container.innerHTML = 'API Fehler: ' + d.error;
+                          return;
+                        }
+                        if (!d.children || d.children.length === 0) {
+                          container.innerHTML = 'Keine Nodes gefunden';
+                          return;
+                        }
+
+                        container.innerHTML = 'Nodes: ' + d.children.length;
+                        container.appendChild(buildUl(d.children));
+
+                      } catch(e) {
+                        container.innerHTML = 'Exception: ' + e.message;
+                        console.error(e);
+                      }
+                    }
+
+                    async function expand(nodeId, li) {
+                      const existing = li.querySelector('ul');
+                      if (existing) {
+                        existing.style.display = existing.style.display === 'none' ? '' : 'none';
+                        li.querySelector('.toggle').textContent =
+                          existing.style.display === 'none' ? '▶' : '▼';
+                        return;
+                      }
+                      li.querySelector('.toggle').innerHTML = '<span class="spinner"></span>';
+                      try {
+                        const d = await post('/api/browse-tree', { nodeId });
+                        const ul = buildUl(d.children, nodeId);
+                        li.appendChild(ul);
+                        li.querySelector('.toggle').textContent = '▼';
+                      } catch(e) {
+                        li.querySelector('.toggle').textContent = '!';
+                      }
+                    }
+
+                    // NEU: referenceType → CSS-Klasse + Label
+                    function refBadge(refType) {
+                      if (!refType) return '';
+                      let cls = 'ref';
+                      if (refType === 'Organizes')    cls += ' ref-organizes';
+                      else if (refType === 'HasComponent') cls += ' ref-component';
+                      else if (refType === 'HasProperty')  cls += ' ref-property';
+                      const label = refType
+                        .replace('HasComponent',   'Comp')
+                        .replace('HasProperty',    'Prop')
+                        .replace('HasTypeDefinition', 'Type')
+                        .replace('Organizes',      'Org');
+                      return `<span class="${cls}">${label}</span>`;
+                    }
+
+                    function buildUl(nodes) {
+                      const ul = document.createElement('ul');
+                      ul.className = 'tree';
+                      for (const n of nodes) {
+                        const li = document.createElement('li');
+                        li.className = 'node';
+                        const isVar  = n.nodeClass === 'Variable';
+                        const isView = n.nodeClass === 'View';
+                        // NEU: View bekommt 👁-Icon
+                        const icon   = isVar ? '📊' : (isView ? '👁' : '📁');
+                        const toggle = document.createElement('span');
+                        toggle.className = 'toggle';
+                        toggle.textContent = '▶';
+                        toggle.onclick = (e) => { e.stopPropagation(); expand(n.nodeId, li); };
+                        li.appendChild(toggle);
+                        li.insertAdjacentHTML('beforeend',
+                            `<span class="icon">${icon}</span>`
+                          + `<b>${n.displayName || n.browseName}</b>`
+                          + `<span class="nc">${n.nodeClass || ''}</span>`
+                          + refBadge(n.referenceType)
+                          + (isVar && n.value != null ? `<span class="val">${n.value}</span>` : ''));
+                        ul.appendChild(li);
+                      }
+                      return ul;
+                    }
+
+                    async function post(url, body) {
+                      const r = await fetch(url, { method: 'POST',
+                        headers: { 'Content-Type': 'application/json' },
+                        body: JSON.stringify(body) });
+                      const d = await r.json();
+                      if (!d.success) throw new Error(d.error || 'Unknown error');
+                      return d;
+                    }
+
+                    function exportTwin() { window.open('/api/export', '_blank'); }
+
+                    checkStatus();
+                  </script>
+                </body>
+                </html>
+                """;
+        }
+    }
+}
\ No newline at end of file
diff --git a/main/java/de/opcua/app/scripting/GraalScriptEngine.java b/main/java/de/opcua/app/scripting/GraalScriptEngine.java
new file mode 100644
index 0000000..5ee2824
--- /dev/null
+++ b/main/java/de/opcua/app/scripting/GraalScriptEngine.java
@@ -0,0 +1,368 @@
+package de.opcua.app.scripting;
+
+import de.opcua.app.opc.OpcUaService;
+import org.graalvm.polyglot.Context;
+import org.graalvm.polyglot.HostAccess;
+import org.graalvm.polyglot.Value;
+
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * GraalVM-based JavaScript engine.
+ *
+ * Important: GraalVM Context is not thread-safe. Therefore every event/script
+ * execution receives its own isolated Context. This allows parallel execution
+ * where every OPC-UA event/action can run in its own thread without overwriting
+ * global JavaScript variables from another event.
+ */
+public class GraalScriptEngine {
+
+    private final OpcUaService opcService;
+    private final Store store;
+    private final RestClient restClient;
+    private final Map<String, Object> globalBindings;
+    private volatile boolean availabilityChecked = false;
+    private volatile boolean available = false;
+
+    public GraalScriptEngine(OpcUaService opcService, Store store) {
+        this.opcService = opcService;
+        this.store = store;
+        this.restClient = new RestClient();
+        this.globalBindings = new ConcurrentHashMap<>();
+    }
+
+    private Context createContext() {
+        Context context = Context.newBuilder("js")
+                .allowHostAccess(HostAccess.ALL)
+                .allowIO(true)
+                .option("js.ecmascript-version", "2022")
+                .build();
+        initializeContext(context);
+        return context;
+    }
+
+    private void initializeContext(Context context) {
+        var bindings = context.getBindings("js");
+
+        bindings.putMember("opc", new OpcUaFacade(opcService));
+        bindings.putMember("rest", restClient);
+        bindings.putMember("store", store);
+        bindings.putMember("console", new Console());
+        bindings.putMember("sleep", new SleepFunction());
+
+        for (Map.Entry<String, Object> entry : globalBindings.entrySet()) {
+            bindings.putMember(entry.getKey(), entry.getValue());
+        }
+    }
+
+    public boolean isAvailable() {
+        if (availabilityChecked) return available;
+        synchronized (this) {
+            if (availabilityChecked) return available;
+            try (Context ignored = createContext()) {
+                available = true;
+                System.out.println("[GraalVM] JavaScript engine ready");
+            } catch (Exception e) {
+                available = false;
+                System.err.println("[GraalVM] Failed to initialize: " + e.getMessage());
+                System.err.println("[GraalVM] Make sure GraalVM JS dependencies are on the classpath.");
+            } finally {
+                availabilityChecked = true;
+            }
+            return available;
+        }
+    }
+
+    /** Execute JavaScript code without extra per-event bindings. */
+    public Object execute(String script) {
+        return execute(script, Map.of());
+    }
+
+    /** Execute JavaScript code with event-specific bindings. */
+    public Object execute(String script, Map<String, Object> bindings) {
+        if (!isAvailable()) {
+            throw new ScriptExecutionException(
+                    "GraalVM JavaScript engine not available. Make sure graalvm-js dependencies are on classpath.",
+                    null
+            );
+        }
+
+        try (Context context = createContext()) {
+            putBindings(context, bindings);
+            Value result = context.eval("js", script == null ? "" : script);
+            return convertValueToJava(result);
+        } catch (Exception e) {
+            throw new ScriptExecutionException("Script execution failed", e);
+        }
+    }
+
+    /** Evaluate a JavaScript condition and convert the result to boolean semantics. */
+    public boolean executeCondition(String conditionScript, Map<String, Object> bindings) {
+        Object result = execute(conditionScript, bindings);
+        return toBoolean(result);
+    }
+
+    /** Execute script asynchronously. */
+    public CompletableFuture<Object> executeAsync(String script) {
+        return CompletableFuture.supplyAsync(() -> execute(script));
+    }
+
+    public CompletableFuture<Object> executeAsync(String script, Map<String, Object> bindings) {
+        return CompletableFuture.supplyAsync(() -> execute(script, bindings));
+    }
+
+    /** Bind a Java object as a global default for all future event contexts. */
+    public void bind(String name, Object value) {
+        if (name == null || name.isBlank()) return;
+        globalBindings.put(name, value);
+    }
+
+    /** Get a global binding. Event-local bindings are intentionally not retained. */
+    public Object get(String name) {
+        return globalBindings.get(name);
+    }
+
+    private void putBindings(Context context, Map<String, Object> bindings) {
+        if (bindings == null) return;
+        var jsBindings = context.getBindings("js");
+        for (Map.Entry<String, Object> entry : bindings.entrySet()) {
+            String key = entry.getKey();
+            if (key == null || key.isBlank()) continue;
+            jsBindings.putMember(key, entry.getValue());
+        }
+    }
+
+    private Object convertValueToJava(Value value) {
+        if (value == null || value.isNull()) return null;
+        if (value.isBoolean()) return value.asBoolean();
+        if (value.isNumber()) {
+            if (value.fitsInInt()) return value.asInt();
+            if (value.fitsInLong()) return value.asLong();
+            return value.asDouble();
+        }
+        if (value.isString()) return value.asString();
+        if (value.hasArrayElements()) {
+            long size = value.getArraySize();
+            Object[] array = new Object[(int) size];
+            for (int i = 0; i < size; i++) {
+                array[i] = convertValueToJava(value.getArrayElement(i));
+            }
+            return array;
+        }
+        if (value.isHostObject()) return value.asHostObject();
+        return value.toString();
+    }
+
+    private boolean toBoolean(Object result) {
+        if (result == null) return false;
+        if (result instanceof Boolean b) return b;
+        if (result instanceof Number n) return n.doubleValue() != 0.0d;
+        String s = result.toString().trim();
+        if (s.isEmpty()) return false;
+        if ("true".equalsIgnoreCase(s)) return true;
+        if ("false".equalsIgnoreCase(s)) return false;
+        try {
+            return Double.parseDouble(s) != 0.0d;
+        } catch (NumberFormatException ignored) {
+            return true;
+        }
+    }
+
+    public void close() {
+        globalBindings.clear();
+    }
+
+    public static class OpcUaFacade {
+        private final OpcUaService opcService;
+
+        public OpcUaFacade(OpcUaService opcService) {
+            this.opcService = opcService;
+        }
+
+        public String read(String nodeId) {
+            try {
+                return opcService.readValue(nodeId).get();
+            } catch (Exception e) {
+                throw new RuntimeException("Failed to read node: " + nodeId, e);
+            }
+        }
+
+        public boolean write(String nodeId, Object value) {
+            try {
+                return opcService.writeValue(nodeId, value).get();
+            } catch (Exception e) {
+                throw new RuntimeException("Failed to write node: " + nodeId, e);
+            }
+        }
+
+        public Map<String, String> readMultiple(String[] nodeIds) {
+            Map<String, String> results = new HashMap<>();
+            if (nodeIds == null) return results;
+            for (String nodeId : nodeIds) {
+                try {
+                    results.put(nodeId, read(nodeId));
+                } catch (Exception e) {
+                    results.put(nodeId, "<error: " + e.getMessage() + ">");
+                }
+            }
+            return results;
+        }
+
+        public Map<String, String> readMultiple(List<String> nodeIds) {
+            Map<String, String> results = new HashMap<>();
+            if (nodeIds == null) return results;
+            for (String nodeId : nodeIds) {
+                try {
+                    results.put(nodeId, read(nodeId));
+                } catch (Exception e) {
+                    results.put(nodeId, "<error: " + e.getMessage() + ">");
+                }
+            }
+            return results;
+        }
+
+        public boolean writeMultiple(Map<String, Object> valuesByNodeId) {
+            if (valuesByNodeId == null) return true;
+            boolean ok = true;
+            for (Map.Entry<String, Object> entry : valuesByNodeId.entrySet()) {
+                ok &= write(entry.getKey(), entry.getValue());
+            }
+            return ok;
+        }
+
+        public boolean isConnected() {
+            return opcService.isConnected();
+        }
+    }
+
+    public static class RestClient {
+        private final HttpClient httpClient;
+
+        public RestClient() {
+            this.httpClient = HttpClient.newBuilder()
+                    .connectTimeout(Duration.ofSeconds(10))
+                    .build();
+        }
+
+        public RestResponse get(String url) { return get(url, null); }
+
+        public RestResponse get(String url, Map<String, String> headers) {
+            try {
+                HttpRequest.Builder builder = HttpRequest.newBuilder().uri(URI.create(url)).GET();
+                if (headers != null) headers.forEach(builder::header);
+                HttpResponse<String> response = httpClient.send(builder.build(), HttpResponse.BodyHandlers.ofString());
+                return new RestResponse(response.statusCode(), response.body(), response.headers().map());
+            } catch (Exception e) {
+                throw new RuntimeException("GET request failed: " + url, e);
+            }
+        }
+
+        public RestResponse post(String url, String body) { return post(url, body, null); }
+
+        public RestResponse post(String url, String body, Map<String, String> headers) {
+            try {
+                HttpRequest.Builder builder = HttpRequest.newBuilder()
+                        .uri(URI.create(url))
+                        .POST(HttpRequest.BodyPublishers.ofString(body == null ? "" : body))
+                        .header("Content-Type", "application/json");
+                if (headers != null) headers.forEach(builder::header);
+                HttpResponse<String> response = httpClient.send(builder.build(), HttpResponse.BodyHandlers.ofString());
+                return new RestResponse(response.statusCode(), response.body(), response.headers().map());
+            } catch (Exception e) {
+                throw new RuntimeException("POST request failed: " + url, e);
+            }
+        }
+
+        public RestResponse put(String url, String body) { return put(url, body, null); }
+
+        public RestResponse put(String url, String body, Map<String, String> headers) {
+            try {
+                HttpRequest.Builder builder = HttpRequest.newBuilder()
+                        .uri(URI.create(url))
+                        .PUT(HttpRequest.BodyPublishers.ofString(body == null ? "" : body))
+                        .header("Content-Type", "application/json");
+                if (headers != null) headers.forEach(builder::header);
+                HttpResponse<String> response = httpClient.send(builder.build(), HttpResponse.BodyHandlers.ofString());
+                return new RestResponse(response.statusCode(), response.body(), response.headers().map());
+            } catch (Exception e) {
+                throw new RuntimeException("PUT request failed: " + url, e);
+            }
+        }
+
+        public RestResponse delete(String url) { return delete(url, null); }
+
+        public RestResponse delete(String url, Map<String, String> headers) {
+            try {
+                HttpRequest.Builder builder = HttpRequest.newBuilder().uri(URI.create(url)).DELETE();
+                if (headers != null) headers.forEach(builder::header);
+                HttpResponse<String> response = httpClient.send(builder.build(), HttpResponse.BodyHandlers.ofString());
+                return new RestResponse(response.statusCode(), response.body(), response.headers().map());
+            } catch (Exception e) {
+                throw new RuntimeException("DELETE request failed: " + url, e);
+            }
+        }
+    }
+
+    public static class RestResponse {
+        private final int status;
+        private final String body;
+        private final Map<String, java.util.List<String>> headers;
+
+        public RestResponse(int status, String body, Map<String, java.util.List<String>> headers) {
+            this.status = status;
+            this.body = body;
+            this.headers = headers;
+        }
+
+        public int getStatus() { return status; }
+        public String getBody() { return body; }
+        public Map<String, java.util.List<String>> getHeaders() { return headers; }
+        public String json() { return body; }
+        public boolean isOk() { return status >= 200 && status < 300; }
+    }
+
+    public static class Console {
+        public void log(Object... messages) {
+            StringBuilder sb = new StringBuilder("[JS] ");
+            for (Object msg : messages) sb.append(msg).append(" ");
+            System.out.println(sb.toString().trim());
+        }
+
+        public void error(Object... messages) {
+            StringBuilder sb = new StringBuilder("[JS ERROR] ");
+            for (Object msg : messages) sb.append(msg).append(" ");
+            System.err.println(sb.toString().trim());
+        }
+
+        public void warn(Object... messages) {
+            StringBuilder sb = new StringBuilder("[JS WARN] ");
+            for (Object msg : messages) sb.append(msg).append(" ");
+            System.out.println(sb.toString().trim());
+        }
+    }
+
+    public static class SleepFunction {
+        public void sleep(long milliseconds) {
+            try {
+                Thread.sleep(milliseconds);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        }
+    }
+
+    public static class ScriptExecutionException extends RuntimeException {
+        public ScriptExecutionException(String message, Throwable cause) {
+            super(message, cause);
+        }
+    }
+}
diff --git a/main/java/de/opcua/app/scripting/ScriptService.java b/main/java/de/opcua/app/scripting/ScriptService.java
new file mode 100644
index 0000000..095d3b9
--- /dev/null
+++ b/main/java/de/opcua/app/scripting/ScriptService.java
@@ -0,0 +1,29 @@
+package de.opcua.app.scripting;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ScriptService {
+
+    private final Map<String, Object> bindings = new HashMap<>();
+
+    public ScriptService() {
+        // aktuell kein JS-Engine vorhanden
+    }
+
+    /** Gibt an, ob Scripting verfügbar ist */
+    public boolean isAvailable() {
+        return false; // bewusst deaktiviert
+    }
+
+    /** Platzhalter für spätere Engine */
+    public Object eval(String code) {
+        throw new UnsupportedOperationException(
+                "Scripting ist deaktiviert (keine JS-Engine vorhanden)");
+    }
+
+    /** Bindings registrieren (werden aktuell ignoriert) */
+    public void put(String name, Object value) {
+        bindings.put(name, value);
+    }
+}
diff --git a/main/java/de/opcua/app/scripting/Store.java b/main/java/de/opcua/app/scripting/Store.java
new file mode 100644
index 0000000..49a07d7
--- /dev/null
+++ b/main/java/de/opcua/app/scripting/Store.java
@@ -0,0 +1,13 @@
+package de.opcua.app.scripting;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public final class Store {
+  private final Map<String, Object> data = new ConcurrentHashMap<>();
+
+  public Object get(String key) { return data.get(key); }
+  public void set(String key, Object value) { data.put(key, value); }
+  public void clear() { data.clear(); }
+  public Map<String, Object> snapshot() { return Map.copyOf(data); }
+}
diff --git a/main/java/de/opcua/app/service/ActionPersistenceService.java b/main/java/de/opcua/app/service/ActionPersistenceService.java
new file mode 100644
index 0000000..6f3a0ae
--- /dev/null
+++ b/main/java/de/opcua/app/service/ActionPersistenceService.java
@@ -0,0 +1,157 @@
+package de.opcua.app.service;
+
+import de.opcua.app.model.NodeAction;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Timer;
+import java.util.TimerTask;
+
+/**
+ * Persists Actions to JSON file.
+ */
+public class ActionPersistenceService {
+
+    private static final String CONFIG_DIR = System.getProperty("user.home") + "/.opcua-gui";
+    private static final String ACTIONS_FILE = CONFIG_DIR + "/actions.json";
+
+    private final ObjectMapper mapper;
+
+    public ActionPersistenceService() {
+        this.mapper = new ObjectMapper();
+        this.mapper.enable(SerializationFeature.INDENT_OUTPUT);
+        ensureConfigDir();
+    }
+
+    private void ensureConfigDir() {
+        try {
+            Path dir = Paths.get(CONFIG_DIR);
+            if (!Files.exists(dir)) {
+                Files.createDirectories(dir);
+                System.out.println("[Persistence] Created config directory: " + CONFIG_DIR);
+            }
+        } catch (IOException e) {
+            System.err.println("[Persistence] Failed to create config directory: " + e.getMessage());
+        }
+    }
+
+    public void saveActions(Map<String, List<NodeAction>> actions) {
+        try {
+            List<ActionData> dataList = new ArrayList<>();
+
+            for (Map.Entry<String, List<NodeAction>> entry : actions.entrySet()) {
+                String nodeId = entry.getKey();
+                for (NodeAction action : entry.getValue()) {
+                    ActionData data = new ActionData(
+                            nodeId,
+                            action.getActionName(),
+                            action.getTriggerType().name(),
+                            action.getScript(),
+                            action.getTriggerValue(),
+                            action.getIntervalMs(),
+                            action.isEnabled()
+                    );
+                    data.conditionEnabled = action.isConditionEnabled();
+                    data.conditionScript = action.getConditionScript();
+                    data.conditionNodeIds = new ArrayList<>(action.getConditionNodeIds());
+                    data.nodeAliases = new LinkedHashMap<>(action.getNodeAliases());
+                    dataList.add(data);
+                }
+            }
+
+            mapper.writeValue(new File(ACTIONS_FILE), dataList);
+            System.out.println("[Persistence] Saved " + dataList.size() + " actions to " + ACTIONS_FILE);
+
+        } catch (IOException e) {
+            System.err.println("[Persistence] Failed to save actions: " + e.getMessage());
+        }
+    }
+
+    public Map<String, List<NodeAction>> loadActions() {
+        Map<String, List<NodeAction>> result = new HashMap<>();
+
+        File file = new File(ACTIONS_FILE);
+        if (!file.exists()) {
+            System.out.println("[Persistence] No saved actions found");
+            return result;
+        }
+
+        try {
+            ActionData[] dataArray = mapper.readValue(file, ActionData[].class);
+
+            for (ActionData data : dataArray) {
+                NodeAction action = new NodeAction();
+                action.setNodeId(data.nodeId);
+                action.setActionName(data.actionName);
+                action.setTriggerType(NodeAction.TriggerType.valueOf(data.triggerType));
+                action.setScript(data.script);
+                action.setTriggerValue(data.triggerValue);
+                action.setIntervalMs(data.intervalMs);
+                action.setEnabled(data.enabled);
+                action.setConditionEnabled(data.conditionEnabled);
+                action.setConditionScript(data.conditionScript);
+                action.setConditionNodeIds(data.conditionNodeIds);
+                action.setNodeAliases(data.nodeAliases);
+
+                result.computeIfAbsent(data.nodeId, k -> new ArrayList<>()).add(action);
+            }
+
+            System.out.println("[Persistence] Loaded " + dataArray.length + " actions from " + ACTIONS_FILE);
+
+        } catch (IOException e) {
+            System.err.println("[Persistence] Failed to load actions: " + e.getMessage());
+        }
+
+        return result;
+    }
+
+    public void startAutoSave(ActionService actionService, int intervalSeconds) {
+        Timer timer = new Timer("ActionAutoSave", true);
+        timer.scheduleAtFixedRate(new TimerTask() {
+            @Override
+            public void run() {
+                saveActions(actionService.getAllActions());
+            }
+        }, intervalSeconds * 1000L, intervalSeconds * 1000L);
+
+        System.out.println("[Persistence] Auto-save enabled (every " + intervalSeconds + "s)");
+    }
+
+    public static class ActionData {
+        public String nodeId;
+        public String actionName;
+        public String triggerType;
+        public String script;
+        public String triggerValue;
+        public int intervalMs;
+        public boolean enabled;
+
+        public boolean conditionEnabled;
+        public String conditionScript;
+        public List<String> conditionNodeIds = new ArrayList<>();
+        public Map<String, String> nodeAliases = new LinkedHashMap<>();
+
+        public ActionData() {}
+
+        public ActionData(String nodeId, String actionName, String triggerType,
+                          String script, String triggerValue, int intervalMs, boolean enabled) {
+            this.nodeId = nodeId;
+            this.actionName = actionName;
+            this.triggerType = triggerType;
+            this.script = script;
+            this.triggerValue = triggerValue;
+            this.intervalMs = intervalMs;
+            this.enabled = enabled;
+        }
+    }
+}
diff --git a/main/java/de/opcua/app/service/ActionService.java b/main/java/de/opcua/app/service/ActionService.java
new file mode 100644
index 0000000..b2badc9
--- /dev/null
+++ b/main/java/de/opcua/app/service/ActionService.java
@@ -0,0 +1,360 @@
+package de.opcua.app.service;
+
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.scripting.GraalScriptEngine;
+import de.opcua.app.scripting.Store;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.stream.Collectors;
+
+/**
+ * Manages and executes actions associated with OPC UA nodes.
+ * Each triggered event is executed on its own worker thread. The JavaScript
+ * context is created per event in GraalScriptEngine, so variables from parallel
+ * events cannot overwrite each other.
+ */
+public class ActionService {
+
+    private final OpcUaService opcService;
+    private final GraalScriptEngine scriptEngine;
+    private final Map<String, List<NodeAction>> nodeActions;  // nodeId -> actions
+    private final ScheduledExecutorService scheduler;
+    private final ExecutorService eventExecutor;
+    private final Map<String, ScheduledFuture<?>> intervalTasks;
+    private final AtomicLong eventSequence = new AtomicLong();
+
+    public ActionService(OpcUaService opcService, Store store) {
+        this.opcService = opcService;
+        this.scriptEngine = new GraalScriptEngine(opcService, store);
+        this.nodeActions = new ConcurrentHashMap<>();
+        this.scheduler = Executors.newScheduledThreadPool(4, r -> {
+            Thread t = new Thread(r, "opcua-action-scheduler");
+            t.setDaemon(true);
+            return t;
+        });
+        this.eventExecutor = Executors.newCachedThreadPool(r -> {
+            long id = eventSequence.incrementAndGet();
+            Thread t = new Thread(r, "opcua-event-script-" + id);
+            t.setDaemon(true);
+            return t;
+        });
+        this.intervalTasks = new ConcurrentHashMap<>();
+    }
+
+    public void addAction(NodeAction action) {
+        if (action == null || action.getNodeId() == null || action.getNodeId().isBlank()) return;
+        String nodeId = action.getNodeId();
+        removeAction(nodeId, action.getActionName());
+        nodeActions.computeIfAbsent(nodeId, k -> new CopyOnWriteArrayList<>()).add(action);
+
+        if (action.getTriggerType() == NodeAction.TriggerType.ON_INTERVAL) {
+            scheduleIntervalAction(action);
+        }
+
+        System.out.println("Added action: " + action.getActionName() + " for node " + nodeId);
+    }
+
+    public void removeAction(String nodeId, String actionName) {
+        if (nodeId == null || actionName == null) return;
+        List<NodeAction> actions = nodeActions.get(nodeId);
+        if (actions != null) {
+            actions.removeIf(a -> actionName.equals(a.getActionName()));
+            if (actions.isEmpty()) nodeActions.remove(nodeId);
+
+            String taskKey = nodeId + ":" + actionName;
+            ScheduledFuture<?> task = intervalTasks.remove(taskKey);
+            if (task != null) task.cancel(false);
+        }
+    }
+
+    public List<NodeAction> getActions(String nodeId) {
+        return nodeActions.getOrDefault(nodeId, Collections.emptyList());
+    }
+
+    public Map<String, List<NodeAction>> getAllActions() {
+        return new HashMap<>(nodeActions);
+    }
+
+    public List<NodeAction> getAllActionsFlat() {
+        return nodeActions.values().stream()
+                .flatMap(List::stream)
+                .collect(Collectors.toList());
+    }
+
+    public void processValueChange(String nodeId, String newValue) {
+        List<NodeAction> actions = nodeActions.get(nodeId);
+        if (actions == null || actions.isEmpty()) return;
+
+        for (NodeAction action : actions) {
+            if (action.shouldTrigger(newValue)) {
+                executeAction(action, newValue);
+            }
+        }
+    }
+
+    private void executeAction(NodeAction action, String currentValue) {
+        eventExecutor.submit(() -> {
+            long eventId = eventSequence.incrementAndGet();
+            try {
+                System.out.println("Executing action: " + action.getActionName() +
+                        " for node " + action.getNodeId() +
+                        " with value: " + currentValue +
+                        " on " + Thread.currentThread().getName());
+
+                Map<String, Object> bindings = buildBindings(action, currentValue, eventId);
+
+                if (action.isConditionEnabled() && action.getConditionScript() != null && !action.getConditionScript().isBlank()) {
+                    boolean conditionOk = scriptEngine.executeCondition(action.getConditionScript(), bindings);
+                    if (!conditionOk) {
+                        System.out.println("Action skipped by condition: " + action.getActionName());
+                        return;
+                    }
+                }
+
+                Object result = scriptEngine.execute(action.getScript(), bindings);
+                System.out.println("Action completed: " + action.getActionName() + " Result: " + result);
+
+            } catch (Exception e) {
+                System.err.println("Error executing action " + action.getActionName() + ": " + e.getMessage());
+                e.printStackTrace();
+            }
+        });
+    }
+
+    private Map<String, Object> buildBindings(NodeAction action, String currentValue, long eventId) {
+        Map<String, Object> bindings = new LinkedHashMap<>();
+        Map<String, String> selectedNodes = new LinkedHashMap<>();      // alias -> nodeId
+        Map<String, String> selectedValues = new LinkedHashMap<>();     // alias -> current value
+        List<String> selectedNodeIds = action.getConditionNodeIds() != null
+                ? new ArrayList<>(action.getConditionNodeIds())
+                : new ArrayList<>();
+
+        if (!selectedNodeIds.contains(action.getNodeId())) {
+            selectedNodeIds.add(0, action.getNodeId());
+        }
+
+        Map<String, String> aliasesByNodeId = action.getNodeAliases() != null
+                ? action.getNodeAliases()
+                : Map.of();
+
+        for (String nodeId : selectedNodeIds) {
+            String alias = aliasesByNodeId.getOrDefault(nodeId, createAlias(nodeId));
+            alias = createSafeAlias(alias);
+            selectedNodes.put(alias, nodeId);
+
+            String value;
+            if (nodeId.equals(action.getNodeId())) {
+                value = currentValue;
+            } else {
+                try {
+                    value = opcService.readValueSync(nodeId);
+                } catch (Exception e) {
+                    value = "<error: " + e.getMessage() + ">";
+                }
+            }
+            selectedValues.put(alias, value);
+
+            // Direct variables from checkbox selection, e.g. Temperature = "72.0"
+            bindings.put(alias, value);
+        }
+
+        Map<String, Object> event = new LinkedHashMap<>();
+        event.put("id", eventId);
+        event.put("thread", Thread.currentThread().getName());
+        event.put("nodeId", action.getNodeId());
+        event.put("actionName", action.getActionName());
+        event.put("currentValue", currentValue);
+        event.put("selectedNodeIds", selectedNodeIds);
+        event.put("nodes", selectedNodes);
+        event.put("values", selectedValues);
+
+        bindings.put("event", event);
+        bindings.put("currentValue", currentValue);
+        bindings.put("nodeId", action.getNodeId());
+        bindings.put("actionName", action.getActionName());
+        bindings.put("selectedNodeIds", selectedNodeIds);
+        bindings.put("nodes", selectedNodes);
+        bindings.put("selectedNodes", selectedNodes);
+        bindings.put("values", selectedValues);
+        bindings.put("selectedValues", selectedValues);
+
+        return bindings;
+    }
+
+    private String createAlias(String nodeId) {
+        if (nodeId == null) return "node";
+        int idx = Math.max(nodeId.lastIndexOf('.'), nodeId.lastIndexOf('='));
+        String raw = idx >= 0 && idx < nodeId.length() - 1 ? nodeId.substring(idx + 1) : nodeId;
+        return createSafeAlias(raw);
+    }
+
+    private String createSafeAlias(String text) {
+        if (text == null || text.isBlank()) return "node";
+        String alias = text.replaceAll("[^A-Za-z0-9_$]", "_");
+        if (!alias.matches("[A-Za-z_$].*")) alias = "n_" + alias;
+        return alias;
+    }
+
+    private void scheduleIntervalAction(NodeAction action) {
+        String taskKey = action.getNodeId() + ":" + action.getActionName();
+
+        ScheduledFuture<?> existingTask = intervalTasks.get(taskKey);
+        if (existingTask != null) existingTask.cancel(false);
+
+        int interval = Math.max(100, action.getIntervalMs());
+        ScheduledFuture<?> task = scheduler.scheduleAtFixedRate(() -> {
+            if (action.isEnabled()) {
+                try {
+                    String currentValue = opcService.readValue(action.getNodeId()).get(5, TimeUnit.SECONDS);
+                    executeAction(action, currentValue);
+                } catch (Exception e) {
+                    System.err.println("Error in interval action " + action.getActionName() + ": " + e.getMessage());
+                }
+            }
+        }, interval, interval, TimeUnit.MILLISECONDS);
+
+        intervalTasks.put(taskKey, task);
+    }
+
+    public void setActionEnabled(String nodeId, String actionName, boolean enabled) {
+        List<NodeAction> actions = nodeActions.get(nodeId);
+        if (actions != null) {
+            actions.stream()
+                    .filter(a -> a.getActionName().equals(actionName))
+                    .forEach(a -> a.setEnabled(enabled));
+        }
+    }
+
+    public void testAction(String nodeId, String actionName, String testValue) {
+        List<NodeAction> actions = nodeActions.get(nodeId);
+        if (actions != null) {
+            actions.stream()
+                    .filter(a -> a.getActionName().equals(actionName))
+                    .forEach(a -> executeAction(a, testValue));
+        }
+    }
+
+    public GraalScriptEngine getScriptEngine() {
+        return scriptEngine;
+    }
+
+    public void shutdown() {
+        intervalTasks.values().forEach(task -> task.cancel(false));
+        intervalTasks.clear();
+
+        scheduler.shutdown();
+        eventExecutor.shutdown();
+        try {
+            if (!scheduler.awaitTermination(5, TimeUnit.SECONDS)) scheduler.shutdownNow();
+            if (!eventExecutor.awaitTermination(10, TimeUnit.SECONDS)) eventExecutor.shutdownNow();
+        } catch (InterruptedException e) {
+            scheduler.shutdownNow();
+            eventExecutor.shutdownNow();
+            Thread.currentThread().interrupt();
+        }
+
+        scriptEngine.close();
+    }
+
+    public Map<String, Object> exportActions() {
+        Map<String, Object> export = new HashMap<>();
+
+        for (Map.Entry<String, List<NodeAction>> entry : nodeActions.entrySet()) {
+            List<Map<String, Object>> actionsList = entry.getValue().stream()
+                    .map(this::actionToMap)
+                    .collect(Collectors.toList());
+            export.put(entry.getKey(), actionsList);
+        }
+
+        return export;
+    }
+
+    private Map<String, Object> actionToMap(NodeAction action) {
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("actionName", action.getActionName());
+        map.put("triggerType", action.getTriggerType().name());
+        map.put("script", action.getScript());
+        map.put("triggerValue", action.getTriggerValue());
+        map.put("intervalMs", action.getIntervalMs());
+        map.put("enabled", action.isEnabled());
+        map.put("conditionEnabled", action.isConditionEnabled());
+        map.put("conditionScript", action.getConditionScript());
+        map.put("conditionNodeIds", action.getConditionNodeIds());
+        map.put("nodeAliases", action.getNodeAliases());
+        return map;
+    }
+
+    public void importActions(Map<String, Object> data) {
+        nodeActions.clear();
+
+        for (Map.Entry<String, Object> entry : data.entrySet()) {
+            String nodeId = entry.getKey();
+            @SuppressWarnings("unchecked")
+            List<Map<String, Object>> actionsList = (List<Map<String, Object>>) entry.getValue();
+
+            for (Map<String, Object> actionMap : actionsList) {
+                NodeAction action = mapToAction(nodeId, actionMap);
+                addAction(action);
+            }
+        }
+    }
+
+    public void importActionsFromList(Map<String, List<NodeAction>> data) {
+        nodeActions.clear();
+
+        for (Map.Entry<String, List<NodeAction>> entry : data.entrySet()) {
+            for (NodeAction action : entry.getValue()) {
+                addAction(action);
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private NodeAction mapToAction(String nodeId, Map<String, Object> map) {
+        NodeAction action = new NodeAction();
+        action.setNodeId(nodeId);
+        action.setActionName((String) map.get("actionName"));
+        action.setTriggerType(NodeAction.TriggerType.valueOf((String) map.get("triggerType")));
+        action.setScript((String) map.get("script"));
+        action.setTriggerValue((String) map.get("triggerValue"));
+
+        Object intervalMs = map.get("intervalMs");
+        if (intervalMs instanceof Number) action.setIntervalMs(((Number) intervalMs).intValue());
+
+        Object enabled = map.get("enabled");
+        if (enabled instanceof Boolean) action.setEnabled((Boolean) enabled);
+
+        Object conditionEnabled = map.get("conditionEnabled");
+        if (conditionEnabled instanceof Boolean) action.setConditionEnabled((Boolean) conditionEnabled);
+
+        action.setConditionScript((String) map.getOrDefault("conditionScript", ""));
+
+        Object conditionNodeIds = map.get("conditionNodeIds");
+        if (conditionNodeIds instanceof List<?>) {
+            action.setConditionNodeIds(((List<?>) conditionNodeIds).stream().map(String::valueOf).collect(Collectors.toList()));
+        }
+
+        Object nodeAliases = map.get("nodeAliases");
+        if (nodeAliases instanceof Map<?, ?> aliases) {
+            Map<String, String> converted = new LinkedHashMap<>();
+            aliases.forEach((k, v) -> converted.put(String.valueOf(k), String.valueOf(v)));
+            action.setNodeAliases(converted);
+        }
+
+        return action;
+    }
+}
diff --git a/main/java/de/opcua/app/service/AppMode.java b/main/java/de/opcua/app/service/AppMode.java
new file mode 100644
index 0000000..328a9f9
--- /dev/null
+++ b/main/java/de/opcua/app/service/AppMode.java
@@ -0,0 +1,15 @@
+package de.opcua.app.service;
+
+public enum AppMode {
+  UI,
+  SERVICE;
+
+  public static AppMode fromArgs(String[] args) {
+    if (args == null) return UI;
+    for (String a : args) {
+      if (a == null) continue;
+      if (a.equalsIgnoreCase("--service") || a.equalsIgnoreCase("service")) return SERVICE;
+    }
+    return UI;
+  }
+}
diff --git a/main/java/de/opcua/app/test/MinimalRestTest.java b/main/java/de/opcua/app/test/MinimalRestTest.java
new file mode 100644
index 0000000..caac88d
--- /dev/null
+++ b/main/java/de/opcua/app/test/MinimalRestTest.java
@@ -0,0 +1,66 @@
+package de.opcua.app.test;
+
+import com.sun.net.httpserver.*;
+import java.io.*;
+import java.net.InetSocketAddress;
+
+/**
+ * Minimal test to verify HttpServer works
+ * Run with: mvn exec:java -Dexec.mainClass="de.opcua.app.test.MinimalRestTest"
+ */
+public class MinimalRestTest {
+    
+    public static void main(String[] args) {
+        try {
+            System.out.println("Creating HTTP Server on port 8081...");
+            
+            HttpServer server = HttpServer.create(new InetSocketAddress(8081), 0);
+            
+            server.createContext("/", exchange -> {
+                String html = "<html><body><h1>It Works!</h1><p>REST API is running on port 8081</p></body></html>";
+                byte[] bytes = html.getBytes("UTF-8");
+                
+                exchange.getResponseHeaders().set("Content-Type", "text/html; charset=UTF-8");
+                exchange.sendResponseHeaders(200, bytes.length);
+                exchange.getResponseBody().write(bytes);
+                exchange.getResponseBody().close();
+            });
+            
+            server.createContext("/test", exchange -> {
+                String json = "{\"status\":\"ok\",\"message\":\"Test endpoint works!\"}";
+                byte[] bytes = json.getBytes("UTF-8");
+                
+                exchange.getResponseHeaders().set("Content-Type", "application/json");
+                exchange.sendResponseHeaders(200, bytes.length);
+                exchange.getResponseBody().write(bytes);
+                exchange.getResponseBody().close();
+            });
+            
+            server.start();
+            
+            System.out.println("✅ HTTP Server started successfully!");
+            System.out.println("✅ Open in browser: http://localhost:8081/");
+            System.out.println("✅ Test endpoint: http://localhost:8081/test");
+            System.out.println("");
+            System.out.println("Test with curl:");
+            System.out.println("  curl http://localhost:8081/");
+            System.out.println("  curl http://localhost:8081/test");
+            System.out.println("");
+            System.out.println("Press Ctrl+C to stop...");
+            
+            Thread.sleep(Long.MAX_VALUE);
+            
+        } catch (Exception e) {
+            System.err.println("❌ Failed to start server!");
+            System.err.println("Error: " + e.getMessage());
+            e.printStackTrace();
+            
+            System.err.println("");
+            System.err.println("Possible causes:");
+            System.err.println("1. Port 8081 is already in use");
+            System.err.println("   Check with: lsof -i :8081");
+            System.err.println("2. Firewall is blocking the port");
+            System.err.println("3. Insufficient permissions");
+        }
+    }
+}
diff --git a/main/java/de/opcua/app/ui/ActionButtonHelper.java b/main/java/de/opcua/app/ui/ActionButtonHelper.java
new file mode 100644
index 0000000..b7977a5
--- /dev/null
+++ b/main/java/de/opcua/app/ui/ActionButtonHelper.java
@@ -0,0 +1,418 @@
+package de.opcua.app.controller;
+
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.model.NodeRow;
+import de.opcua.app.service.ActionService;
+import javafx.geometry.Insets;
+import javafx.geometry.Pos;
+import javafx.scene.control.*;
+import javafx.scene.layout.GridPane;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.Priority;
+import javafx.scene.layout.VBox;
+
+/**
+ * COMPLETELY FIXED: All fields are now fully editable and functional
+ */
+public class ActionButtonHelper {
+    
+    private final ActionService actionService;
+    
+    public ActionButtonHelper(ActionService actionService) {
+        this.actionService = actionService;
+    }
+    
+    public TableColumn<NodeRow, Void> createActionColumn() {
+        TableColumn<NodeRow, Void> actionCol = new TableColumn<>("Actions");
+        actionCol.setPrefWidth(120);
+        
+        actionCol.setCellFactory(param -> new TableCell<>() {
+            private final Button btnActions = new Button("Actions");
+            private final HBox container = new HBox(5);
+            
+            {
+                btnActions.setMaxWidth(Double.MAX_VALUE);
+                container.getChildren().add(btnActions);
+                container.setAlignment(Pos.CENTER);
+                
+                btnActions.setOnAction(event -> {
+                    NodeRow row = getTableView().getItems().get(getIndex());
+                    if (row != null && row.isSelected()) {
+                        showActionDialog(row);
+                    }
+                });
+            }
+            
+            @Override
+            protected void updateItem(Void item, boolean empty) {
+                super.updateItem(item, empty);
+                
+                if (empty || getIndex() >= getTableView().getItems().size()) {
+                    setGraphic(null);
+                } else {
+                    NodeRow row = getTableView().getItems().get(getIndex());
+                    if (row != null && row.isSelected() && row.isReadable()) {
+                        setGraphic(container);
+                    } else {
+                        setGraphic(null);
+                    }
+                }
+            }
+        });
+        
+        return actionCol;
+    }
+    
+    private void showActionDialog(NodeRow nodeRow) {
+        Dialog<ButtonType> dialog = new Dialog<>();
+        dialog.setTitle("Manage Actions");
+        dialog.setHeaderText("Actions for: " + nodeRow.getDisplayName() + "\nNode: " + nodeRow.getNodeId());
+        
+        VBox mainBox = new VBox(10);
+        mainBox.setPadding(new Insets(10));
+        mainBox.setPrefWidth(700);
+        mainBox.setPrefHeight(400);
+        
+        ListView<NodeAction> actionList = new ListView<>();
+        actionList.setPrefHeight(300);
+        actionList.getItems().addAll(actionService.getActions(nodeRow.getNodeId()));
+        VBox.setVgrow(actionList, Priority.ALWAYS);
+        
+        actionList.setCellFactory(param -> new ListCell<>() {
+            @Override
+            protected void updateItem(NodeAction action, boolean empty) {
+                super.updateItem(action, empty);
+                if (empty || action == null) {
+                    setGraphic(null);
+                } else {
+                    HBox cell = new HBox(10);
+                    cell.setAlignment(Pos.CENTER_LEFT);
+                    cell.setPadding(new Insets(5));
+                    
+                    CheckBox enabled = new CheckBox();
+                    enabled.setSelected(action.isEnabled());
+                    enabled.setOnAction(e -> actionService.setActionEnabled(
+                        action.getNodeId(), 
+                        action.getActionName(), 
+                        enabled.isSelected()
+                    ));
+                    
+                    Label label = new Label(action.getActionName() + " (" + action.getTriggerType() + ")");
+                    label.setMinWidth(250);
+                    HBox.setHgrow(label, Priority.ALWAYS);
+                    
+                    Button btnEdit = new Button("Edit");
+                    btnEdit.setOnAction(e -> {
+                        editAction(action);
+                        actionList.refresh();
+                    });
+                    
+                    Button btnTest = new Button("Test");
+                    btnTest.setOnAction(e -> testAction(action, nodeRow));
+                    
+                    Button btnDelete = new Button("Delete");
+                    btnDelete.setOnAction(e -> {
+                        actionService.removeAction(action.getNodeId(), action.getActionName());
+                        actionList.getItems().remove(action);
+                    });
+                    
+                    cell.getChildren().addAll(enabled, label, btnEdit, btnTest, btnDelete);
+                    setGraphic(cell);
+                }
+            }
+        });
+        
+        HBox buttonBox = new HBox(10);
+        buttonBox.setAlignment(Pos.CENTER_LEFT);
+        
+        Button addButton = new Button("Add New Action");
+        addButton.setOnAction(e -> {
+            NodeAction newAction = createNewAction(nodeRow);
+            if (newAction != null) {
+                actionService.addAction(newAction);
+                actionList.getItems().add(newAction);
+            }
+        });
+        
+        buttonBox.getChildren().add(addButton);
+        
+        mainBox.getChildren().addAll(actionList, buttonBox);
+        
+        dialog.getDialogPane().setContent(mainBox);
+        dialog.getDialogPane().getButtonTypes().addAll(ButtonType.CLOSE);
+        dialog.setResizable(true);
+        dialog.showAndWait();
+    }
+    
+    private NodeAction createNewAction(NodeRow nodeRow) {
+        Dialog<NodeAction> dialog = new Dialog<>();
+        dialog.setTitle("Create New Action");
+        dialog.setHeaderText("Add action for: " + nodeRow.getDisplayName());
+        dialog.setResizable(true);
+        
+        // Main container
+        VBox mainContainer = new VBox(15);
+        mainContainer.setPadding(new Insets(20));
+        mainContainer.setPrefWidth(600);
+        
+        // Name field
+        Label nameLabel = new Label("Action Name:");
+        nameLabel.setStyle("-fx-font-weight: bold;");
+        TextField nameField = new TextField();
+        nameField.setPromptText("e.g., Temperature Alarm");
+        nameField.setEditable(true);  // ✅ EXPLICITLY EDITABLE
+        nameField.setDisable(false);  // ✅ NOT DISABLED
+        
+        // Trigger type
+        Label triggerLabel = new Label("Trigger Type:");
+        triggerLabel.setStyle("-fx-font-weight: bold;");
+        ComboBox<NodeAction.TriggerType> triggerCombo = new ComboBox<>();
+        triggerCombo.getItems().addAll(NodeAction.TriggerType.values());
+        triggerCombo.setValue(NodeAction.TriggerType.ON_CHANGE);
+        triggerCombo.setMaxWidth(Double.MAX_VALUE);
+        triggerCombo.setEditable(false);  // ✅ ComboBox should not be text-editable
+        triggerCombo.setDisable(false);   // ✅ But should be selectable
+        
+        // Trigger value
+        Label valueLabel = new Label("Trigger Value (for ON_VALUE, ON_GREATER_THAN, ON_LESS_THAN):");
+        TextField triggerValueField = new TextField();
+        triggerValueField.setPromptText("e.g., 100");
+        triggerValueField.setEditable(true);
+        triggerValueField.setDisable(true);  // Initially disabled
+        
+        // Interval
+        Label intervalLabel = new Label("Interval in milliseconds (for ON_INTERVAL):");
+        TextField intervalField = new TextField("1000");
+        intervalField.setPromptText("e.g., 5000");
+        intervalField.setEditable(true);
+        intervalField.setDisable(true);  // Initially disabled
+        
+        // Script area
+        Label scriptLabel = new Label("JavaScript Code:");
+        scriptLabel.setStyle("-fx-font-weight: bold;");
+        TextArea scriptArea = new TextArea();
+        scriptArea.setPromptText(
+            "Example JavaScript:\n\n" +
+            "console.log('Value changed:', currentValue);\n" +
+            "console.log('Node:', nodeId);\n\n" +
+            "// Read from OPC UA\n" +
+            "var temp = opc.read('ns=2;s=Temperature');\n\n" +
+            "// Write to OPC UA\n" +
+            "opc.write('ns=2;s=Output', '123');\n\n" +
+            "// REST API call\n" +
+            "var response = rest.post(\n" +
+            "  'https://api.example.com/alert',\n" +
+            "  JSON.stringify({value: currentValue})\n" +
+            ");\n\n" +
+            "// Store data\n" +
+            "store.set('lastValue', currentValue);"
+        );
+        scriptArea.setPrefRowCount(12);
+        scriptArea.setWrapText(true);
+        scriptArea.setEditable(true);  // ✅ EXPLICITLY EDITABLE
+        scriptArea.setDisable(false);  // ✅ NOT DISABLED
+        VBox.setVgrow(scriptArea, Priority.ALWAYS);
+        
+        // Dynamic field enabling
+        triggerCombo.valueProperty().addListener((obs, oldVal, newVal) -> {
+            if (newVal == null) return;
+            
+            boolean needsValue = newVal == NodeAction.TriggerType.ON_VALUE ||
+                                newVal == NodeAction.TriggerType.ON_GREATER_THAN ||
+                                newVal == NodeAction.TriggerType.ON_LESS_THAN;
+            triggerValueField.setDisable(!needsValue);
+            
+            boolean needsInterval = newVal == NodeAction.TriggerType.ON_INTERVAL;
+            intervalField.setDisable(!needsInterval);
+            
+            // Update script prompt based on trigger
+            updateScriptPrompt(scriptArea, newVal);
+        });
+        
+        // Add all to container
+        mainContainer.getChildren().addAll(
+            nameLabel, nameField,
+            triggerLabel, triggerCombo,
+            valueLabel, triggerValueField,
+            intervalLabel, intervalField,
+            scriptLabel, scriptArea
+        );
+        
+        dialog.getDialogPane().setContent(mainContainer);
+        dialog.getDialogPane().getButtonTypes().addAll(ButtonType.OK, ButtonType.CANCEL);
+        
+        // Validation and conversion
+        dialog.setResultConverter(buttonType -> {
+            if (buttonType == ButtonType.OK) {
+                String name = nameField.getText();
+                if (name == null || name.trim().isEmpty()) {
+                    showAlert("Validation Error", "Name is required", "Please enter a name for the action.");
+                    return null;
+                }
+                
+                String script = scriptArea.getText();
+                if (script == null || script.trim().isEmpty()) {
+                    showAlert("Validation Error", "Script is required", "Please enter JavaScript code.");
+                    return null;
+                }
+                
+                NodeAction action = new NodeAction();
+                action.setNodeId(nodeRow.getNodeId());
+                action.setActionName(name.trim());
+                action.setTriggerType(triggerCombo.getValue());
+                action.setScript(script);
+                action.setTriggerValue(triggerValueField.getText());
+                
+                try {
+                    action.setIntervalMs(Integer.parseInt(intervalField.getText()));
+                } catch (NumberFormatException ex) {
+                    action.setIntervalMs(1000);
+                }
+                
+                return action;
+            }
+            return null;
+        });
+        
+        // Set initial focus
+        javafx.application.Platform.runLater(() -> nameField.requestFocus());
+        
+        return dialog.showAndWait().orElse(null);
+    }
+    
+    private void editAction(NodeAction action) {
+        Dialog<ButtonType> dialog = new Dialog<>();
+        dialog.setTitle("Edit Action");
+        dialog.setHeaderText("Edit: " + action.getActionName());
+        dialog.setResizable(true);
+        
+        VBox mainContainer = new VBox(15);
+        mainContainer.setPadding(new Insets(20));
+        mainContainer.setPrefWidth(600);
+        
+        Label nameLabel = new Label("Action Name:");
+        nameLabel.setStyle("-fx-font-weight: bold;");
+        TextField nameField = new TextField(action.getActionName());
+        nameField.setEditable(true);
+        nameField.setDisable(false);
+        
+        Label triggerLabel = new Label("Trigger Type:");
+        triggerLabel.setStyle("-fx-font-weight: bold;");
+        ComboBox<NodeAction.TriggerType> triggerCombo = new ComboBox<>();
+        triggerCombo.getItems().addAll(NodeAction.TriggerType.values());
+        triggerCombo.setValue(action.getTriggerType());
+        triggerCombo.setMaxWidth(Double.MAX_VALUE);
+        triggerCombo.setDisable(false);
+        
+        Label valueLabel = new Label("Trigger Value:");
+        TextField triggerValueField = new TextField(action.getTriggerValue() != null ? action.getTriggerValue() : "");
+        triggerValueField.setEditable(true);
+        
+        Label intervalLabel = new Label("Interval (ms):");
+        TextField intervalField = new TextField(String.valueOf(action.getIntervalMs()));
+        intervalField.setEditable(true);
+        
+        Label scriptLabel = new Label("JavaScript Code:");
+        scriptLabel.setStyle("-fx-font-weight: bold;");
+        TextArea scriptArea = new TextArea(action.getScript());
+        scriptArea.setPrefRowCount(12);
+        scriptArea.setWrapText(true);
+        scriptArea.setEditable(true);
+        scriptArea.setDisable(false);
+        VBox.setVgrow(scriptArea, Priority.ALWAYS);
+        
+        // Dynamic enabling
+        triggerCombo.valueProperty().addListener((obs, oldVal, newVal) -> {
+            if (newVal == null) return;
+            
+            boolean needsValue = newVal == NodeAction.TriggerType.ON_VALUE ||
+                                newVal == NodeAction.TriggerType.ON_GREATER_THAN ||
+                                newVal == NodeAction.TriggerType.ON_LESS_THAN;
+            triggerValueField.setDisable(!needsValue);
+            
+            boolean needsInterval = newVal == NodeAction.TriggerType.ON_INTERVAL;
+            intervalField.setDisable(!needsInterval);
+        });
+        
+        // Set initial state
+        NodeAction.TriggerType type = action.getTriggerType();
+        boolean needsValue = type == NodeAction.TriggerType.ON_VALUE ||
+                            type == NodeAction.TriggerType.ON_GREATER_THAN ||
+                            type == NodeAction.TriggerType.ON_LESS_THAN;
+        triggerValueField.setDisable(!needsValue);
+        
+        boolean needsInterval = type == NodeAction.TriggerType.ON_INTERVAL;
+        intervalField.setDisable(!needsInterval);
+        
+        mainContainer.getChildren().addAll(
+            nameLabel, nameField,
+            triggerLabel, triggerCombo,
+            valueLabel, triggerValueField,
+            intervalLabel, intervalField,
+            scriptLabel, scriptArea
+        );
+        
+        dialog.getDialogPane().setContent(mainContainer);
+        dialog.getDialogPane().getButtonTypes().addAll(ButtonType.OK, ButtonType.CANCEL);
+        
+        dialog.setResultConverter(buttonType -> {
+            if (buttonType == ButtonType.OK) {
+                action.setActionName(nameField.getText());
+                action.setTriggerType(triggerCombo.getValue());
+                action.setScript(scriptArea.getText());
+                action.setTriggerValue(triggerValueField.getText());
+                
+                try {
+                    action.setIntervalMs(Integer.parseInt(intervalField.getText()));
+                } catch (NumberFormatException ex) {
+                    // Keep existing
+                }
+            }
+            return buttonType;
+        });
+        
+        dialog.showAndWait();
+    }
+    
+    private void testAction(NodeAction action, NodeRow nodeRow) {
+        String currentValue = nodeRow.getValue();
+        if (currentValue == null || currentValue.isEmpty()) {
+            currentValue = "test-value";
+        }
+        
+        actionService.testAction(action.getNodeId(), action.getActionName(), currentValue);
+        
+        showAlert(
+            "Action Test",
+            "Testing: " + action.getActionName(),
+            "Action triggered with value: " + currentValue + "\n\n" +
+            "Check the log area below for script output (look for [JS] prefix)."
+        );
+    }
+    
+    private void updateScriptPrompt(TextArea scriptArea, NodeAction.TriggerType type) {
+        String prompt = switch (type) {
+            case ON_CHANGE -> "Triggered on any value change\n\nconsole.log('Value changed to:', currentValue);";
+            case ON_EVEN -> "Triggered when value is even\n\nconsole.log('Even value:', currentValue);";
+            case ON_ODD -> "Triggered when value is odd\n\nconsole.log('Odd value:', currentValue);";
+            case ON_GREATER_THAN -> "Triggered when value > threshold\n\nconsole.log('ALARM! Value too high:', currentValue);";
+            case ON_LESS_THAN -> "Triggered when value < threshold\n\nconsole.log('WARNING! Value too low:', currentValue);";
+            case ON_VALUE -> "Triggered when value equals specific value\n\nconsole.log('Target value reached:', currentValue);";
+            case ON_TRUE -> "Triggered when value becomes truthy\n\nconsole.log('Activated:', currentValue);";
+            case ON_FALSE -> "Triggered when value becomes falsy\n\nconsole.log('Deactivated:', currentValue);";
+            case ON_INTERVAL -> "Triggered periodically\n\nvar value = opc.read(nodeId);\nconsole.log('Periodic check:', value);";
+        };
+        
+        if (scriptArea.getText().isEmpty()) {
+            scriptArea.setPromptText(prompt);
+        }
+    }
+    
+    private void showAlert(String title, String header, String content) {
+        Alert alert = new Alert(Alert.AlertType.INFORMATION);
+        alert.setTitle(title);
+        alert.setHeaderText(header);
+        alert.setContentText(content);
+        alert.showAndWait();
+    }
+}
diff --git a/main/java/de/opcua/app/ui/ConfigController.java b/main/java/de/opcua/app/ui/ConfigController.java
new file mode 100644
index 0000000..fd4ba8c
--- /dev/null
+++ b/main/java/de/opcua/app/ui/ConfigController.java
@@ -0,0 +1,106 @@
+package de.opcua.app.ui;
+
+import de.opcua.app.config.Settings;
+import javafx.event.ActionEvent;
+import javafx.fxml.FXML;
+import javafx.scene.control.CheckBox;
+import javafx.scene.control.ComboBox;
+import javafx.scene.control.PasswordField;
+import javafx.scene.control.TextField;
+import javafx.stage.FileChooser;
+
+import java.io.File;
+import java.util.Optional;
+
+public class ConfigController {
+
+  @FXML private TextField endpointTextBox;
+  @FXML private TextField hostTextBox;
+  
+  // HTTP Configuration
+  @FXML private CheckBox httpEnabledCheckBox;
+  @FXML private TextField httpPortTextBox;
+  
+  // HTTPS Configuration
+  @FXML private CheckBox httpsEnabledCheckBox;
+  @FXML private TextField httpsPortTextBox;
+  @FXML private TextField keystorePathTextBox;
+  @FXML private PasswordField keystorePasswordTextBox;
+  @FXML private ComboBox<String> keystoreTypeComboBox;
+
+  private Settings initial;
+  private Settings updated;
+
+  public void setSettings(Settings s) {
+    this.initial = s;
+    if (endpointTextBox != null) endpointTextBox.setText(s.endpoint());
+    if (hostTextBox != null) hostTextBox.setText(s.host());
+    
+    // HTTP fields
+    if (httpEnabledCheckBox != null) httpEnabledCheckBox.setSelected(s.httpEnabled());
+    if (httpPortTextBox != null) httpPortTextBox.setText(String.valueOf(s.httpPort()));
+    
+    // HTTPS fields
+    if (httpsEnabledCheckBox != null) httpsEnabledCheckBox.setSelected(s.httpsEnabled());
+    if (httpsPortTextBox != null) httpsPortTextBox.setText(String.valueOf(s.httpsPort()));
+    if (keystorePathTextBox != null) keystorePathTextBox.setText(s.keystorePath());
+    if (keystorePasswordTextBox != null) keystorePasswordTextBox.setText(s.keystorePassword());
+    if (keystoreTypeComboBox != null) keystoreTypeComboBox.setValue(s.keystoreType());
+  }
+
+  @FXML
+  public void initialize() {
+    // Initialize ComboBox items if present
+    if (keystoreTypeComboBox != null) {
+      keystoreTypeComboBox.getItems().addAll("JKS", "PKCS12");
+      keystoreTypeComboBox.setValue("JKS");
+    }
+  }
+
+  @FXML
+  public void SaveButton_Click(ActionEvent e) {
+    try {
+      int httpPort = Integer.parseInt(httpPortTextBox.getText());
+      int httpsPort = Integer.parseInt(httpsPortTextBox.getText());
+      
+      updated = new Settings(
+          endpointTextBox.getText(),
+          hostTextBox.getText(),
+          httpEnabledCheckBox != null && httpEnabledCheckBox.isSelected(),
+          httpPort,
+          httpsEnabledCheckBox != null && httpsEnabledCheckBox.isSelected(),
+          httpsPort,
+          keystorePathTextBox != null ? keystorePathTextBox.getText() : "",
+          keystorePasswordTextBox != null ? keystorePasswordTextBox.getText() : "",
+          keystoreTypeComboBox != null ? keystoreTypeComboBox.getValue() : "JKS",
+          initial.scriptLoggingEnabled(),
+          initial.scriptLogLevel(),
+          initial.scriptLogDirectory()
+      );
+      
+      // Close window
+      endpointTextBox.getScene().getWindow().hide();
+    } catch (NumberFormatException ex) {
+      System.err.println("Invalid port number: " + ex.getMessage());
+    }
+  }
+  
+  @FXML
+  public void BrowseKeystore_Click(ActionEvent e) {
+    FileChooser fc = new FileChooser();
+    fc.setTitle("Select Keystore");
+    fc.getExtensionFilters().addAll(
+        new FileChooser.ExtensionFilter("Keystore Files", "*.jks", "*.p12", "*.pfx"),
+        new FileChooser.ExtensionFilter("All Files", "*.*")
+    );
+    
+    File file = fc.showOpenDialog(keystorePathTextBox.getScene().getWindow());
+    if (file != null) {
+        keystorePathTextBox.setText(file.getAbsolutePath());
+    }
+  }
+
+  public Optional<Settings> getUpdatedSettings() {
+    return Optional.ofNullable(updated);
+  }
+}
diff --git a/main/java/de/opcua/app/ui/EditableValueCellFactory.java b/main/java/de/opcua/app/ui/EditableValueCellFactory.java
new file mode 100644
index 0000000..dd9aec1
--- /dev/null
+++ b/main/java/de/opcua/app/ui/EditableValueCellFactory.java
@@ -0,0 +1,193 @@
+package de.opcua.app.ui;
+
+import de.opcua.app.model.NodeRow;
+import de.opcua.app.opc.OpcUaService;
+import javafx.scene.control.*;
+import javafx.scene.control.cell.TextFieldTableCell;
+import javafx.util.StringConverter;
+
+/**
+ * Makes the Value column editable with OPC UA write-back
+ */
+public class EditableValueCellFactory {
+    
+    private final OpcUaService opcService;
+    
+    public EditableValueCellFactory(OpcUaService opcService) {
+        this.opcService = opcService;
+    }
+    
+    /**
+     * Create editable value column
+     */
+    public TableColumn<NodeRow, String> createEditableValueColumn() {
+        TableColumn<NodeRow, String> col = new TableColumn<>("Value");
+        col.setCellValueFactory(c -> c.getValue().valueProperty());
+        col.setCellFactory(tc -> new EditableValueCell());
+        col.setEditable(true);
+        col.setPrefWidth(150);
+        col.setOnEditCommit(event -> handleValueEdit(event));
+        
+        return col;
+    }
+    
+    private void handleValueEdit(TableColumn.CellEditEvent<NodeRow, String> event) {
+        NodeRow row = event.getRowValue();
+        String newValue = event.getNewValue();
+        String oldValue = event.getOldValue();
+        
+        if (newValue == null || newValue.equals(oldValue)) {
+            return;
+        }
+        
+        // Attempt to write to OPC UA
+        if (!opcService.isConnected()) {
+            showError("Not connected to OPC UA server");
+            row.setValue(oldValue); // Revert
+            return;
+        }
+        
+        if (!row.isReadable()) {
+            showError("Node is not writable");
+            row.setValue(oldValue); // Revert
+            return;
+        }
+        
+        // Write to OPC UA
+        opcService.writeValue(row.getNodeId(), newValue)
+            .thenAccept(success -> {
+                javafx.application.Platform.runLater(() -> {
+                    if (success) {
+                        row.setValue(newValue);
+                        System.out.println("[OPC UA] Write successful: " + row.getNodeId() + " = " + newValue);
+                    } else {
+                        showError("Write failed for " + row.getNodeId());
+                        row.setValue(oldValue); // Revert
+                    }
+                });
+            })
+            .exceptionally(ex -> {
+                javafx.application.Platform.runLater(() -> {
+                    showError("Write error: " + ex.getMessage());
+                    row.setValue(oldValue); // Revert
+                });
+                return null;
+            });
+    }
+    
+    private void showError(String message) {
+        Alert alert = new Alert(Alert.AlertType.ERROR);
+        alert.setTitle("Write Error");
+        alert.setHeaderText("Failed to write value");
+        alert.setContentText(message);
+        alert.show();
+    }
+    
+    /**
+     * Custom editable cell with visual feedback
+     */
+    private class EditableValueCell extends TableCell<NodeRow, String> {
+        private TextField textField;
+        
+        public EditableValueCell() {
+            setConverter(new StringConverter<String>() {
+                @Override
+                public String toString(String object) {
+                    return object == null ? "" : object;
+                }
+                
+                @Override
+                public String fromString(String string) {
+                    return string;
+                }
+            });
+        }
+        
+        @Override
+        public void startEdit() {
+            NodeRow row = getTableRow().getItem();
+            if (row == null || !row.isReadable()) {
+                // Not editable - show tooltip
+                Tooltip tooltip = new Tooltip("This node is read-only");
+                setTooltip(tooltip);
+                return;
+            }
+            
+            if (!opcService.isConnected()) {
+                Tooltip tooltip = new Tooltip("Not connected to OPC UA");
+                setTooltip(tooltip);
+                return;
+            }
+            
+            super.startEdit();
+            
+            if (textField == null) {
+                createTextField();
+            }
+            
+            textField.setText(getItem());
+            setText(null);
+            setGraphic(textField);
+            textField.selectAll();
+            textField.requestFocus();
+        }
+        
+        @Override
+        public void cancelEdit() {
+            super.cancelEdit();
+            setText(getItem());
+            setGraphic(null);
+        }
+        
+        @Override
+        protected void updateItem(String item, boolean empty) {
+            super.updateItem(item, empty);
+            
+            if (empty) {
+                setText(null);
+                setGraphic(null);
+                setStyle("");
+            } else {
+                if (isEditing()) {
+                    if (textField != null) {
+                        textField.setText(getItem());
+                    }
+                    setText(null);
+                    setGraphic(textField);
+                } else {
+                    setText(item);
+                    setGraphic(null);
+                    
+                    // Visual indication of editability
+                    NodeRow row = getTableRow().getItem();
+                    if (row != null && row.isReadable() && opcService.isConnected()) {
+                        setStyle("-fx-background-color: #f0fff0;"); // Light green
+                        setTooltip(new Tooltip("Double-click to edit"));
+                    } else {
+                        setStyle("");
+                        setTooltip(null);
+                    }
+                }
+            }
+        }
+        
+        private void createTextField() {
+            textField = new TextField(getItem());
+            textField.setMinWidth(getWidth() - getGraphicTextGap() * 2);
+            
+            textField.setOnAction(event -> {
+                commitEdit(textField.getText());
+            });
+            
+            textField.focusedProperty().addListener((obs, wasFocused, isNowFocused) -> {
+                if (!isNowFocused) {
+                    commitEdit(textField.getText());
+                }
+            });
+        }
+        
+        private void setConverter(StringConverter<String> converter) {
+            // Helper method for future enhancements
+        }
+    }
+}
diff --git a/main/java/de/opcua/app/ui/MainController.java b/main/java/de/opcua/app/ui/MainController.java
new file mode 100644
index 0000000..26416fd
--- /dev/null
+++ b/main/java/de/opcua/app/ui/MainController.java
@@ -0,0 +1,759 @@
+package de.opcua.app.ui;
+
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.controller.ActionButtonHelper;
+import de.opcua.app.model.NodeRow;
+import de.opcua.app.model.TreeNodeRef;
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.scripting.ScriptService;
+import de.opcua.app.scripting.Store;
+import de.opcua.app.service.ActionService;
+import de.opcua.app.service.ActionPersistenceService;
+import de.opcua.app.rest.OpcUaRestApi;
+import javafx.animation.KeyFrame;
+import javafx.animation.Timeline;
+import javafx.application.Platform;
+import javafx.collections.*;
+import javafx.event.ActionEvent;
+import javafx.fxml.FXML;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Scene;
+import javafx.scene.control.*;
+import javafx.scene.control.cell.CheckBoxTableCell;
+import javafx.scene.layout.Pane;
+import javafx.stage.Modality;
+import javafx.stage.Stage;
+import javafx.util.Duration;
+
+import java.io.IOException;
+import java.util.Optional;
+import java.util.function.Consumer;
+import java.util.List;
+import java.util.Map;
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+
+public class MainController {
+
+    @FXML private Button connectButton;
+    @FXML private Button saveButton;
+    @FXML private Button settingsButton;
+
+    @FXML private TreeView<TreeNodeRef> myTreeView;
+    @FXML private TableView<NodeRow> nodeListview;
+
+    @FXML private TableColumn<NodeRow, Boolean> checkBoxColumn;
+    @FXML private TableColumn<NodeRow, String> colDisplayName;
+    @FXML private TableColumn<NodeRow, String> colNodeType;
+    @FXML private TableColumn<NodeRow, String> colNodeId;
+    @FXML private TableColumn<NodeRow, String> colNamespaceIndex;
+    @FXML private TableColumn<NodeRow, String> colIdentifierType;
+    @FXML private TableColumn<NodeRow, String> colValue;
+
+    @FXML private TextArea logArea;
+    @FXML private TextField scriptField;
+    @FXML private Button runScriptButton;
+
+    private final ObservableList<NodeRow> rows = FXCollections.observableArrayList();
+
+    private final SettingsService settingsService = new SettingsService();
+    private Settings settings;
+
+    private final OpcUaService opc = new OpcUaService();
+    private final Store store = new Store();
+    private ActionService actionService;
+    private ActionButtonHelper actionButtonHelper;
+    private ActionPersistenceService actionPersistence;
+    private OpcUaRestApi restApi;
+
+    private ScriptService scriptService;
+    private Timeline refreshTimer;
+
+    // ------------------------------------------------------------
+    // INIT
+    // ------------------------------------------------------------
+
+    @FXML
+    public void initialize() {
+        // KEIN try/catch → load() wirft keine IOException
+        settings = settingsService.load();
+
+        checkBoxColumn.setCellValueFactory(c -> c.getValue().selectedProperty());
+        checkBoxColumn.setCellFactory(CheckBoxTableCell.forTableColumn(checkBoxColumn));
+
+        colDisplayName.setCellValueFactory(c -> c.getValue().displayNameProperty());
+        colNodeType.setCellValueFactory(c -> c.getValue().nodeTypeProperty());
+        colNodeId.setCellValueFactory(c -> c.getValue().nodeIdProperty());
+        colNamespaceIndex.setCellValueFactory(c -> c.getValue().namespaceIndexProperty());
+        colIdentifierType.setCellValueFactory(c -> c.getValue().identifierTypeProperty());
+        
+        // ✅ Make value column EDITABLE
+        colValue.setCellValueFactory(c -> c.getValue().valueProperty());
+        colValue.setCellFactory(tc -> new EditableValueCell());
+        colValue.setEditable(true);
+        colValue.setOnEditCommit(event -> handleValueEdit(event));
+
+        nodeListview.setItems(rows);
+        nodeListview.getSelectionModel().setSelectionMode(SelectionMode.SINGLE);
+        nodeListview.setEditable(true);  // ✅ Table must be editable
+        checkBoxColumn.setEditable(true);
+
+        // ✅ Initialize ActionService and add Action Button Column
+        actionService = new ActionService(opc, store);
+        actionButtonHelper = new ActionButtonHelper(actionService);
+        
+        // Add the action button column to the table
+        TableColumn<NodeRow, Void> actionColumn = actionButtonHelper.createActionColumn();
+        nodeListview.getColumns().add(actionColumn);
+        
+        // ✅ Add DELETE button column
+        TableColumn<NodeRow, Void> deleteColumn = createDeleteColumn();
+        nodeListview.getColumns().add(deleteColumn);
+        
+        // ✅ Initialize persistence and load saved actions
+        actionPersistence = new ActionPersistenceService();
+        java.util.Map<String, java.util.List<NodeAction>> savedActions = actionPersistence.loadActions();
+        if (!savedActions.isEmpty()) {
+            actionService.importActionsFromList(savedActions);
+            log("Loaded " + savedActions.size() + " saved node configurations with actions");
+        }
+        
+        // ✅ Start auto-save (every 60 seconds)
+        actionPersistence.startAutoSave(actionService, 60);
+        log("Action buttons enabled - Auto-save active (every 60s)");
+        
+        // ✅ Start REST API - IMMEDIATELY in initialize (not deferred)
+        log("═══════════════════════════════════");
+        log("Starting HTTP API...");
+        log("═══════════════════════════════════");
+        
+        try {
+            if (!settings.httpEnabled()) {
+                log("HTTP disabled in settings.");
+            } else {
+                int port = settings.httpPort();
+                
+                log("HTTP Port from settings: " + port);
+                
+                log("Creating OpcUaRestApi on port " + port + "...");
+                restApi = new OpcUaRestApi(opc, port, actionService);
+                log("OpcUaRestApi instance created");
+                
+                log("Calling restApi.start()...");
+                restApi.start();
+                log("restApi.start() completed");
+                
+                log("✅✅✅ HTTP API STARTED SUCCESSFULLY! ✅✅✅");
+                log("🌐 Web Interface: http://localhost:" + port + "/");
+                log("📡 API Status: http://localhost:" + port + "/api/status");
+                log("═══════════════════════════════════");
+                
+                // Also print to console
+                System.out.println("\n\n");
+                System.out.println("╔═══════════════════════════════════════════╗");
+                System.out.println("║     🚀 HTTP API STARTED SUCCESSFULLY      ║");
+                System.out.println("╠═══════════════════════════════════════════╣");
+                System.out.println("║  Port: " + port + "                                  ║");
+                System.out.println("║  Web UI: http://localhost:" + port + "/           ║");
+                System.out.println("╚═══════════════════════════════════════════╝");
+               
+    
+
+            }
+            
+        } catch (Exception e) {
+            log("❌❌❌ HTTP API START FAILED! ❌❌❌");
+            log("Error type: " + e.getClass().getName());
+            log("Error message: " + e.getMessage());
+            
+            System.err.println("\n\n");
+            System.err.println("╔═══════════════════════════════════════════╗");
+            System.err.println("║     ❌ HTTP API START FAILED!             ║");
+            System.err.println("╚═══════════════════════════════════════════╝");
+            System.err.println("Error: " + e.getMessage());
+            System.err.println("\nFull stack trace:");
+            e.printStackTrace();
+            System.err.println("\n\n");
+        }
+
+        initScripting();
+        startRefreshTimer();
+
+        log("Loaded settings. Endpoint=" + settings.endpoint());
+    }
+
+    // ------------------------------------------------------------
+    // CONNECT / DISCONNECT
+    // ------------------------------------------------------------
+
+    @FXML
+    public void connectButton_Click(ActionEvent e) {
+        if (opc.isConnected()) {
+            doDisconnect();
+        } else {
+doConnect();
+    }
+
+    }
+
+    @FXML
+    public void onSave(ActionEvent event) {
+        log("Save clicked. Selected rows: " + rows.size());
+    }
+
+    @FXML
+    public void onSettings(ActionEvent event) {
+        try {
+            FXMLLoader loader =
+                    new FXMLLoader(getClass().getResource("/ui/config.fxml"));
+            Pane root = loader.load();   // ← IOException MUSS hier gefangen werden
+
+            ConfigController controller = loader.getController();
+            controller.setSettings(settings);
+
+            Stage dlg = new Stage();
+            dlg.setTitle("Configuration");
+            dlg.initModality(Modality.APPLICATION_MODAL);
+            dlg.setScene(new Scene(root, 800, 450));
+            dlg.showAndWait();
+
+        controller.getUpdatedSettings().ifPresent(s -> {
+    try {
+        settings = s;
+        settingsService.save(settings);
+        log("Settings saved. Endpoint=" + settings.endpoint());
+    } catch (IOException ex) {
+        alert("Fehler beim Speichern", ex.getMessage());
+    }
+});
+
+
+        } catch (IOException ex) {
+            alert("Settings Fehler", ex.getMessage());
+        }
+    }
+
+
+private void doConnect() {
+    connectButton.setDisable(true);
+    log("Connecting to " + settings.endpoint() + " ...");
+            System.err.println("Connecting to " + settings.endpoint() + " ...");
+
+    // ✅ opc.connect() selbst auf Background-Thread auslagern
+    CompletableFuture.supplyAsync(() -> opc.connect(settings.endpoint()))
+        .thenCompose(future -> future)  // unwrap das innere CompletableFuture
+        .whenCompleteAsync((v, ex) -> {
+            Platform.runLater(() -> {
+                connectButton.setDisable(false);
+
+                if (ex != null) {
+                    log("Connect failed: " + ex.getMessage());
+                    
+                    alert("Connect fehlgeschlagen", ex.toString());
+                } else {
+                    connectButton.setText("Disconnect");
+                    log("Connected.");
+                    System.err.println("Connected");
+
+                    loadOpcTree();
+                    buildDigitalTwinInBackground();
+                }
+            });
+        });
+}
+    /**
+     * Build complete OPC UA tree in background and cache it for API
+     */
+  
+   private void buildDigitalTwinInBackground() {
+    log("🔄 Building digital twin...");
+    
+    if (restApi != null) {
+        restApi.triggerDigitalTwinBuild();  // ✅ RestApi baut selbst, cached selbst
+        log("Digital twin build triggered via RestApi");
+        System.err.println("Digital twin build triggered via RestApi");
+
+        
+    } else {
+        log("⚠️ restApi is null - skipping");
+         System.err.println("restApi is null - skipping");
+
+    }
+}  
+    /**
+     * Browse OPC UA tree recursively for digital twin
+     */
+ private List<Map<String, Object>> browseTreeRecursive(String nodeId, int depth, int maxDepth) 
+        throws Exception {
+    if (depth >= maxDepth) return new ArrayList<>();
+
+    var childrenFuture = nodeId == null 
+        ? opc.browseRoot()
+        : opc.browse(nodeId);
+    
+    var children = childrenFuture.get(30, TimeUnit.SECONDS);
+    List<Map<String, Object>> result = new ArrayList<>();
+
+    for (var child : children) {
+        Map<String, Object> node = new HashMap<>();
+        
+        // ✅ Gleiche Keys wie OpcUaRestApi.browseRecursive()
+        node.put("nodeId",      child.nodeId());
+        node.put("displayName", child.displayName());
+        node.put("browseName",  child.browseName());
+        node.put("nodeClass",   child.nodeClass());
+        node.put("dataType",    child.dataType());
+        node.put("accessLevel", child.accessLevel());
+
+        // ✅ Wert nur für Variables lesen
+        if ("Variable".equals(child.nodeClass())) {
+            try {
+                String val = opc.readValue(child.nodeId()).get(5, TimeUnit.SECONDS);
+                node.put("value", val);
+            } catch (Exception e) {
+                node.put("value", null);
+            }
+        }
+
+        node.put("children", browseTreeRecursive(child.nodeId(), depth + 1, maxDepth));
+        result.add(node);
+    }
+    return result;
+}    
+    /**
+     * Count total nodes in tree
+     */
+    private int countTreeNodes(List<Map<String, Object>> tree) {
+        int count = tree.size();
+        for (var node : tree) {
+            @SuppressWarnings("unchecked")
+            List<Map<String, Object>> children = (List<Map<String, Object>>) node.get("children");
+            if (children != null && !children.isEmpty()) {
+                count += countTreeNodes(children);
+            }
+        }
+        return count;
+    }
+
+    private void doDisconnect() {
+        opc.disconnect();
+        myTreeView.setRoot(null);
+        connectButton.setText("Connect");
+        log("Disconnected.");
+    }
+
+    // ------------------------------------------------------------
+    // OPC UA TREE – ROOT + LAZY LOAD
+    // ------------------------------------------------------------
+
+    private void loadOpcTree() {
+        TreeItem<TreeNodeRef> uiRoot =
+                new TreeItem<>(new TreeNodeRef("OPC UA Server", ""));
+        uiRoot.setExpanded(true);
+        myTreeView.setRoot(uiRoot);
+
+        opc.browseRoot().whenComplete((roots, ex) ->
+            Platform.runLater(() -> {
+                if (ex != null) {
+                    log("Root browse error: " + ex.getMessage());
+                    return;
+                }
+
+                for (TreeNodeRef ref : roots) {
+                    TreeItem<TreeNodeRef> child = new TreeItem<>(ref);
+                    attachLazyLoader(child);
+                    uiRoot.getChildren().add(child);
+                }
+            })
+        );
+    }
+
+    private void attachLazyLoader(TreeItem<TreeNodeRef> item) {
+        item.getChildren().add(new TreeItem<>());
+
+        item.addEventHandler(TreeItem.branchExpandedEvent(), evt -> {
+
+            if (item.getChildren().size() != 1 ||
+                item.getChildren().get(0).getValue() != null) return;
+
+            item.getChildren().clear();
+
+            opc.browse(item.getValue().nodeId())
+               .whenComplete((children, ex) ->
+                   Platform.runLater(() -> {
+                       if (ex != null) {
+                           log("Browse error: " + ex.getMessage());
+                           return;
+                       }
+
+                       for (TreeNodeRef ref : children) {
+                           TreeItem<TreeNodeRef> child = new TreeItem<>(ref);
+                           attachLazyLoader(child);
+                           item.getChildren().add(child);
+                       }
+                   })
+               );
+        });
+    }
+
+    // ------------------------------------------------------------
+    // TREE → TABLE
+    // ------------------------------------------------------------
+
+    @FXML
+    public void myTreeView_AfterSelect() {
+        TreeItem<TreeNodeRef> item =
+                myTreeView.getSelectionModel().getSelectedItem();
+        if (item == null || item.getValue() == null) return;
+
+        TreeNodeRef ref = item.getValue();
+
+        if (rows.stream().anyMatch(r -> r.getNodeId().equals(ref.nodeId()))) return;
+
+        // ✅ Parse NodeId to extract namespace and identifier type
+        String namespaceIndex = "";
+        String identifierType = "";
+        
+        try {
+            org.eclipse.milo.opcua.stack.core.types.builtin.NodeId nid = 
+                org.eclipse.milo.opcua.stack.core.types.builtin.NodeId.parse(ref.nodeId());
+            
+            namespaceIndex = String.valueOf(nid.getNamespaceIndex());
+            
+            Object identifier = nid.getIdentifier();
+            if (identifier instanceof String) {
+                identifierType = "String";
+            } else if (identifier instanceof org.eclipse.milo.opcua.stack.core.types.builtin.unsigned.UInteger) {
+                identifierType = "UInteger";
+            } else if (identifier instanceof java.util.UUID) {
+                identifierType = "UUID";
+            } else if (identifier instanceof org.eclipse.milo.opcua.stack.core.types.builtin.ByteString) {
+                identifierType = "ByteString";
+            } else {
+                identifierType = identifier != null ? identifier.getClass().getSimpleName() : "Unknown";
+            }
+            
+            log("Parsed: ns=" + namespaceIndex + ", type=" + identifierType);
+            
+        } catch (Exception e) {
+            log("Could not parse NodeId: " + e.getMessage());
+        }
+
+        rows.add(new NodeRow(
+                true,
+                ref.displayName(),
+                "Variable",
+                ref.nodeId(),
+                namespaceIndex,    // ✅ Filled
+                identifierType,    // ✅ Filled
+                ""
+        ));
+
+        log("Added node: " + ref.nodeId());
+    }
+
+    // ------------------------------------------------------------
+    // SCRIPTING
+    // ------------------------------------------------------------
+
+    private void initScripting() {
+        scriptService = new ScriptService();
+
+        if (!scriptService.isAvailable()) {
+            runScriptButton.setDisable(true);
+            scriptField.setDisable(true);
+            log("Scripting deaktiviert");
+            return;
+        }
+
+        scriptService.put("store", store);
+        scriptService.put("settings", settings);
+        scriptService.put("opc", new JsOpcBridge(opc));
+        scriptService.put("log",
+                (Consumer<Object>) msg -> Platform.runLater(() -> log(String.valueOf(msg))));
+
+        log("Scripting aktiviert.");
+    }
+
+    @FXML
+    public void runScript(ActionEvent e) {
+        if (scriptService == null || !scriptService.isAvailable()) return;
+
+        String code = Optional.ofNullable(scriptField.getText()).orElse("").trim();
+        if (code.isEmpty()) return;
+
+        try {
+            Object result = scriptService.eval(code);
+            log("JS => " + result);
+        } catch (Exception ex) {
+            log("JS error: " + ex.getMessage());
+        }
+    }
+
+    // ------------------------------------------------------------
+    // REFRESH
+    // ------------------------------------------------------------
+
+    private void startRefreshTimer() {
+        refreshTimer =
+                new Timeline(new KeyFrame(Duration.seconds(1), e -> refreshTick()));
+        refreshTimer.setCycleCount(Timeline.INDEFINITE);
+        refreshTimer.play();
+    }
+
+private void refreshTick() {
+    for (NodeRow r : rows) {
+
+        if (!r.isSelected()) continue;
+        if (!r.isReadable()) continue;
+
+        String oldValue = r.getValue();
+        
+        opc.readValue(r.getNodeId())
+           .whenComplete((val, ex) ->
+               Platform.runLater(() -> {
+                   String newValue = (ex != null ? "<err>" : val);
+                   r.setValue(newValue);
+                   
+                   // ✅ Trigger actions on value change
+                   if (actionService != null && !newValue.equals(oldValue)) {
+                       actionService.processValueChange(r.getNodeId(), newValue);
+                   }
+               }));
+    }
+}
+
+
+
+
+    // ------------------------------------------------------------
+    // HELPERS
+    // ------------------------------------------------------------
+
+    private void log(String s) {
+        logArea.appendText(s + "\n");
+    }
+
+    private void alert(String title, String msg) {
+        Alert a = new Alert(Alert.AlertType.INFORMATION);
+        a.setTitle(title);
+        a.setHeaderText(title);
+        a.setContentText(msg);
+        a.showAndWait();
+    }
+    
+    // ------------------------------------------------------------
+    // DELETE COLUMN
+    // ------------------------------------------------------------
+    
+    private TableColumn<NodeRow, Void> createDeleteColumn() {
+        TableColumn<NodeRow, Void> deleteCol = new TableColumn<>("×");
+        deleteCol.setPrefWidth(50);
+        deleteCol.setMaxWidth(50);
+        deleteCol.setMinWidth(50);
+        deleteCol.setResizable(false);
+        
+        deleteCol.setCellFactory(col -> new TableCell<NodeRow, Void>() {
+            private final Button deleteButton = new Button("×");
+            
+            {
+                deleteButton.setStyle(
+                    "-fx-background-color: transparent; " +
+                    "-fx-text-fill: #ff3b30; " +
+                    "-fx-font-size: 18px; " +
+                    "-fx-font-weight: bold; " +
+                    "-fx-cursor: hand; " +
+                    "-fx-padding: 2px 8px;"
+                );
+                
+                deleteButton.setOnMouseEntered(e -> 
+                    deleteButton.setStyle(
+                        "-fx-background-color: rgba(255, 59, 48, 0.1); " +
+                        "-fx-text-fill: #ff3b30; " +
+                        "-fx-font-size: 18px; " +
+                        "-fx-font-weight: bold; " +
+                        "-fx-cursor: hand; " +
+                        "-fx-padding: 2px 8px; " +
+                        "-fx-background-radius: 4px;"
+                    )
+                );
+                
+                deleteButton.setOnMouseExited(e -> 
+                    deleteButton.setStyle(
+                        "-fx-background-color: transparent; " +
+                        "-fx-text-fill: #ff3b30; " +
+                        "-fx-font-size: 18px; " +
+                        "-fx-font-weight: bold; " +
+                        "-fx-cursor: hand; " +
+                        "-fx-padding: 2px 8px;"
+                    )
+                );
+                
+                deleteButton.setOnAction(event -> {
+                    NodeRow row = getTableRow().getItem();
+                    if (row != null) {
+                        Alert confirm = new Alert(Alert.AlertType.CONFIRMATION);
+                        confirm.setTitle("Remove Node");
+                        confirm.setHeaderText("Remove " + row.getDisplayName() + "?");
+                        confirm.setContentText("This will remove the node from monitoring.");
+                        
+                        Optional<ButtonType> result = confirm.showAndWait();
+                        if (result.isPresent() && result.get() == ButtonType.OK) {
+                            rows.remove(row);
+                            log("Removed node: " + row.getDisplayName());
+                        }
+                    }
+                });
+            }
+            
+            @Override
+            protected void updateItem(Void item, boolean empty) {
+                super.updateItem(item, empty);
+                if (empty) {
+                    setGraphic(null);
+                } else {
+                    setGraphic(deleteButton);
+                }
+            }
+        });
+        
+        return deleteCol;
+    }
+    
+    // ------------------------------------------------------------
+    // EDITABLE VALUE COLUMN
+    // ------------------------------------------------------------
+    
+    private void handleValueEdit(TableColumn.CellEditEvent<NodeRow, String> event) {
+        NodeRow row = event.getRowValue();
+        String newValue = event.getNewValue();
+        String oldValue = event.getOldValue();
+        
+        if (newValue == null || newValue.equals(oldValue)) {
+            return;
+        }
+        
+        if (!opc.isConnected()) {
+            alert("Write Error", "Not connected to OPC UA server");
+            row.setValue(oldValue);
+            return;
+        }
+        
+        if (!row.isReadable()) {
+            alert("Write Error", "Node is not writable");
+            row.setValue(oldValue);
+            return;
+        }
+        
+        log("Writing " + newValue + " to " + row.getNodeId());
+        
+        opc.writeValue(row.getNodeId(), newValue)
+            .thenAccept(success -> Platform.runLater(() -> {
+                if (success) {
+                    row.setValue(newValue);
+                    log("✅ Write successful: " + row.getNodeId() + " = " + newValue);
+                } else {
+                    alert("Write Failed", "Failed to write value to " + row.getNodeId());
+                    row.setValue(oldValue);
+                }
+            }))
+            .exceptionally(ex -> {
+                Platform.runLater(() -> {
+                    alert("Write Error", "Error: " + ex.getMessage());
+                    row.setValue(oldValue);
+                });
+                return null;
+            });
+    }
+    
+    private class EditableValueCell extends TableCell<NodeRow, String> {
+        private TextField textField;
+        
+        @Override
+        public void startEdit() {
+            NodeRow row = getTableRow().getItem();
+            if (row == null || !row.isReadable()) {
+                return;
+            }
+            
+            if (!opc.isConnected()) {
+                return;
+            }
+            
+            super.startEdit();
+            
+            if (textField == null) {
+                createTextField();
+            }
+            
+            textField.setText(getItem());
+            setText(null);
+            setGraphic(textField);
+            textField.selectAll();
+            textField.requestFocus();
+        }
+        
+        @Override
+        public void cancelEdit() {
+            super.cancelEdit();
+            setText(getItem());
+            setGraphic(null);
+        }
+        
+        @Override
+        protected void updateItem(String item, boolean empty) {
+            super.updateItem(item, empty);
+            
+            if (empty) {
+                setText(null);
+                setGraphic(null);
+                setStyle("");
+            } else {
+                if (isEditing()) {
+                    if (textField != null) {
+                        textField.setText(getItem());
+                    }
+                    setText(null);
+                    setGraphic(textField);
+                } else {
+                    setText(item);
+                    setGraphic(null);
+                    
+                    NodeRow row = getTableRow().getItem();
+                    if (row != null && row.isReadable() && opc.isConnected()) {
+                        setStyle("-fx-background-color: #e8f5e9;");
+                        setTooltip(new Tooltip("Double-click to edit"));
+                    } else {
+                        setStyle("");
+                    }
+                }
+            }
+        }
+        
+        private void createTextField() {
+            textField = new TextField(getItem());
+            textField.setMinWidth(getWidth() - getGraphicTextGap() * 2);
+            
+            textField.setOnAction(evt -> commitEdit(textField.getText()));
+            
+            textField.focusedProperty().addListener((obs, was, is) -> {
+                if (!is) {
+                    commitEdit(textField.getText());
+                }
+            });
+        }
+    }
+
+    public static final class JsOpcBridge {
+        private final OpcUaService opc;
+        public JsOpcBridge(OpcUaService opc) { this.opc = opc; }
+        public boolean isConnected() { return opc.isConnected(); }
+    }
+
+
+  }
+
diff --git a/main/resources/styles/application.css b/main/resources/styles/application.css
new file mode 100644
index 0000000..a51fe79
--- /dev/null
+++ b/main/resources/styles/application.css
@@ -0,0 +1,401 @@
+/* OPCUA GUI Stylesheet */
+/* Place this in src/main/resources/styles/application.css */
+
+/* ============================================================================
+   ROOT & GENERAL
+   ============================================================================ */
+.root {
+    -fx-font-family: "Segoe UI", Arial, sans-serif;
+    -fx-font-size: 13px;
+    -fx-base: #f4f4f4;
+    -fx-background: #ffffff;
+}
+
+/* ============================================================================
+   ACTION BUTTONS
+   ============================================================================ */
+.action-button {
+    -fx-background-color: linear-gradient(to bottom, #4CAF50, #45a049);
+    -fx-text-fill: white;
+    -fx-font-weight: bold;
+    -fx-padding: 5 15 5 15;
+    -fx-border-radius: 4;
+    -fx-background-radius: 4;
+    -fx-cursor: hand;
+}
+
+.action-button:hover {
+    -fx-background-color: linear-gradient(to bottom, #45a049, #3d8b40);
+    -fx-effect: dropshadow(gaussian, rgba(0,0,0,0.3), 4, 0, 0, 1);
+}
+
+.action-button:pressed {
+    -fx-background-color: #3d8b40;
+    -fx-effect: innershadow(gaussian, rgba(0,0,0,0.3), 4, 0, 0, 1);
+}
+
+.action-button:disabled {
+    -fx-opacity: 0.5;
+    -fx-cursor: default;
+}
+
+/* ============================================================================
+   TABLE VIEW
+   ============================================================================ */
+.table-view {
+    -fx-background-color: transparent;
+    -fx-table-cell-border-color: transparent;
+}
+
+.table-view .column-header {
+    -fx-background-color: linear-gradient(to bottom, #e0e0e0, #d0d0d0);
+    -fx-font-weight: bold;
+    -fx-padding: 5;
+}
+
+.table-view .column-header-background {
+    -fx-background-color: #e0e0e0;
+}
+
+.table-row-cell {
+    -fx-border-color: transparent;
+    -fx-border-width: 0;
+}
+
+.table-row-cell:selected {
+    -fx-background-color: #e3f2fd;
+    -fx-table-cell-border-color: #2196F3;
+}
+
+.table-row-cell:hover {
+    -fx-background-color: #f5f5f5;
+}
+
+.table-row-cell:selected:hover {
+    -fx-background-color: #bbdefb;
+}
+
+/* Checkbox column styling */
+.check-box-table-cell .check-box {
+    -fx-cursor: hand;
+}
+
+/* ============================================================================
+   TREE VIEW
+   ============================================================================ */
+.tree-view {
+    -fx-background-color: white;
+    -fx-border-color: #d0d0d0;
+    -fx-border-width: 1;
+}
+
+.tree-cell {
+    -fx-padding: 2 5 2 5;
+}
+
+.tree-cell:selected {
+    -fx-background-color: #2196F3;
+    -fx-text-fill: white;
+}
+
+.tree-cell:hover {
+    -fx-background-color: #e3f2fd;
+}
+
+/* ============================================================================
+   BUTTONS
+   ============================================================================ */
+.button {
+    -fx-background-color: linear-gradient(to bottom, #f0f0f0, #d0d0d0);
+    -fx-border-color: #a0a0a0;
+    -fx-border-width: 1;
+    -fx-border-radius: 3;
+    -fx-background-radius: 3;
+    -fx-padding: 5 15 5 15;
+    -fx-cursor: hand;
+}
+
+.button:hover {
+    -fx-background-color: linear-gradient(to bottom, #e0e0e0, #c0c0c0);
+    -fx-border-color: #808080;
+}
+
+.button:pressed {
+    -fx-background-color: #c0c0c0;
+}
+
+.button:disabled {
+    -fx-opacity: 0.6;
+    -fx-cursor: default;
+}
+
+/* Primary button style */
+.button-primary {
+    -fx-background-color: linear-gradient(to bottom, #2196F3, #1976D2);
+    -fx-text-fill: white;
+    -fx-font-weight: bold;
+}
+
+.button-primary:hover {
+    -fx-background-color: linear-gradient(to bottom, #1976D2, #1565C0);
+}
+
+/* Danger button style */
+.button-danger {
+    -fx-background-color: linear-gradient(to bottom, #f44336, #d32f2f);
+    -fx-text-fill: white;
+}
+
+.button-danger:hover {
+    -fx-background-color: linear-gradient(to bottom, #d32f2f, #c62828);
+}
+
+/* Success button style */
+.button-success {
+    -fx-background-color: linear-gradient(to bottom, #4CAF50, #388E3C);
+    -fx-text-fill: white;
+}
+
+.button-success:hover {
+    -fx-background-color: linear-gradient(to bottom, #388E3C, #2E7D32);
+}
+
+/* ============================================================================
+   TEXT FIELDS & AREAS
+   ============================================================================ */
+.text-field, .text-area {
+    -fx-background-color: white;
+    -fx-border-color: #c0c0c0;
+    -fx-border-width: 1;
+    -fx-border-radius: 3;
+    -fx-background-radius: 3;
+    -fx-padding: 5;
+}
+
+.text-field:focused, .text-area:focused {
+    -fx-border-color: #2196F3;
+    -fx-border-width: 2;
+}
+
+.text-area {
+    -fx-font-family: "Consolas", "Monaco", "Courier New", monospace;
+    -fx-font-size: 12px;
+}
+
+/* ============================================================================
+   DIALOGS
+   ============================================================================ */
+.dialog-pane {
+    -fx-background-color: white;
+    -fx-padding: 10;
+}
+
+.dialog-pane .header-panel {
+    -fx-background-color: linear-gradient(to bottom, #e0e0e0, #d0d0d0);
+    -fx-padding: 10;
+}
+
+.dialog-pane .content {
+    -fx-padding: 20;
+}
+
+.dialog-pane .button-bar .button {
+    -fx-min-width: 80;
+}
+
+/* ============================================================================
+   COMBO BOX
+   ============================================================================ */
+.combo-box {
+    -fx-background-color: white;
+    -fx-border-color: #c0c0c0;
+    -fx-border-width: 1;
+    -fx-border-radius: 3;
+    -fx-background-radius: 3;
+}
+
+.combo-box:focused {
+    -fx-border-color: #2196F3;
+    -fx-border-width: 2;
+}
+
+.combo-box-popup .list-view {
+    -fx-background-color: white;
+    -fx-border-color: #2196F3;
+    -fx-border-width: 1;
+}
+
+.combo-box-popup .list-cell {
+    -fx-padding: 5;
+}
+
+.combo-box-popup .list-cell:hover {
+    -fx-background-color: #e3f2fd;
+}
+
+/* ============================================================================
+   LIST VIEW
+   ============================================================================ */
+.list-view {
+    -fx-background-color: white;
+    -fx-border-color: #d0d0d0;
+    -fx-border-width: 1;
+}
+
+.list-cell {
+    -fx-padding: 5;
+}
+
+.list-cell:selected {
+    -fx-background-color: #2196F3;
+    -fx-text-fill: white;
+}
+
+.list-cell:hover {
+    -fx-background-color: #e3f2fd;
+}
+
+/* ============================================================================
+   CHECK BOX
+   ============================================================================ */
+.check-box {
+    -fx-cursor: hand;
+}
+
+.check-box:selected .box {
+    -fx-background-color: #2196F3;
+    -fx-border-color: #1976D2;
+}
+
+/* ============================================================================
+   LABELS
+   ============================================================================ */
+.label {
+    -fx-text-fill: #333333;
+}
+
+.label-header {
+    -fx-font-size: 16px;
+    -fx-font-weight: bold;
+    -fx-text-fill: #1976D2;
+}
+
+.label-error {
+    -fx-text-fill: #d32f2f;
+    -fx-font-weight: bold;
+}
+
+.label-success {
+    -fx-text-fill: #388E3C;
+    -fx-font-weight: bold;
+}
+
+.label-warning {
+    -fx-text-fill: #F57C00;
+    -fx-font-weight: bold;
+}
+
+/* ============================================================================
+   PROGRESS INDICATOR
+   ============================================================================ */
+.progress-indicator {
+    -fx-progress-color: #2196F3;
+}
+
+/* ============================================================================
+   SEPARATOR
+   ============================================================================ */
+.separator {
+    -fx-background-color: #d0d0d0;
+}
+
+/* ============================================================================
+   SCROLL BAR
+   ============================================================================ */
+.scroll-bar {
+    -fx-background-color: transparent;
+}
+
+.scroll-bar .thumb {
+    -fx-background-color: #c0c0c0;
+    -fx-background-radius: 5;
+}
+
+.scroll-bar .thumb:hover {
+    -fx-background-color: #a0a0a0;
+}
+
+.scroll-bar .increment-button,
+.scroll-bar .decrement-button {
+    -fx-background-color: transparent;
+}
+
+/* ============================================================================
+   CUSTOM CLASSES
+   ============================================================================ */
+
+/* Action list item in dialog */
+.action-list-item {
+    -fx-padding: 5;
+    -fx-border-color: #e0e0e0;
+    -fx-border-width: 0 0 1 0;
+}
+
+.action-list-item:hover {
+    -fx-background-color: #f5f5f5;
+}
+
+/* Script editor */
+.script-editor {
+    -fx-font-family: "Consolas", "Monaco", "Courier New", monospace;
+    -fx-font-size: 12px;
+    -fx-background-color: #f8f8f8;
+    -fx-border-color: #2196F3;
+    -fx-border-width: 2;
+    -fx-padding: 10;
+}
+
+/* Status indicator */
+.status-connected {
+    -fx-background-color: #4CAF50;
+    -fx-background-radius: 50%;
+    -fx-min-width: 12;
+    -fx-min-height: 12;
+    -fx-max-width: 12;
+    -fx-max-height: 12;
+}
+
+.status-disconnected {
+    -fx-background-color: #f44336;
+    -fx-background-radius: 50%;
+    -fx-min-width: 12;
+    -fx-min-height: 12;
+    -fx-max-width: 12;
+    -fx-max-height: 12;
+}
+
+/* Tooltip */
+.tooltip {
+    -fx-background-color: #333333;
+    -fx-text-fill: white;
+    -fx-padding: 5 10 5 10;
+    -fx-background-radius: 4;
+    -fx-font-size: 12px;
+}
+
+/* Badge for action count */
+.badge {
+    -fx-background-color: #2196F3;
+    -fx-text-fill: white;
+    -fx-background-radius: 10;
+    -fx-padding: 2 6 2 6;
+    -fx-font-size: 10px;
+    -fx-font-weight: bold;
+}
+
+/* Grid pane for forms */
+.form-grid {
+    -fx-hgap: 10;
+    -fx-vgap: 10;
+    -fx-padding: 10;
+}
diff --git a/main/resources/styles/opcua-simulator-icon.png b/main/resources/styles/opcua-simulator-icon.png
new file mode 100644
index 0000000..2a339b7
Binary files /dev/null and b/main/resources/styles/opcua-simulator-icon.png differ
diff --git a/main/resources/ui/config.fxml b/main/resources/ui/config.fxml
new file mode 100644
index 0000000..5a60819
--- /dev/null
+++ b/main/resources/ui/config.fxml
@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.*?>
+<?import javafx.scene.layout.*?>
+
+<AnchorPane xmlns="http://javafx.com/javafx/21" xmlns:fx="http://javafx.com/fxml/1"
+            fx:controller="de.opcua.app.ui.ConfigController"
+            prefWidth="800" prefHeight="600">
+
+  <Label text="OPC UA Server" layoutX="139" layoutY="40"/>
+  <TextField fx:id="endpointTextBox" layoutX="250" layoutY="37" prefWidth="400" prefHeight="25"/>
+
+  <Label text="Host" layoutX="192" layoutY="70"/>
+  <TextField fx:id="hostTextBox" layoutX="250" layoutY="67" prefWidth="400" prefHeight="25"/>
+
+  <!-- HTTP Configuration -->
+  <Separator layoutX="139" layoutY="105" prefWidth="520"/>
+  <Label text="HTTP Configuration" layoutX="139" layoutY="115" style="-fx-font-weight: bold; -fx-font-size: 14px;"/>
+  
+  <CheckBox fx:id="httpEnabledCheckBox" text="Enable HTTP" layoutX="139" layoutY="145"/>
+  
+  <Label text="HTTP Port" layoutX="165" layoutY="175"/>
+  <TextField fx:id="httpPortTextBox" layoutX="250" layoutY="172" prefWidth="100" prefHeight="25"/>
+  <Label text="(e.g., 8081)" layoutX="360" layoutY="175" style="-fx-text-fill: #888;"/>
+
+  <!-- HTTPS Configuration -->
+  <Separator layoutX="139" layoutY="215" prefWidth="520"/>
+  <Label text="HTTPS Configuration" layoutX="139" layoutY="225" style="-fx-font-weight: bold; -fx-font-size: 14px;"/>
+  
+  <CheckBox fx:id="httpsEnabledCheckBox" text="Enable HTTPS" layoutX="139" layoutY="255"/>
+  
+  <Label text="HTTPS Port" layoutX="157" layoutY="285"/>
+  <TextField fx:id="httpsPortTextBox" layoutX="250" layoutY="282" prefWidth="100" prefHeight="25"/>
+  <Label text="(e.g., 8443)" layoutX="360" layoutY="285" style="-fx-text-fill: #888;"/>
+  
+  <Label text="Certificate (Keystore)" layoutX="110" layoutY="315"/>
+  <TextField fx:id="keystorePathTextBox" layoutX="250" layoutY="312" prefWidth="320" prefHeight="25"/>
+  <Button text="Browse..." layoutX="580" layoutY="312" prefWidth="75" onAction="#BrowseKeystore_Click"/>
+  
+  <Label text="Keystore Password" layoutX="125" layoutY="345"/>
+  <PasswordField fx:id="keystorePasswordTextBox" layoutX="250" layoutY="342" prefWidth="400" prefHeight="25"/>
+  
+  <Label text="Keystore Type" layoutX="145" layoutY="375"/>
+  <ComboBox fx:id="keystoreTypeComboBox" layoutX="250" layoutY="372" prefWidth="150"/>
+
+  <!-- Buttons -->
+  <Separator layoutX="139" layoutY="415" prefWidth="520"/>
+  
+  <Button text="Save" layoutX="250" layoutY="435" prefWidth="100" prefHeight="35" onAction="#SaveButton_Click" 
+          style="-fx-background-color: #007aff; -fx-text-fill: white; -fx-font-weight: bold;"/>
+  <Button text="Cancel" layoutX="360" layoutY="435" prefWidth="100" prefHeight="35" onAction="#SaveButton_Click"
+          style="-fx-background-color: #8e8e93; -fx-text-fill: white;"/>
+</AnchorPane>
+
diff --git a/main/resources/ui/main.fxml b/main/resources/ui/main.fxml
new file mode 100644
index 0000000..3edf08b
--- /dev/null
+++ b/main/resources/ui/main.fxml
@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.control.*?>
+<?import javafx.scene.layout.*?>
+
+<AnchorPane  xmlns:fx="http://javafx.com/fxml"
+            fx:controller="de.opcua.app.ui.MainController"
+            prefWidth="1262" prefHeight="619">
+  <!-- Top buttons at y=12, x=30 -->
+  <Button fx:id="connectButton" text="Connect" layoutX="30" layoutY="12" prefWidth="78" prefHeight="23"
+          onAction="#connectButton_Click"/>
+  <Button fx:id="saveButton" text="Save" layoutX="114" layoutY="12" prefWidth="80" prefHeight="23"
+          onAction="#onSave"/>
+  <Button fx:id="settingsButton" text="Settings" layoutX="200" layoutY="12" prefWidth="75" prefHeight="23"
+          onAction="#onSettings"/>
+
+  <!-- TreeView at (30,50) size (200,540) -->
+  <TreeView fx:id="myTreeView" layoutX="30" layoutY="50" prefWidth="200" prefHeight="540"
+            onMouseClicked="#myTreeView_AfterSelect"/>
+
+  <!-- Data table at (276,25) size approx (913,540) -->
+  <TableView fx:id="nodeListview" layoutX="276" layoutY="25" prefWidth="913" prefHeight="540">
+    <columns>
+      <TableColumn fx:id="checkBoxColumn" text="Select" prefWidth="70"/>
+      <TableColumn fx:id="colDisplayName" text="DisplayName" prefWidth="160"/>
+      <TableColumn fx:id="colNodeType" text="NodeType" prefWidth="110"/>
+      <TableColumn fx:id="colNodeId" text="NodeId" prefWidth="240"/>
+      <TableColumn fx:id="colNamespaceIndex" text="NamespaceIndex" prefWidth="120"/>
+      <TableColumn fx:id="colIdentifierType" text="IdentifierType" prefWidth="120"/>
+      <TableColumn fx:id="colValue" text="Value" prefWidth="120"/>
+    </columns>
+  </TableView>
+
+  <!-- Bottom scripting + log (extra, not in WinForms, but useful; can be removed) -->
+  <Label text="JS:" layoutX="276" layoutY="575"/>
+  <TextField fx:id="scriptField" layoutX="306" layoutY="571" prefWidth="770" prefHeight="23"/>
+  <Button fx:id="runScriptButton" text="Run" layoutX="1085" layoutY="571" prefWidth="55" prefHeight="23"
+          onAction="#runScript"/>
+
+  <TextArea fx:id="logArea" layoutX="30" layoutY="595" prefWidth="1159" prefHeight="0" visible="false"/>
+</AnchorPane>
diff --git a/main/resources/web/web-interface.html b/main/resources/web/web-interface.html
new file mode 100644
index 0000000..8b4d649
--- /dev/null
+++ b/main/resources/web/web-interface.html
@@ -0,0 +1,636 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
+    <meta name="mobile-web-app-capable" content="yes">
+    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
+    <meta name="theme-color" content="#007aff" media="(prefers-color-scheme: light)">
+    <meta name="theme-color" content="#0a0a0a" media="(prefers-color-scheme: dark)">
+    <title>OPC UA Control</title>
+    <style>
+        :root {
+            --bg-primary: #f2f2f7;
+            --bg-secondary: #ffffff;
+            --bg-tertiary: #f2f2f7;
+            --text-primary: #1c1c1e;
+            --text-secondary: #8e8e93;
+            --border-color: rgba(60,60,67,0.18);
+            --blue: #007aff;
+            --green: #34c759;
+            --red: #ff3b30;
+            --orange: #ff9500;
+            --shadow: 0 1px 3px rgba(0,0,0,0.08);
+        }
+        @media (prefers-color-scheme: dark) {
+            :root {
+                --bg-primary: #000000;
+                --bg-secondary: #1c1c1e;
+                --bg-tertiary: #2c2c2e;
+                --text-primary: #ffffff;
+                --text-secondary: #98989d;
+                --border-color: rgba(84,84,88,0.48);
+                --shadow: 0 1px 3px rgba(0,0,0,0.3);
+            }
+        }
+        * { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
+        body { font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', Arial, sans-serif; background: var(--bg-primary); color: var(--text-primary); }
+        .header { background: var(--blue); color: white; padding: max(env(safe-area-inset-top), 20px) 20px 20px 20px; box-shadow: 0 2px 10px rgba(0,0,0,0.2); position: sticky; top: 0; z-index: 100; }
+        .header h1 { font-size: clamp(20px, 5vw, 28px); font-weight: 700; margin-bottom: 8px; }
+        .status-badge { display: inline-flex; align-items: center; gap: 6px; background: rgba(255,255,255,0.2); padding: 6px 12px; border-radius: 20px; font-size: 13px; font-weight: 600; }
+        .status-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--red); }
+        .status-dot.connected { background: var(--green); animation: pulse 2s infinite; }
+        @keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.6; } }
+        .toolbar { background: var(--bg-secondary); padding: 12px 20px; border-bottom: 0.5px solid var(--border-color); display: flex; gap: 8px; overflow-x: auto; -webkit-overflow-scrolling: touch; align-items: center; }
+        .toolbar::-webkit-scrollbar { display: none; }
+        .btn { background: var(--blue); color: white; border: none; padding: 10px 16px; border-radius: 10px; font-size: 15px; font-weight: 600; cursor: pointer; transition: all 0.2s; white-space: nowrap; touch-action: manipulation; }
+        .btn:active { transform: scale(0.96); }
+        .btn-success { background: var(--green); }
+        .btn-danger { background: var(--red); }
+        .btn-secondary { background: var(--text-secondary); }
+        .btn-small { padding: 6px 12px; font-size: 13px; border-radius: 8px; }
+        .btn:disabled { opacity: 0.5; cursor: not-allowed; }
+        .twin-status { font-size: 12px; color: var(--text-secondary); white-space: nowrap; }
+        .container { max-width: 1600px; margin: 0 auto; padding: clamp(12px, 2vw, 20px); padding-bottom: max(env(safe-area-inset-bottom), 16px); }
+        .grid { display: grid; grid-template-columns: 1fr; gap: 16px; }
+        @media (min-width: 768px) { .grid { grid-template-columns: 350px 1fr; } }
+        @media (min-width: 1024px) { .grid { grid-template-columns: 400px 1fr; } }
+        .card { background: var(--bg-secondary); border-radius: 12px; margin-bottom: 16px; box-shadow: var(--shadow); overflow: hidden; }
+        .card-header { padding: 16px; border-bottom: 0.5px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
+        .card-title { font-size: 17px; font-weight: 600; }
+        .tree-container { max-height: 70vh; overflow-y: auto; -webkit-overflow-scrolling: touch; }
+        @media (min-width: 768px) { .tree-container { max-height: 600px; } }
+        .tree-node { padding: 10px 16px; border-bottom: 0.5px solid var(--border-color); cursor: pointer; user-select: none; }
+        .tree-node:active { background: var(--bg-tertiary); }
+        .tree-node-content { display: flex; align-items: center; gap: 8px; }
+        .tree-expand { width: 24px; height: 24px; border-radius: 50%; background: var(--bg-tertiary); display: flex; align-items: center; justify-content: center; font-size: 14px; transition: transform 0.2s; flex-shrink: 0; cursor: pointer; }
+        .tree-expand.expanded { transform: rotate(90deg); }
+        .tree-expand.loading-spin { animation: spin 0.7s linear infinite; }
+        .tree-children { padding-left: 28px; display: none; }
+        .tree-children.show { display: block; }
+        .value-badge { margin-left: 8px; padding: 2px 8px; background: var(--blue); color: white; border-radius: 6px; font-size: 11px; font-weight: 600; font-family: 'SF Mono', Monaco, monospace; }
+        .table-container { overflow-x: auto; -webkit-overflow-scrolling: touch; }
+        table { width: 100%; border-collapse: collapse; font-size: clamp(13px, 2vw, 15px); }
+        thead { background: var(--bg-tertiary); position: sticky; top: 0; z-index: 1; }
+        th { padding: 12px 8px; text-align: left; font-weight: 600; font-size: 13px; color: var(--text-secondary); text-transform: uppercase; border-bottom: 0.5px solid var(--border-color); white-space: nowrap; }
+        td { padding: 12px 8px; border-bottom: 0.5px solid var(--border-color); }
+        .value-cell { font-family: 'SF Mono', Monaco, 'Courier New', monospace; font-size: 14px; font-weight: 500; background: var(--bg-tertiary); padding: 6px 10px; border-radius: 6px; display: inline-block; cursor: pointer; transition: background 0.3s; }
+        .value-cell.updating { animation: highlight 0.5s; }
+        @keyframes highlight { 0%, 100% { background: var(--bg-tertiary); } 50% { background: var(--orange); } }
+        .modal { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.5); z-index: 1000; }
+        .modal.active { display: flex; align-items: flex-end; justify-content: center; }
+        @media (min-width: 768px) { .modal.active { align-items: center; } }
+        .modal-content { background: var(--bg-secondary); border-radius: 12px 12px 0 0; padding: 24px; max-width: 600px; width: 100%; max-height: 85vh; overflow-y: auto; }
+        @media (min-width: 768px) { .modal-content { border-radius: 12px; } }
+        .modal-header { font-size: 20px; font-weight: 700; margin-bottom: 20px; }
+        .form-group { margin-bottom: 16px; }
+        .form-label { display: block; margin-bottom: 8px; font-size: 13px; font-weight: 600; color: var(--text-secondary); text-transform: uppercase; }
+        .form-input, .form-select, .form-textarea { width: 100%; padding: 12px; border: 0.5px solid var(--border-color); border-radius: 10px; font-size: 16px; background: var(--bg-tertiary); color: var(--text-primary); transition: all 0.2s; }
+        .form-input:focus, .form-select:focus, .form-textarea:focus { outline: none; border-color: var(--blue); box-shadow: 0 0 0 4px rgba(0,122,255,0.1); }
+        .form-textarea { min-height: 120px; font-family: 'SF Mono', Monaco, monospace; resize: vertical; }
+        .badge { display: inline-block; padding: 4px 8px; background: var(--blue); color: white; border-radius: 6px; font-size: 12px; font-weight: 600; }
+        .badge-success { background: var(--green); }
+        .badge-warning { background: var(--orange); }
+        .btn-delete { background: none; border: none; color: var(--red); font-size: 20px; cursor: pointer; padding: 4px 8px; border-radius: 6px; }
+        .empty-state { text-align: center; padding: 40px 20px; color: var(--text-secondary); }
+        .empty-icon { font-size: 48px; margin-bottom: 12px; }
+        .spinner { width: 16px; height: 16px; border: 2px solid var(--bg-tertiary); border-top: 2px solid var(--blue); border-radius: 50%; animation: spin 0.8s linear infinite; display: inline-block; vertical-align: middle; }
+        @keyframes spin { to { transform: rotate(360deg); } }
+        .list-item { padding: 12px 16px; border-bottom: 0.5px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
+        .list-item:last-child { border-bottom: none; }
+    </style>
+</head>
+<body>
+    <div class="header">
+        <h1>OPC UA Control</h1>
+        <div class="status-badge">
+            <div class="status-dot" id="statusDot"></div>
+            <span id="statusText">Disconnected</span>
+        </div>
+    </div>
+
+    <div class="toolbar">
+        <button class="btn btn-success" onclick="loadRoot()" id="loadTreeBtn">🌳 Load Tree</button>
+        <button class="btn" onclick="exportTwin()">⬇ Export JSON</button>
+        <button class="btn" onclick="toggleAutoRefresh()"><span id="refreshLabel">▶ Live</span></button>
+        <span class="twin-status" id="twinStatus"></span>
+    </div>
+
+    <div class="container">
+        <div class="grid">
+            <!-- Tree -->
+            <div class="card">
+                <div class="card-header">
+                    <div class="card-title">OPC UA Tree</div>
+                    <div id="treeInfo" style="font-size:12px;color:var(--text-secondary)"></div>
+                </div>
+                <div class="tree-container">
+                    <div id="treeView">
+                        <div class="empty-state">
+                            <div class="empty-icon">🌳</div>
+                            <div>Click "Load Tree"</div>
+                        </div>
+                    </div>
+                </div>
+            </div>
+
+            <!-- Right column -->
+            <div>
+                <div class="card">
+                    <div class="card-header">
+                        <div class="card-title">Monitored Nodes</div>
+                        <span class="badge" id="nodeCount">0</span>
+                    </div>
+                    <div class="table-container">
+                        <table>
+                            <thead>
+                                <tr>
+                                    <th>Name</th>
+                                    <th>NodeID</th>
+                                    <th>NS</th>
+                                    <th>Type</th>
+                                    <th>Value</th>
+                                    <th>Actions</th>
+                                    <th></th>
+                                </tr>
+                            </thead>
+                            <tbody id="nodesTableBody">
+                                <tr><td colspan="7"><div class="empty-state"><div class="empty-icon">📊</div><div>No nodes</div></div></td></tr>
+                            </tbody>
+                        </table>
+                    </div>
+                </div>
+
+                <div class="card">
+                    <div class="card-header">
+                        <div class="card-title">Actions</div>
+                        <span class="badge badge-success" id="actionCount">0</span>
+                    </div>
+                    <div id="actionsList">
+                        <div class="empty-state"><div class="empty-icon">⚡</div><div>No actions</div></div>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+
+    <!-- Action Modal -->
+    <div class="modal" id="actionModal">
+        <div class="modal-content">
+            <div class="modal-header">Create Action</div>
+            <div class="form-group">
+                <label class="form-label">Name</label>
+                <input type="text" class="form-input" id="actionName" placeholder="Temperature Alert">
+            </div>
+            <div class="form-group">
+                <label class="form-label">Trigger Type</label>
+                <select class="form-select" id="triggerType" onchange="updateTriggerFields()">
+                    <option value="ON_CHANGE">On Change</option>
+                    <option value="ON_EVEN">On Even Number</option>
+                    <option value="ON_ODD">On Odd Number</option>
+                    <option value="ON_TRUE">On True</option>
+                    <option value="ON_FALSE">On False</option>
+                    <option value="ON_VALUE">On Specific Value</option>
+                    <option value="ON_GREATER_THAN">On Greater Than</option>
+                    <option value="ON_LESS_THAN">On Less Than</option>
+                    <option value="ON_INTERVAL">On Time Interval</option>
+                </select>
+            </div>
+            <div class="form-group" id="triggerValueGroup" style="display:none">
+                <label class="form-label">Trigger Value</label>
+                <input type="text" class="form-input" id="triggerValue" placeholder="e.g., 100">
+            </div>
+            <div class="form-group" id="intervalGroup" style="display:none">
+                <label class="form-label">Interval (ms)</label>
+                <input type="number" class="form-input" id="intervalMs" value="1000">
+            </div>
+            <div class="form-group">
+                <label class="form-label" style="display:flex;gap:8px;align-items:center">
+                    <input type="checkbox" id="conditionEnabled" onchange="toggleConditionConfig()">
+                    Bedingung über markierte NodeIDs aktivieren
+                </label>
+                <div id="conditionConfig" style="display:none;margin-top:10px">
+                    <label class="form-label">NodeIDs als Script-Variablen übernehmen</label>
+                    <div id="conditionNodeList" style="max-height:140px;overflow:auto;border:1px solid var(--border);border-radius:8px;padding:8px;background:#fff"></div>
+                    <label class="form-label" style="margin-top:10px">Condition JavaScript (muss true/false zurückgeben)</label>
+                    <textarea class="form-textarea" id="conditionScript" placeholder="Number(values.Temperature) > 70 && Humidity < 65"></textarea>
+                </div>
+            </div>
+            <div class="form-group">
+                <label class="form-label">JavaScript Code</label>
+                <textarea class="form-textarea" id="scriptCode" placeholder="function warn(msg){ console.log(msg); }&#10;warn('Value: ' + currentValue);&#10;opc.write(nodes.OutputNode, true);"></textarea>
+            </div>
+            <div style="display:flex;gap:8px">
+                <button class="btn" style="flex:1" onclick="saveAction()">Save</button>
+                <button class="btn btn-secondary" style="flex:1" onclick="closeModal()">Cancel</button>
+            </div>
+        </div>
+    </div>
+
+    <!-- Edit Value Modal -->
+    <div class="modal" id="editValueModal">
+        <div class="modal-content">
+            <div class="modal-header">Edit Value</div>
+            <div class="form-group">
+                <label class="form-label">Node ID</label>
+                <input type="text" class="form-input" id="editNodeId" readonly>
+            </div>
+            <div class="form-group">
+                <label class="form-label">New Value</label>
+                <input type="text" class="form-input" id="editValue">
+            </div>
+            <div style="display:flex;gap:8px">
+                <button class="btn btn-success" style="flex:1" onclick="writeValue()">Write</button>
+                <button class="btn btn-secondary" style="flex:1" onclick="closeEditValueModal()">Cancel</button>
+            </div>
+        </div>
+    </div>
+
+    <script>
+        const API = window.location.origin + '/api';
+        let nodes = [], actions = [], isConnected = false, currentNodeForAction = null, autoRefreshInterval = null;
+
+        // ── Status polling ────────────────────────────────────────────────────
+        setInterval(checkStatus, 5000);
+        checkStatus();
+        setInterval(pollTwinStatus, 4000);
+        loadActions();
+
+        async function checkStatus() {
+            try {
+                const d = await (await fetch(API + '/status')).json();
+                isConnected = d.connected;
+                document.getElementById('statusDot').classList.toggle('connected', isConnected);
+                document.getElementById('statusText').textContent = isConnected ? 'Connected' : 'Disconnected';
+            } catch(e) { isConnected = false; }
+        }
+
+        async function pollTwinStatus() {
+            try {
+                const d = await (await fetch(API + '/twin-status')).json();
+                const el = document.getElementById('twinStatus');
+                if (d.ready) {
+                    el.textContent = '✅ Export bereit (' + d.nodeCount + ' Nodes)';
+                } else if (d.building) {
+                    el.textContent = '⏳ Export wird gebaut…';
+                } else {
+                    el.textContent = '';
+                }
+            } catch(e) {}
+        }
+
+        // ── Tree: lazy browse ─────────────────────────────────────────────────
+        async function loadRoot() {
+            if (!isConnected) { alert('Not connected'); return; }
+            const btn = document.getElementById('loadTreeBtn');
+            btn.disabled = true;
+            const container = document.getElementById('treeView');
+            container.innerHTML = '<div style="padding:20px;text-align:center"><span class="spinner"></span> Loading…</div>';
+
+            try {
+                const d = await browseNode(null);
+                container.innerHTML = '';
+                container.appendChild(buildUl(d.children));
+                document.getElementById('treeInfo').textContent = d.children.length + ' root nodes';
+            } catch(e) {
+                container.innerHTML = '<div class="empty-state"><div>Error: ' + e.message + '</div></div>';
+            } finally {
+                btn.disabled = false;
+            }
+        }
+
+        async function browseNode(nodeId) {
+            const r = await fetch(API + '/browse-tree', {
+                method: 'POST',
+                headers: {'Content-Type': 'application/json'},
+                body: JSON.stringify(nodeId ? {nodeId} : {})
+            });
+            const d = await r.json();
+            if (!d.success) throw new Error(d.error || 'Browse failed');
+            return d;
+        }
+
+        function buildUl(children) {
+            const ul = document.createElement('div');
+            for (const n of children) {
+                const wrap = document.createElement('div');
+
+                const row = document.createElement('div');
+                row.className = 'tree-node';
+
+                const content = document.createElement('div');
+                content.className = 'tree-node-content';
+
+                // Expand button
+                const expand = document.createElement('div');
+                expand.className = 'tree-expand';
+                expand.textContent = '›';
+                expand.onclick = async (e) => {
+                    e.stopPropagation();
+                    const childContainer = wrap.querySelector('.tree-children');
+                    if (childContainer.classList.contains('show')) {
+                        childContainer.classList.remove('show');
+                        expand.classList.remove('expanded');
+                        return;
+                    }
+                    // Lazy load children
+                    if (childContainer.children.length === 0) {
+                        expand.classList.add('loading-spin');
+                        expand.textContent = '○';
+                        try {
+                            const d = await browseNode(n.nodeId);
+                            if (d.children.length > 0) {
+                                childContainer.appendChild(buildUl(d.children));
+                            } else {
+                                childContainer.innerHTML = '<div style="padding:8px 16px;font-size:12px;color:var(--text-secondary)">No children</div>';
+                            }
+                        } catch(err) {
+                            childContainer.innerHTML = '<div style="padding:8px;color:var(--red)">Error loading</div>';
+                        }
+                        expand.classList.remove('loading-spin');
+                        expand.textContent = '›';
+                    }
+                    childContainer.classList.add('show');
+                    expand.classList.add('expanded');
+                };
+
+                const isVar = n.nodeClass === 'Variable';
+                const icon = isVar ? '📊' : (n.nodeClass === 'View' ? '👁' : '📁');
+
+                const label = document.createElement('span');
+                label.style.flex = '1';
+                label.innerHTML = `<span style="margin-right:6px">${icon}</span><b>${esc(n.displayName || n.browseName)}</b><span style="font-size:11px;color:var(--text-secondary);margin-left:6px">${n.nodeClass || ''}</span>`;
+
+                // Value badge for Variables
+                if (isVar && n.value != null) {
+                    const badge = document.createElement('span');
+                    badge.className = 'value-badge';
+                    badge.textContent = n.value;
+                    label.appendChild(badge);
+                }
+
+                // Click to add to monitoring
+                label.onclick = () => addNode(n.nodeId, n.displayName || n.browseName);
+                label.style.cursor = 'pointer';
+
+                content.appendChild(expand);
+                content.appendChild(label);
+                row.appendChild(content);
+
+                const childContainer = document.createElement('div');
+                childContainer.className = 'tree-children';
+
+                wrap.appendChild(row);
+                wrap.appendChild(childContainer);
+                ul.appendChild(wrap);
+            }
+            return ul;
+        }
+
+        // ── Monitoring table ──────────────────────────────────────────────────
+        function addNode(nodeId, name) {
+            if (nodes.find(n => n.id === nodeId)) { alert('Already added'); return; }
+            const m = nodeId.match(/ns=(\d+);([a-z])=/i);
+            nodes.push({
+                id: nodeId, name,
+                ns:   m ? m[1] : '?',
+                type: m ? (m[2].toLowerCase() === 's' ? 'String' : 'UInteger') : '?',
+                value: '…'
+            });
+            renderTable();
+            readValue(nodeId);
+        }
+
+        async function readValue(nodeId) {
+            try {
+                const d = await (await fetch(API + '/read', {
+                    method: 'POST',
+                    headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId})
+                })).json();
+                if (d.success) {
+                    const n = nodes.find(x => x.id === nodeId);
+                    if (n) {
+                        const cell = document.querySelector(`[data-node-id="${nodeId}"] .value-cell`);
+                        if (cell && n.value !== d.value) {
+                            cell.classList.add('updating');
+                            setTimeout(() => cell.classList.remove('updating'), 500);
+                        }
+                        n.value = d.value;
+                        renderTable();
+                    }
+                }
+            } catch(e) {}
+        }
+
+        function renderTable() {
+            const tb = document.getElementById('nodesTableBody');
+            document.getElementById('nodeCount').textContent = nodes.length;
+            if (nodes.length === 0) {
+                tb.innerHTML = '<tr><td colspan="7"><div class="empty-state"><div class="empty-icon">📊</div><div>No nodes — click a tree node to add</div></div></td></tr>';
+                return;
+            }
+            tb.innerHTML = nodes.map((n, i) => `
+                <tr data-node-id="${esc(n.id)}">
+                    <td style="font-weight:600">${esc(n.name)}</td>
+                    <td style="font-size:12px;color:var(--text-secondary)">${esc(n.id)}</td>
+                    <td><span class="badge">${n.ns}</span></td>
+                    <td><span class="badge badge-warning">${n.type}</span></td>
+                    <td><span class="value-cell" onclick="editVal('${esc(n.id)}','${esc(n.value)}')">${esc(n.value)}</span></td>
+                    <td><button class="btn btn-small" onclick="openActions('${esc(n.id)}')">Actions</button></td>
+                    <td><button class="btn-delete" onclick="removeNode(${i})">×</button></td>
+                </tr>`).join('');
+        }
+
+        function removeNode(idx) {
+            if (confirm('Remove ' + nodes[idx].name + '?')) { nodes.splice(idx, 1); renderTable(); }
+        }
+
+        function toggleAutoRefresh() {
+            if (autoRefreshInterval) {
+                clearInterval(autoRefreshInterval);
+                autoRefreshInterval = null;
+                document.getElementById('refreshLabel').textContent = '▶ Live';
+            } else {
+                autoRefreshInterval = setInterval(() => nodes.forEach(n => readValue(n.id)), 2000);
+                document.getElementById('refreshLabel').textContent = '⏹ Stop';
+                nodes.forEach(n => readValue(n.id));
+            }
+        }
+
+        // ── Export ────────────────────────────────────────────────────────────
+        function exportTwin() {
+            window.open(API + '/export', '_blank');
+        }
+
+        // ── Write value ───────────────────────────────────────────────────────
+        function editVal(nodeId, val) {
+            document.getElementById('editNodeId').value = nodeId;
+            document.getElementById('editValue').value = val;
+            document.getElementById('editValueModal').classList.add('active');
+        }
+        function closeEditValueModal() { document.getElementById('editValueModal').classList.remove('active'); }
+
+        async function writeValue() {
+            const nodeId = document.getElementById('editNodeId').value;
+            const value  = document.getElementById('editValue').value;
+            try {
+                const d = await (await fetch(API + '/write', {
+                    method: 'POST',
+                    headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId, value})
+                })).json();
+                if (d.success) {
+                    const n = nodes.find(x => x.id === nodeId);
+                    if (n) { n.value = value; renderTable(); }
+                    closeEditValueModal();
+                } else alert('Write failed');
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        // ── Actions ───────────────────────────────────────────────────────────
+        function openActions(nodeId) {
+            currentNodeForAction = nodeId;
+            renderConditionNodeList();
+            document.getElementById('actionModal').classList.add('active');
+        }
+        function closeModal() { document.getElementById('actionModal').classList.remove('active'); }
+
+        function updateTriggerFields() {
+            const t = document.getElementById('triggerType').value;
+            document.getElementById('triggerValueGroup').style.display =
+                ['ON_VALUE','ON_GREATER_THAN','ON_LESS_THAN'].includes(t) ? 'block' : 'none';
+            document.getElementById('intervalGroup').style.display =
+                t === 'ON_INTERVAL' ? 'block' : 'none';
+        }
+
+        function toggleConditionConfig() {
+            document.getElementById('conditionConfig').style.display =
+                document.getElementById('conditionEnabled').checked ? 'block' : 'none';
+        }
+
+        function renderConditionNodeList() {
+            const box = document.getElementById('conditionNodeList');
+            if (!nodes.length) {
+                box.innerHTML = '<div style="font-size:12px;color:var(--text-secondary)">Keine überwachten Nodes vorhanden.</div>';
+                return;
+            }
+            box.innerHTML = nodes.map(n => {
+                const checked = n.id === currentNodeForAction ? 'checked' : '';
+                const alias = safeAlias(n.name || n.id);
+                return `<label style="display:flex;gap:8px;align-items:center;padding:4px 0">
+                    <input type="checkbox" class="cond-node" value="${esc(n.id)}" data-alias="${esc(alias)}" ${checked}>
+                    <span><b>${esc(alias)}</b> = <span style="font-size:11px;color:var(--text-secondary)">${esc(n.id)}</span></span>
+                </label>`;
+            }).join('');
+        }
+
+        function selectedConditionNodes() {
+            const ids = [], aliases = {};
+            document.querySelectorAll('.cond-node:checked').forEach(cb => {
+                ids.push(cb.value);
+                aliases[cb.value] = cb.dataset.alias || safeAlias(cb.value);
+            });
+            return {ids, aliases};
+        }
+
+        async function loadActions() {
+            try {
+                const d = await (await fetch(API + '/actions')).json();
+                if (d.success) {
+                    actions = d.actions || [];
+                    renderActions();
+                }
+            } catch(e) {}
+        }
+
+        async function saveAction() {
+            const selected = selectedConditionNodes();
+            const a = {
+                nodeId:   currentNodeForAction,
+                name:     document.getElementById('actionName').value,
+                trigger:  document.getElementById('triggerType').value,
+                value:    document.getElementById('triggerValue').value,
+                interval: document.getElementById('intervalMs').value,
+                conditionEnabled: document.getElementById('conditionEnabled').checked,
+                conditionScript: document.getElementById('conditionScript').value,
+                conditionNodeIds: selected.ids,
+                nodeAliases: selected.aliases,
+                script:   document.getElementById('scriptCode').value
+            };
+            if (!a.name || !a.script) { alert('Name and Script required!'); return; }
+            try {
+                const d = await (await fetch(API + '/actions', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify(a)
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Save action failed');
+                await loadActions();
+                closeModal();
+                document.getElementById('actionName').value = '';
+                document.getElementById('scriptCode').value = '';
+                document.getElementById('conditionScript').value = '';
+                document.getElementById('conditionEnabled').checked = false;
+                toggleConditionConfig();
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        function renderActions() {
+            const al = document.getElementById('actionsList');
+            document.getElementById('actionCount').textContent = actions.length;
+            if (actions.length === 0) {
+                al.innerHTML = '<div class="empty-state"><div class="empty-icon">⚡</div><div>No actions</div></div>';
+                return;
+            }
+            al.innerHTML = actions.map((a, i) => `
+                <div class="list-item">
+                    <div>
+                        <div style="font-weight:600">${esc(a.actionName || a.name)}</div>
+                        <div style="font-size:12px;color:var(--text-secondary);margin-top:4px">
+                            ${esc(a.triggerType || a.trigger)} · ${esc(a.nodeId || '')}
+                            ${a.conditionEnabled ? ' · condition' : ''}
+                        </div>
+                    </div>
+                    <div style="display:flex;gap:6px">
+                        <button class="btn btn-small" onclick="testAction(${i})">Test</button>
+                        <button class="btn-delete" onclick="deleteAction(${i})">×</button>
+                    </div>
+                </div>`).join('');
+        }
+
+        async function testAction(i) {
+            const a = actions[i];
+            try {
+                const d = await (await fetch(API + '/actions/test', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId: a.nodeId, actionName: a.actionName || a.name, value: 'TEST'})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Test failed');
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        async function deleteAction(i) {
+            const a = actions[i];
+            if (!confirm('Delete: ' + (a.actionName || a.name) + '?')) return;
+            try {
+                const d = await (await fetch(API + '/actions/delete', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId: a.nodeId, actionName: a.actionName || a.name})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Delete failed');
+                await loadActions();
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        function safeAlias(s) {
+            s = (s || 'node').toString().replace(/[^A-Za-z0-9_$]/g, '_');
+            return /^[A-Za-z_$]/.test(s) ? s : 'n_' + s;
+        }
+
+        function esc(s) {
+            if (!s) return '';
+            return s.toString().replace(/[&<>"']/g, m =>
+                ({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;',"'":'&#039;'}[m]));
+        }
+    </script>
+</body>
+</html>
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..fa273f4
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,322 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
+         http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>de.opcua</groupId>
+    <artifactId>opcua-gui</artifactId>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+
+    <properties>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <javafx.version>21</javafx.version>
+        <milo.version>0.6.16</milo.version>
+    </properties>
+
+    <dependencies>
+        <!-- JavaFX -->
+        <dependency>
+            <groupId>org.openjfx</groupId>
+            <artifactId>javafx-controls</artifactId>
+            <version>${javafx.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjfx</groupId>
+            <artifactId>javafx-fxml</artifactId>
+            <version>${javafx.version}</version>
+        </dependency>
+
+        <!-- OPC UA / Eclipse Milo 0.6.x (0.x API: readValue, writeValue, thenApply on connect/disconnect) -->
+        <dependency>
+            <groupId>org.eclipse.milo</groupId>
+            <artifactId>sdk-client</artifactId>
+            <version>${milo.version}</version>
+        </dependency>
+
+        <!-- Jackson for JSON -->
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.15.2</version>
+        </dependency>
+
+        <!-- JavaScript editor in JavaFX dialogs -->
+        <dependency>
+            <groupId>org.fxmisc.richtext</groupId>
+            <artifactId>richtextfx</artifactId>
+            <version>0.11.2</version>
+        </dependency>
+
+        <!-- GraalVM JS -->
+        <dependency>
+            <groupId>org.graalvm.js</groupId>
+            <artifactId>js</artifactId>
+            <version>23.0.1</version>
+        </dependency>
+        <dependency>
+            <groupId>org.graalvm.js</groupId>
+            <artifactId>js-scriptengine</artifactId>
+            <version>23.0.1</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <includes>
+                    <include>**/*</include>
+                </includes>
+            </resource>
+        </resources>
+
+        <plugins>
+            <!-- Step 1: Copy the platform-specific JavaFX JARs into target/javafx-jars/
+                         so they can be embedded whole (not unpacked) into the fat JAR.
+                         We copy all three classifiers so the same JAR works on Linux,
+                         Windows and macOS - the Launcher extracts only those it finds. -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-dependency-plugin</artifactId>
+                <version>3.6.0</version>
+                <executions>
+                    <execution>
+                        <id>copy-javafx-jars</id>
+                        <phase>prepare-package</phase>
+                        <goals>
+                            <goal>copy</goal>
+                        </goals>
+                        <configuration>
+                            <outputDirectory>${project.build.directory}/javafx-jars</outputDirectory>
+                            <stripVersion>false</stripVersion>
+                            <artifactItems>
+                                <!-- Linux -->
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-controls</artifactId>
+                                    <version>${javafx.version}</version><classifier>linux</classifier><type>jar</type>
+                                </artifactItem>
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-fxml</artifactId>
+                                    <version>${javafx.version}</version><classifier>linux</classifier><type>jar</type>
+                                </artifactItem>
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-base</artifactId>
+                                    <version>${javafx.version}</version><classifier>linux</classifier><type>jar</type>
+                                </artifactItem>
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-graphics</artifactId>
+                                    <version>${javafx.version}</version><classifier>linux</classifier><type>jar</type>
+                                </artifactItem>
+                                <!-- Windows -->
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-controls</artifactId>
+                                    <version>${javafx.version}</version><classifier>win</classifier><type>jar</type>
+                                </artifactItem>
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-fxml</artifactId>
+                                    <version>${javafx.version}</version><classifier>win</classifier><type>jar</type>
+                                </artifactItem>
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-base</artifactId>
+                                    <version>${javafx.version}</version><classifier>win</classifier><type>jar</type>
+                                </artifactItem>
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-graphics</artifactId>
+                                    <version>${javafx.version}</version><classifier>win</classifier><type>jar</type>
+                                </artifactItem>
+                                <!-- macOS -->
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-controls</artifactId>
+                                    <version>${javafx.version}</version><classifier>mac</classifier><type>jar</type>
+                                </artifactItem>
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-fxml</artifactId>
+                                    <version>${javafx.version}</version><classifier>mac</classifier><type>jar</type>
+                                </artifactItem>
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-base</artifactId>
+                                    <version>${javafx.version}</version><classifier>mac</classifier><type>jar</type>
+                                </artifactItem>
+                                <artifactItem>
+                                    <groupId>org.openjfx</groupId><artifactId>javafx-graphics</artifactId>
+                                    <version>${javafx.version}</version><classifier>mac</classifier><type>jar</type>
+                                </artifactItem>
+                            </artifactItems>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <!-- Step 2: Include the staged JavaFX JARs as META-INF/javafx/*.jar
+                         inside the fat JAR.  The Shade plugin then picks them up
+                         as opaque resources (not unpacked), because they are in
+                         src/main/resources-equivalent path at package time. -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-resources-plugin</artifactId>
+                <version>3.3.1</version>
+                <executions>
+                    <execution>
+                        <id>copy-javafx-into-resources</id>
+                        <phase>prepare-package</phase>
+                        <goals>
+                            <goal>copy-resources</goal>
+                        </goals>
+                        <configuration>
+                            <outputDirectory>${project.build.outputDirectory}/META-INF/javafx</outputDirectory>
+                            <resources>
+                                <resource>
+                                    <directory>${project.build.directory}/javafx-jars</directory>
+                                    <filtering>false</filtering>
+                                </resource>
+                            </resources>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <source>17</source>
+                    <target>17</target>
+                </configuration>
+            </plugin>
+
+            <!-- JavaFX Maven Plugin (nur fuer mvn javafx:run in der Entwicklung) -->
+            <plugin>
+                <groupId>org.openjfx</groupId>
+                <artifactId>javafx-maven-plugin</artifactId>
+                <version>0.0.8</version>
+                <configuration>
+                    <mainClass>de.opcua.app.MainApp</mainClass>
+                </configuration>
+            </plugin>
+
+            <!-- maven-jar-plugin: Main-Class im nicht-shaded JAR setzen -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.3.0</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <mainClass>de.opcua.app.Launcher</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
+
+            <!-- Maven Shade Plugin for Fat JAR -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>3.5.0</version>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <createDependencyReducedPom>false</createDependencyReducedPom>
+                            <shadedArtifactAttached>false</shadedArtifactAttached>
+                            <transformers>
+                                <!-- Main Manifest -->
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <mainClass>de.opcua.app.Launcher</mainClass>
+                                </transformer>
+                                <!-- Service Files -->
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
+                                <!-- NOTICE/LICENSE-Dateien zusammenführen -->
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.ApacheLicenseResourceTransformer"/>
+                            </transformers>
+                            <filters>
+                                <filter>
+                                    <artifact>*:*</artifact>
+                                    <excludes>
+                                        <exclude>META-INF/*.SF</exclude>
+                                        <exclude>META-INF/*.DSA</exclude>
+                                        <exclude>META-INF/*.RSA</exclude>
+                                        <exclude>META-INF/versions/*/module-info.class</exclude>
+                                    </excludes>
+                                </filter>
+                                <!--
+                                    JavaFX .class-Dateien NICHT in die Shade-Klassen entpacken.
+                                    Die JavaFX-JARs liegen als ganze Dateien unter
+                                    META-INF/javafx/*.jar im Fat-JAR und werden vom Launcher
+                                    zur Laufzeit als Modul-Pfad extrahiert.
+                                -->
+                                <filter>
+                                    <artifact>org.openjfx:*</artifact>
+                                    <excludes>
+                                        <exclude>**/*.class</exclude>
+                                        <exclude>META-INF/native-image/**</exclude>
+                                    </excludes>
+                                </filter>
+                            </filters>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <profiles>
+        <profile>
+            <id>windows-exe</id>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>com.akathist.maven.plugins.launch4j</groupId>
+                        <artifactId>launch4j-maven-plugin</artifactId>
+                        <version>2.7.0</version>
+                        <executions>
+                            <execution>
+                                <id>build-windows-exe</id>
+                                <phase>package</phase>
+                                <goals>
+                                    <goal>launch4j</goal>
+                                </goals>
+                                <configuration>
+                                    <headerType>gui</headerType>
+                                    <outfile>${project.build.directory}/opcua-gui.exe</outfile>
+                                    <jar>${project.build.directory}/${project.build.finalName}.jar</jar>
+                                    <dontWrapJar>false</dontWrapJar>
+                                    <icon>src/main/resources/styles/opcua-client.ico</icon>
+                                    <errTitle>OPC UA Client</errTitle>
+                                    <classPath>
+                                        <mainClass>de.opcua.app.Launcher</mainClass>
+                                    </classPath>
+                                    <jre>
+                                        <minVersion>17</minVersion>
+                                    </jre>
+                                    <versionInfo>
+                                        <fileVersion>1.0.0.0</fileVersion>
+                                        <txtFileVersion>${project.version}</txtFileVersion>
+                                        <fileDescription>OPC UA Client</fileDescription>
+                                        <copyright>OPC UA Client</copyright>
+                                        <productVersion>1.0.0.0</productVersion>
+                                        <txtProductVersion>${project.version}</txtProductVersion>
+                                        <productName>OPC UA Client</productName>
+                                        <internalName>opcua-gui</internalName>
+                                        <originalFilename>opcua-gui.exe</originalFilename>
+                                    </versionInfo>
+                                </configuration>
+                            </execution>
+                        </executions>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
+
+</project>
diff --git a/settings.json b/settings.json
new file mode 100644
index 0000000..a13284c
--- /dev/null
+++ b/settings.json
@@ -0,0 +1,14 @@
+{
+  "scriptLogLevel" : "INFO",
+  "Endpoint" : "opc.tcp://opcua.123mc.com:4840",
+  "httpEnabled" : true,
+  "keystorePassword" : "",
+  "httpsEnabled" : false,
+  "httpPort" : 8081,
+  "keystoreType" : "JKS",
+  "scriptLoggingEnabled" : true,
+  "Host" : "http://localhost:8080",
+  "httpsPort" : 8443,
+  "scriptLogDirectory" : "/home/chris/.opcua-gui/logs",
+  "keystorePath" : ""
+}
\ No newline at end of file
diff --git a/src/main/java/de/opcua/app/Launcher.java b/src/main/java/de/opcua/app/Launcher.java
new file mode 100644
index 0000000..867a388
--- /dev/null
+++ b/src/main/java/de/opcua/app/Launcher.java
@@ -0,0 +1,150 @@
+package de.opcua.app;
+
+import java.io.*;
+import java.lang.management.ManagementFactory;
+import java.net.URISyntaxException;
+import java.nio.file.*;
+import java.util.*;
+import java.util.zip.*;
+
+/**
+ * Bootstrap entry point for the fat JAR.
+ *
+ * Extracts only the platform-specific JavaFX JARs that match the
+ * current OS (linux / win / mac) from META-INF/javafx/ inside this
+ * fat JAR into a temp directory, then re-executes itself with
+ * --module-path pointing at that directory.
+ *
+ * This avoids the "Two versions of module javafx.base found" error
+ * that occurs when all three platform JARs end up in the same folder.
+ */
+public class Launcher {
+
+    private static final String RELAUNCHED_PROP   = "opcua.relaunched";
+    private static final String JAVAFX_RESOURCE_DIR = "META-INF/javafx/";
+
+    public static void main(String[] args) throws Exception {
+
+        // Already in child process → delegate directly.
+        if (System.getProperty(RELAUNCHED_PROP) != null) {
+            MainApp.main(args);
+            return;
+        }
+
+        // Service mode: no JavaFX needed.
+        if (isServiceMode(args)) {
+            relaunch(args, null);
+            return;
+        }
+
+        // UI mode: extract platform JARs, then relaunch with module-path.
+        Path javafxDir = extractJavafxJars();
+        if (javafxDir == null) {
+            // Running from IDE / exploded classes — JavaFX already on path.
+            MainApp.main(args);
+            return;
+        }
+        relaunch(args, javafxDir);
+    }
+
+    // ── helpers ───────────────────────────────────────────────────────────
+
+    private static boolean isServiceMode(String[] args) {
+        for (String a : args)
+            if ("--service".equalsIgnoreCase(a) || "service".equalsIgnoreCase(a)) return true;
+        return false;
+    }
+
+    /**
+     * Detects the current OS and returns the JavaFX classifier string:
+     * "linux", "win", or "mac".
+     */
+    private static String platformClassifier() {
+        String os = System.getProperty("os.name", "").toLowerCase(java.util.Locale.ROOT);
+        if (os.contains("win"))   return "win";
+        if (os.contains("mac"))   return "mac";
+        return "linux";
+    }
+
+    /**
+     * Extracts JARs from META-INF/javafx/ inside the running fat JAR
+     * whose file name contains the current platform classifier.
+     * Returns the temp directory, or null if no embedded JARs exist.
+     */
+    private static Path extractJavafxJars() throws IOException, URISyntaxException {
+        File selfJar;
+        try {
+            selfJar = new File(
+                Launcher.class.getProtectionDomain().getCodeSource().getLocation().toURI());
+        } catch (Exception e) {
+            return null;
+        }
+        if (!selfJar.isFile()) return null;
+
+        String classifier = platformClassifier();
+        Path tmpDir = Files.createTempDirectory("opcua-javafx-");
+        tmpDir.toFile().deleteOnExit();
+
+        boolean found = false;
+        try (ZipFile zip = new ZipFile(selfJar)) {
+            Enumeration<? extends ZipEntry> entries = zip.entries();
+            while (entries.hasMoreElements()) {
+                ZipEntry entry = entries.nextElement();
+                String name = entry.getName();
+                if (!name.startsWith(JAVAFX_RESOURCE_DIR) || entry.isDirectory()) continue;
+
+                String fileName = name.substring(JAVAFX_RESOURCE_DIR.length());
+                if (fileName.isEmpty() || !fileName.endsWith(".jar")) continue;
+
+                // Only extract JARs for the current platform.
+                if (!fileName.contains(classifier)) continue;
+
+                Path dest = tmpDir.resolve(fileName);
+                try (InputStream in = zip.getInputStream(entry)) {
+                    Files.copy(in, dest, StandardCopyOption.REPLACE_EXISTING);
+                }
+                found = true;
+            }
+        }
+        return found ? tmpDir : null;
+    }
+
+    /**
+     * Re-executes this process as a child with optional --module-path flags.
+     */
+    private static void relaunch(String[] appArgs, Path javafxDir) throws Exception {
+        String javaExe = ProcessHandle.current().info().command()
+                .orElse(System.getProperty("java.home")
+                        + File.separator + "bin" + File.separator + "java");
+
+        File selfJar = new File(
+            Launcher.class.getProtectionDomain().getCodeSource().getLocation().toURI());
+
+        List<String> cmd = new ArrayList<>();
+        cmd.add(javaExe);
+
+        for (String jvmArg : ManagementFactory.getRuntimeMXBean().getInputArguments()) {
+            if (jvmArg.startsWith("-javaagent")
+                    || jvmArg.startsWith("--module-path")
+                    || jvmArg.startsWith("--add-modules")) continue;
+            cmd.add(jvmArg);
+        }
+
+        cmd.add("-D" + RELAUNCHED_PROP + "=true");
+
+        if (javafxDir != null) {
+            cmd.add("--module-path");
+            cmd.add(javafxDir.toAbsolutePath().toString());
+            cmd.add("--add-modules");
+            cmd.add("javafx.controls,javafx.fxml");
+        }
+
+        cmd.add("-jar");
+        cmd.add(selfJar.getAbsolutePath());
+        Collections.addAll(cmd, appArgs);
+
+        ProcessBuilder pb = new ProcessBuilder(cmd);
+        pb.inheritIO();
+        System.exit(pb.start().waitFor());
+    }
+}
diff --git a/src/main/java/de/opcua/app/MainApp.java b/src/main/java/de/opcua/app/MainApp.java
new file mode 100644
index 0000000..b6611d3
--- /dev/null
+++ b/src/main/java/de/opcua/app/MainApp.java
@@ -0,0 +1,54 @@
+package de.opcua.app;
+
+import de.opcua.app.service.AppMode;
+
+/**
+ * Entry point — intentionally has NO javafx.* imports.
+ *
+ * The JVM resolves all imports of a class before main() runs.
+ * If this class imported javafx.application.Application directly,
+ * starting with --service (or on a machine without JavaFX on the
+ * classpath) would throw NoClassDefFoundError before a single line
+ * of our code executes.
+ *
+ * UI launch is therefore delegated via reflection so that the JavaFX
+ * classes are only touched when the UI mode is actually requested.
+ */
+public class MainApp {
+    public static void main(String[] args) {
+        AppMode mode = AppMode.fromArgs(args);
+        if (mode == AppMode.SERVICE) {
+            ServiceMain.run(args);
+            return;
+        }
+        launchUi(args);
+    }
+
+    private static void launchUi(String[] args) {
+        try {
+            // Reflect into javafx.application.Application.launch() so that
+            // this class has zero compile-time or load-time dependency on JavaFX.
+            Class<?> applicationClass = Class.forName("javafx.application.Application");
+            Class<?> uiAppClass       = Class.forName("de.opcua.app.UiApp");
+            applicationClass
+                .getMethod("launch", Class.class, String[].class)
+                .invoke(null, uiAppClass, args);
+        } catch (ClassNotFoundException e) {
+            System.err.println(
+                "ERROR: JavaFX runtime not found on the classpath.\n" +
+                "To run the UI, either:\n" +
+                "  a) Install a JDK that bundles JavaFX (e.g. Liberica, Zulu FX), or\n" +
+                "  b) Add the JavaFX SDK to the module path:\n" +
+                "       java --module-path /path/to/javafx-sdk/lib \\\n" +
+                "            --add-modules javafx.controls,javafx.fxml \\\n" +
+                "            -jar target/opcua-gui-1.0.0.jar\n" +
+                "  c) Use Maven during development:  mvn javafx:run"
+            );
+            System.exit(1);
+        } catch (Exception e) {
+            System.err.println("Failed to launch UI: " + e.getMessage());
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+}
diff --git a/src/main/java/de/opcua/app/RestApiLauncher.java b/src/main/java/de/opcua/app/RestApiLauncher.java
new file mode 100644
index 0000000..9cf50e1
--- /dev/null
+++ b/src/main/java/de/opcua/app/RestApiLauncher.java
@@ -0,0 +1,85 @@
+package de.opcua.app;
+
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.rest.OpcUaRestApi;
+import de.opcua.app.scripting.Store;
+import de.opcua.app.service.ActionService;
+
+/**
+ * Standalone REST API launcher for debugging
+ * Run with: mvn exec:java -Dexec.mainClass="de.opcua.app.RestApiLauncher"
+ */
+public class RestApiLauncher {
+    
+    public static void main(String[] args) {
+        System.out.println("═══════════════════════════════════════════");
+        System.out.println("  REST API Standalone Launcher");
+        System.out.println("═══════════════════════════════════════════");
+        System.out.println();
+        
+        try {
+            System.out.println("[1/3] Creating OPC UA Service...");
+            OpcUaService opc = new OpcUaService();
+            System.out.println("✅ OPC UA Service created");
+            
+            System.out.println();
+            Settings settings = new SettingsService().load();
+            System.out.println("[2/3] Creating REST API on port " + settings.httpPort() + "...");
+            ActionService actionService = new ActionService(opc, new Store());
+            OpcUaRestApi api = new OpcUaRestApi(opc, settings.httpPort(), actionService);
+            System.out.println("✅ REST API object created");
+            
+            System.out.println();
+            System.out.println("[3/3] Starting HTTP Server...");
+            api.start();
+            System.out.println("✅ HTTP Server started successfully!");
+            
+            System.out.println();
+            System.out.println("═══════════════════════════════════════════");
+            System.out.println("  ✅ REST API is now running!");
+            System.out.println("═══════════════════════════════════════════");
+            System.out.println();
+            System.out.println("Test with:");
+            System.out.println("  curl http://localhost:" + settings.httpPort() + "/");
+            System.out.println("  curl http://localhost:" + settings.httpPort() + "/api/status");
+            System.out.println();
+            System.out.println("Or open in browser:");
+            System.out.println("  http://localhost:" + settings.httpPort() + "/");
+            System.out.println();
+            System.out.println("Press Ctrl+C to stop...");
+            System.out.println("─────────────────────────────────────────");
+            
+            // Keep alive
+            Thread.sleep(Long.MAX_VALUE);
+            
+        } catch (Exception e) {
+            System.err.println();
+            System.err.println("═══════════════════════════════════════════");
+            System.err.println("  ❌ ERROR - Failed to start REST API!");
+            System.err.println("═══════════════════════════════════════════");
+            System.err.println();
+            System.err.println("Error message: " + e.getMessage());
+            System.err.println();
+            System.err.println("Stack trace:");
+            e.printStackTrace();
+            System.err.println();
+            System.err.println("Common causes:");
+            System.err.println("1. Port 8081 already in use");
+            System.err.println("   Check: lsof -i :8081");
+            System.err.println("   Or:    netstat -an | grep 8081");
+            System.err.println();
+            System.err.println("2. com.sun.net.httpserver not available");
+            System.err.println("   Make sure you're using JDK (not JRE)");
+            System.err.println("   Check: java -version");
+            System.err.println();
+            System.err.println("3. Firewall blocking port");
+            System.err.println("   Try: sudo ufw allow 8081 (Linux)");
+            System.err.println("   Or check System Preferences (macOS)");
+            System.err.println();
+            
+            System.exit(1);
+        }
+    }
+}
diff --git a/src/main/java/de/opcua/app/ServiceMain.java b/src/main/java/de/opcua/app/ServiceMain.java
new file mode 100644
index 0000000..55ee78b
--- /dev/null
+++ b/src/main/java/de/opcua/app/ServiceMain.java
@@ -0,0 +1,265 @@
+package de.opcua.app;
+
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.model.SystemInitScript;
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.rest.OpcUaRestApi;
+import de.opcua.app.scripting.Store;
+import de.opcua.app.service.ActionService;
+import de.opcua.app.service.ActionPersistenceService;
+import de.opcua.app.service.SystemInitScriptService;
+
+import java.time.Instant;
+import java.util.*;
+import java.util.concurrent.*;
+
+/**
+ * Enhanced Service Mode for Windows/Linux background operation
+ * Runs autonomously without GUI
+ */
+public final class ServiceMain {
+
+    private ServiceMain() {}
+
+    public static void run(String[] args) {
+        System.out.println("═══════════════════════════════════════════════════════════");
+        System.out.println("  OPC UA GUI - Service Mode");
+        System.out.println("  Started: " + Instant.now());
+        System.out.println("═══════════════════════════════════════════════════════════");
+
+        // Load configuration
+        SettingsService settingsService = new SettingsService();
+        Settings settings = settingsService.load();
+
+        System.out.println("[Config] Endpoint: " + settings.endpoint());
+        System.out.println("[Config] Host: " + settings.host());
+
+        // Initialize services
+        OpcUaService opc = new OpcUaService();
+        Store store = new Store();
+        ActionService actionService = new ActionService(opc, store);
+        ActionPersistenceService persistence = new ActionPersistenceService();
+        SystemInitScriptService systemInitScripts = new SystemInitScriptService();
+
+        // Initialize REST API from portable settings
+        OpcUaRestApi restApiTmp = null;
+        if (settings.httpEnabled()) {
+            restApiTmp = new OpcUaRestApi(opc, settings.httpPort(), actionService);
+            try {
+                restApiTmp.start();
+            } catch (Exception e) {
+                System.err.println("[REST API] Failed to start: " + e.getMessage());
+            }
+        } else {
+            System.out.println("[REST API] Disabled by settings");
+        }
+        final OpcUaRestApi restApi = restApiTmp;
+
+        // Load saved actions
+        Map<String, List<NodeAction>> savedActions = persistence.loadActions();
+        if (!savedActions.isEmpty()) {
+            System.out.println("[Actions] Loading " + savedActions.size() + " saved node configurations...");
+            actionService.importActionsFromList(savedActions);
+
+            // Try init scripts immediately at program start. Scripts that need OPC UA
+            // can fail here and will be retried after connect/reconnect.
+            actionService.initializeAllActionsAsync("program-start", false)
+                    .whenComplete((summary, ex) -> {
+                        if (ex != null) {
+                            System.err.println("[Actions] Program-start init failed: " + ex.getMessage());
+                        } else {
+                            System.out.println("[Actions] Program-start init: " + summary);
+                        }
+                    });
+        } else {
+            System.out.println("[Actions] No saved actions found - service will monitor configured nodes");
+        }
+
+        // Global system init script (RegLogin/Session) is stored separately from actions.
+        // It can run before OPC connect if configured; scripts that need OPC UA should
+        // usually use runAfterConnect and will execute after connect/reconnect.
+        runSystemInitIfConfigured(actionService, systemInitScripts, "program-start", false, false);
+
+        // Auto-save every 60 seconds
+        persistence.startAutoSave(actionService, 60);
+
+        // Connect to OPC UA Server
+        System.out.println("[OPC UA] Connecting to " + settings.endpoint() + "...");
+        try {
+            opc.connect(settings.endpoint()).get(30, TimeUnit.SECONDS);
+            System.out.println("[OPC UA] ✅ Connected successfully");
+
+            // Globales RegLogin-/System-Init-Script nach OPC Connect ausführen.
+            runSystemInitIfConfigured(actionService, systemInitScripts, "service-connect", true, true);
+
+            // Action-spezifische Initial-Scripts danach ausführen.
+            Map<String, Object> initSummary = actionService.initializeAllActions("service-connect", true);
+            System.out.println("[Actions] Connect init: " + initSummary);
+
+            // ✅ Digital Twin im Hintergrund bauen – API antwortet sofort
+            if (restApi != null) restApi.triggerDigitalTwinBuild();
+
+        } catch (Exception e) {
+            System.err.println("[OPC UA] ❌ Connection failed: " + e.getMessage());
+            System.err.println("[OPC UA] Service will continue and retry...");
+        }
+
+        // Main service loop
+        ScheduledExecutorService exec = Executors.newScheduledThreadPool(2, r -> {
+            Thread t = new Thread(r, "service-loop");
+            t.setDaemon(false);
+            return t;
+        });
+
+        // Monitor and trigger actions
+        exec.scheduleWithFixedDelay(() -> {
+            try {
+                if (!opc.isConnected()) {
+                    // Attempt reconnect
+                    System.out.println("[OPC UA] Not connected, attempting reconnect...");
+                    try {
+                        opc.connect(settings.endpoint()).get(10, TimeUnit.SECONDS);
+                        System.out.println("[OPC UA] ✅ Reconnected");
+
+                        // Datei erneut laden, damit Änderungen aus der Weboberfläche
+                        // im laufenden Service beim nächsten Reconnect wirksam werden.
+                        runSystemInitIfConfigured(actionService, systemInitScripts, "service-reconnect", true, true);
+
+                        Map<String, Object> initSummary = actionService.initializeAllActions("service-reconnect", true);
+                        System.out.println("[Actions] Reconnect init: " + initSummary);
+
+                        // ✅ Digital Twin nach Reconnect neu bauen
+                        if (restApi != null) restApi.triggerDigitalTwinBuild();
+
+                    } catch (Exception e) {
+                        System.err.println("[OPC UA] Reconnect failed: " + e.getMessage());
+                        return;
+                    }
+                }
+
+                // Process all configured actions
+                Map<String, List<NodeAction>> allActions = actionService.getAllActions();
+                if (allActions.isEmpty()) {
+                    return;
+                }
+
+                for (Map.Entry<String, List<NodeAction>> entry : allActions.entrySet()) {
+                    String nodeId = entry.getKey();
+
+                    try {
+                        // Read current value
+                        String value = opc.readValue(nodeId).get(5, TimeUnit.SECONDS);
+
+                        // Trigger actions based on value
+                        actionService.processValueChange(nodeId, value);
+
+                    } catch (Exception e) {
+                        System.err.println("[Service] Error reading " + nodeId + ": " + e.getMessage());
+                    }
+                }
+
+            } catch (Exception e) {
+                System.err.println("[Service] Loop error: " + e.getMessage());
+            }
+        }, 0, 1, TimeUnit.SECONDS);
+
+        // Heartbeat / Status logging
+        exec.scheduleWithFixedDelay(() -> {
+            try {
+                Map<String, List<NodeAction>> allActions = actionService.getAllActions();
+                int totalActions = allActions.values().stream()
+                        .mapToInt(List::size)
+                        .sum();
+
+                long enabledActions = allActions.values().stream()
+                        .flatMap(List::stream)
+                        .filter(NodeAction::isEnabled)
+                        .count();
+
+                System.out.println(
+                        "[Heartbeat] " + Instant.now() +
+                        " | Connected: " + (opc.isConnected() ? "✅" : "❌") +
+                        " | Nodes: " + allActions.size() +
+                        " | Actions: " + totalActions + " (enabled: " + enabledActions + ")"
+                );
+
+            } catch (Exception e) {
+                System.err.println("[Heartbeat] Error: " + e.getMessage());
+            }
+        }, 10, 30, TimeUnit.SECONDS);
+
+        // Shutdown hook for graceful cleanup
+        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+            System.out.println("\n[Service] Shutdown signal received");
+
+            // Save actions before exit
+            System.out.println("[Service] Saving actions...");
+            persistence.saveActions(actionService.getAllActions());
+
+            // Disconnect OPC UA
+            System.out.println("[Service] Disconnecting from OPC UA...");
+            try {
+                opc.disconnect().get(5, TimeUnit.SECONDS);
+            } catch (Exception e) {
+                System.err.println("[Service] Disconnect error: " + e.getMessage());
+            }
+
+            // Stop REST API
+            if (restApi != null) restApi.stop();
+
+            // Shutdown action service
+            System.out.println("[Service] Shutting down action service...");
+            actionService.shutdown();
+
+            // Shutdown executor
+            System.out.println("[Service] Shutting down executor...");
+            exec.shutdown();
+            try {
+                if (!exec.awaitTermination(10, TimeUnit.SECONDS)) {
+                    exec.shutdownNow();
+                }
+            } catch (InterruptedException e) {
+                exec.shutdownNow();
+            }
+
+            System.out.println("[Service] ✅ Shutdown complete");
+        }));
+
+        System.out.println("\n[Service] Service running - Press Ctrl+C to stop");
+        System.out.println("─────────────────────────────────────────────────────────────\n");
+
+        // Keep process alive
+        try {
+            new CountDownLatch(1).await();
+        } catch (InterruptedException ignored) {
+            Thread.currentThread().interrupt();
+        }
+    }
+
+    private static void runSystemInitIfConfigured(ActionService actionService,
+                                                 SystemInitScriptService scriptService,
+                                                 String reason,
+                                                 boolean afterConnect,
+                                                 boolean resetSession) {
+        try {
+            SystemInitScript config = scriptService.load();
+            boolean shouldRun = config.isEnabled()
+                    && !config.getScript().isBlank()
+                    && (afterConnect ? config.isRunAfterConnect() : config.isRunAtProgramStart());
+
+            if (!shouldRun) {
+                System.out.println("[SystemInit] Skipped " + reason + " (disabled or not configured)");
+                return;
+            }
+
+            Map<String, Object> summary = actionService.executeSystemInitScript(config.getScript(), reason, resetSession);
+            System.out.println("[SystemInit] " + reason + ": " + summary);
+        } catch (Exception e) {
+            System.err.println("[SystemInit] " + reason + " failed: " + e.getMessage());
+        }
+    }
+
+
+}
diff --git a/src/main/java/de/opcua/app/UiApp.java b/src/main/java/de/opcua/app/UiApp.java
new file mode 100644
index 0000000..5dea26d
--- /dev/null
+++ b/src/main/java/de/opcua/app/UiApp.java
@@ -0,0 +1,31 @@
+package de.opcua.app;
+
+import javafx.application.Application;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Parent;
+import javafx.scene.Scene;
+import javafx.scene.image.Image;
+import javafx.stage.Stage;
+
+import java.io.InputStream;
+
+public class UiApp extends Application {
+  @Override
+  public void start(Stage stage) throws Exception {
+    FXMLLoader loader = new FXMLLoader(UiApp.class.getResource("/ui/main.fxml"));
+    Parent root = loader.load();
+    Scene scene = new Scene(root, 1262, 619);
+    stage.setTitle("OPC UA Client");
+    stage.setMinWidth(900);
+    stage.setMinHeight(520);
+
+    try (InputStream icon = UiApp.class.getResourceAsStream("/styles/opcua-client-logo.png")) {
+      if (icon != null) {
+        stage.getIcons().add(new Image(icon));
+      }
+    }
+
+    stage.setScene(scene);
+    stage.show();
+  }
+}
diff --git a/src/main/java/de/opcua/app/config/AppPaths.java b/src/main/java/de/opcua/app/config/AppPaths.java
new file mode 100644
index 0000000..158d650
--- /dev/null
+++ b/src/main/java/de/opcua/app/config/AppPaths.java
@@ -0,0 +1,64 @@
+package de.opcua.app.config;
+
+import java.io.File;
+import java.net.URI;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+/**
+ * Central place for all runtime/config files.
+ *
+ * Files are stored in <application-directory>/config so the complete
+ * application can be copied together with its configuration.
+ *
+ * Override with -Dopcua.config.dir=/path/to/config when required.
+ */
+public final class AppPaths {
+    private AppPaths() {}
+
+    public static Path applicationDirectory() {
+        String override = System.getProperty("opcua.app.dir");
+        if (override != null && !override.isBlank()) return Path.of(override).toAbsolutePath().normalize();
+        try {
+            URI uri = AppPaths.class.getProtectionDomain().getCodeSource().getLocation().toURI();
+            Path location = Path.of(uri).toAbsolutePath().normalize();
+            if (Files.isRegularFile(location)) return location.getParent();
+            // In IDE/Maven class directories, prefer current working directory.
+            String loc = location.toString().replace('\\', '/');
+            if (loc.endsWith("/target/classes") || loc.contains("/target/classes/")) {
+                return Path.of(System.getProperty("user.dir")).toAbsolutePath().normalize();
+            }
+            return Files.isDirectory(location) ? location : location.getParent();
+        } catch (Exception ignored) {
+            return Path.of(System.getProperty("user.dir")).toAbsolutePath().normalize();
+        }
+    }
+
+    public static Path configDirectory() {
+        String override = System.getProperty("opcua.config.dir");
+        Path dir = override != null && !override.isBlank()
+                ? Path.of(override)
+                : applicationDirectory().resolve("config");
+        return dir.toAbsolutePath().normalize();
+    }
+
+    public static Path configFile(String fileName) {
+        return configDirectory().resolve(fileName).toAbsolutePath().normalize();
+    }
+
+    public static Path legacyUserConfigDirectory() {
+        return Path.of(System.getProperty("user.home"), ".opcua-gui").toAbsolutePath().normalize();
+    }
+
+    public static void ensureConfigDirectory() {
+        try {
+            Files.createDirectories(configDirectory());
+        } catch (Exception e) {
+            throw new IllegalStateException("Config-Verzeichnis konnte nicht erstellt werden: " + configDirectory(), e);
+        }
+    }
+
+    public static String describe() {
+        return configDirectory().toString();
+    }
+}
diff --git a/src/main/java/de/opcua/app/config/ConfigSecurity.java b/src/main/java/de/opcua/app/config/ConfigSecurity.java
new file mode 100644
index 0000000..cdbf58b
--- /dev/null
+++ b/src/main/java/de/opcua/app/config/ConfigSecurity.java
@@ -0,0 +1,146 @@
+package de.opcua.app.config;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+
+import javax.crypto.Cipher;
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.GCMParameterSpec;
+import javax.crypto.spec.PBEKeySpec;
+import javax.crypto.spec.SecretKeySpec;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.security.MessageDigest;
+import java.security.SecureRandom;
+import java.util.Base64;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * Optional encryption helper for JSON configuration files.
+ *
+ * Format:
+ * {
+ *   "encrypted": true,
+ *   "algorithm": "AES/GCM/NoPadding",
+ *   "kdf": "PBKDF2WithHmacSHA256",
+ *   "iterations": 120000,
+ *   "salt": "...",
+ *   "iv": "...",
+ *   "data": "..."
+ * }
+ */
+public final class ConfigSecurity {
+    private static final ObjectMapper MAPPER = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);
+    private static final SecureRandom RANDOM = new SecureRandom();
+    private static final int ITERATIONS = 120_000;
+    private static final int KEY_BITS = 256;
+    private static final int GCM_TAG_BITS = 128;
+    private static final Base64.Encoder B64E = Base64.getEncoder();
+    private static final Base64.Decoder B64D = Base64.getDecoder();
+
+    private ConfigSecurity() {}
+
+    public static boolean looksEncrypted(Path file) {
+        try {
+            if (file == null || !Files.exists(file)) return false;
+            String text = Files.readString(file, StandardCharsets.UTF_8).trim();
+            return text.startsWith("{") && text.contains("\"encrypted\"") && text.contains("\"data\"");
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
+    public static String readText(Path file, Settings settings) throws IOException {
+        String text = Files.readString(file, StandardCharsets.UTF_8);
+        if (!looksEncrypted(file)) return text;
+        String password = resolveEncryptionPassword(settings);
+        if (password == null || password.isBlank()) {
+            throw new IOException("Datei ist verschlüsselt, aber kein Config-Passwort ist gesetzt: " + file);
+        }
+        try {
+            @SuppressWarnings("unchecked")
+            Map<String, Object> envelope = MAPPER.readValue(text, Map.class);
+            byte[] salt = B64D.decode(String.valueOf(envelope.get("salt")));
+            byte[] iv = B64D.decode(String.valueOf(envelope.get("iv")));
+            byte[] data = B64D.decode(String.valueOf(envelope.get("data")));
+            int iterations = envelope.get("iterations") instanceof Number n ? n.intValue() : ITERATIONS;
+            SecretKeySpec key = deriveKey(password, salt, iterations);
+            Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
+            cipher.init(Cipher.DECRYPT_MODE, key, new GCMParameterSpec(GCM_TAG_BITS, iv));
+            byte[] plain = cipher.doFinal(data);
+            return new String(plain, StandardCharsets.UTF_8);
+        } catch (Exception e) {
+            throw new IOException("Verschlüsselte Config konnte nicht gelesen werden: " + e.getMessage(), e);
+        }
+    }
+
+    public static void writeText(Path file, String plainText, Settings settings) throws IOException {
+        Files.createDirectories(file.getParent());
+        if (settings != null && settings.configEncryptionEnabled()) {
+            String password = resolveEncryptionPassword(settings);
+            if (password == null || password.isBlank()) {
+                throw new IOException("Config-Verschlüsselung ist aktiv, aber kein Config-Passwort ist gesetzt.");
+            }
+            try {
+                byte[] salt = randomBytes(16);
+                byte[] iv = randomBytes(12);
+                SecretKeySpec key = deriveKey(password, salt, ITERATIONS);
+                Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
+                cipher.init(Cipher.ENCRYPT_MODE, key, new GCMParameterSpec(GCM_TAG_BITS, iv));
+                byte[] encrypted = cipher.doFinal(plainText.getBytes(StandardCharsets.UTF_8));
+
+                Map<String, Object> envelope = new LinkedHashMap<>();
+                envelope.put("encrypted", true);
+                envelope.put("algorithm", "AES/GCM/NoPadding");
+                envelope.put("kdf", "PBKDF2WithHmacSHA256");
+                envelope.put("iterations", ITERATIONS);
+                envelope.put("salt", B64E.encodeToString(salt));
+                envelope.put("iv", B64E.encodeToString(iv));
+                envelope.put("data", B64E.encodeToString(encrypted));
+                Files.writeString(file, MAPPER.writeValueAsString(envelope), StandardCharsets.UTF_8);
+                return;
+            } catch (Exception e) {
+                throw new IOException("Config konnte nicht verschlüsselt geschrieben werden: " + e.getMessage(), e);
+            }
+        }
+        Files.writeString(file, plainText, StandardCharsets.UTF_8);
+    }
+
+    public static String resolveEncryptionPassword(Settings settings) {
+        String prop = System.getProperty("opcua.config.password");
+        if (prop != null && !prop.isBlank()) return prop;
+        String env = System.getenv("OPCUA_CONFIG_PASSWORD");
+        if (env != null && !env.isBlank()) return env;
+        return settings == null ? "" : settings.configEncryptionPassword();
+    }
+
+    public static String sha256(String text) {
+        if (text == null || text.isBlank()) return "";
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            return B64E.encodeToString(digest.digest(text.getBytes(StandardCharsets.UTF_8)));
+        } catch (Exception e) {
+            throw new IllegalStateException(e);
+        }
+    }
+
+    public static boolean matchesPassword(String plain, String hash) {
+        if (hash == null || hash.isBlank()) return false;
+        return MessageDigest.isEqual(sha256(plain).getBytes(StandardCharsets.UTF_8), hash.getBytes(StandardCharsets.UTF_8));
+    }
+
+    private static SecretKeySpec deriveKey(String password, byte[] salt, int iterations) throws Exception {
+        PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), salt, iterations, KEY_BITS);
+        byte[] key = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256").generateSecret(spec).getEncoded();
+        return new SecretKeySpec(key, "AES");
+    }
+
+    private static byte[] randomBytes(int len) {
+        byte[] b = new byte[len];
+        RANDOM.nextBytes(b);
+        return b;
+    }
+}
diff --git a/src/main/java/de/opcua/app/config/Settings.java b/src/main/java/de/opcua/app/config/Settings.java
new file mode 100644
index 0000000..3a03358
--- /dev/null
+++ b/src/main/java/de/opcua/app/config/Settings.java
@@ -0,0 +1,82 @@
+package de.opcua.app.config;
+
+import de.opcua.app.logging.ScriptLogger;
+
+/**
+ * Enhanced Settings with HTTP/HTTPS, portable config, encryption and REST auth.
+ */
+public record Settings(
+    String endpoint,
+    String host,
+
+    // HTTP Configuration
+    boolean httpEnabled,
+    int httpPort,
+
+    // HTTPS Configuration
+    boolean httpsEnabled,
+    int httpsPort,
+    String keystorePath,
+    String keystorePassword,
+    String keystoreType,
+
+    // Script Logging
+    boolean scriptLoggingEnabled,
+    String scriptLogLevel,
+    String scriptLogDirectory,
+
+    // Portable / encrypted config
+    boolean configEncryptionEnabled,
+    String configEncryptionPassword,
+
+    // REST API authentication
+    boolean restAuthEnabled,
+    String restAuthUser,
+    String restAuthPasswordHash
+) {
+
+    public Settings() {
+        this(
+            "opc.tcp://opcuaserver.com:48010",
+            "http://localhost:8080",
+            true,
+            8081,
+            false,
+            8443,
+            "",
+            "",
+            "JKS",
+            true,
+            "INFO",
+            AppPaths.configFile("logs").toString(),
+            false,
+            "",
+            false,
+            "admin",
+            ""
+        );
+    }
+
+    // Backward compatibility - old constructor
+    public Settings(String listener, String endpoint, String host) {
+        this(endpoint, host, true, 8081, false, 8443, "", "", "JKS",
+             true, "INFO", AppPaths.configFile("logs").toString(),
+             false, "", false, "admin", "");
+    }
+
+    public static Settings defaults() {
+        return new Settings();
+    }
+
+    public ScriptLogger.Level getLogLevel() {
+        try {
+            return ScriptLogger.Level.valueOf(scriptLogLevel.toUpperCase());
+        } catch (Exception e) {
+            return ScriptLogger.Level.INFO;
+        }
+    }
+
+    public boolean hasRestPassword() {
+        return restAuthPasswordHash != null && !restAuthPasswordHash.isBlank();
+    }
+}
diff --git a/src/main/java/de/opcua/app/config/SettingsService.java b/src/main/java/de/opcua/app/config/SettingsService.java
new file mode 100644
index 0000000..d549413
--- /dev/null
+++ b/src/main/java/de/opcua/app/config/SettingsService.java
@@ -0,0 +1,128 @@
+package de.opcua.app.config;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Map;
+
+public final class SettingsService {
+  private static final Path FILE = AppPaths.configFile("settings.json");
+  private static final Path LEGACY_CWD_FILE = Path.of("settings.json").toAbsolutePath().normalize();
+  private final ObjectMapper om = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);
+
+  public Path getFile() { return FILE; }
+
+  public Settings load() {
+    AppPaths.ensureConfigDirectory();
+    migrateLegacySettingsIfNeeded();
+    if (!Files.exists(FILE)) return Settings.defaults();
+    try {
+      @SuppressWarnings("unchecked")
+      Map<String, Object> m = om.readValue(Files.readString(FILE), Map.class);
+      Settings defaults = Settings.defaults();
+
+      String endpoint = (String) m.getOrDefault("Endpoint", m.getOrDefault("endpoint", defaults.endpoint()));
+      String host = (String) m.getOrDefault("Host", m.getOrDefault("host", defaults.host()));
+
+      boolean httpEnabled = m.containsKey("httpEnabled") ? bool(m.get("httpEnabled"), true) : true;
+      int httpPort = intValue(m.get("httpPort"), 8081);
+      if (!m.containsKey("httpPort") && m.containsKey("httpUrl")) {
+        try {
+          String url = (String) m.get("httpUrl");
+          if (url.contains(":")) {
+            String portStr = url.substring(url.lastIndexOf(":") + 1).replace("/", "");
+            httpPort = Integer.parseInt(portStr);
+          }
+        } catch (Exception ignored) {}
+      }
+
+      boolean httpsEnabled = bool(m.getOrDefault("httpsEnabled", defaults.httpsEnabled()), defaults.httpsEnabled());
+      int httpsPort = intValue(m.get("httpsPort"), defaults.httpsPort());
+      String keystorePath = string(m.getOrDefault("keystorePath", defaults.keystorePath()));
+      String keystorePassword = string(m.getOrDefault("keystorePassword", defaults.keystorePassword()));
+      String keystoreType = string(m.getOrDefault("keystoreType", defaults.keystoreType()));
+
+      boolean loggingEnabled = bool(m.getOrDefault("scriptLoggingEnabled", defaults.scriptLoggingEnabled()), defaults.scriptLoggingEnabled());
+      String logLevel = string(m.getOrDefault("scriptLogLevel", defaults.scriptLogLevel()));
+      String logDir = string(m.getOrDefault("scriptLogDirectory", defaults.scriptLogDirectory()));
+      if (logDir == null || logDir.isBlank() || logDir.contains(".opcua-gui")) logDir = defaults.scriptLogDirectory();
+
+      boolean configEncryptionEnabled = bool(m.getOrDefault("configEncryptionEnabled", defaults.configEncryptionEnabled()), defaults.configEncryptionEnabled());
+      String configEncryptionPassword = string(m.getOrDefault("configEncryptionPassword", defaults.configEncryptionPassword()));
+
+      boolean restAuthEnabled = bool(m.getOrDefault("restAuthEnabled", defaults.restAuthEnabled()), defaults.restAuthEnabled());
+      String restAuthUser = string(m.getOrDefault("restAuthUser", defaults.restAuthUser()));
+      String restAuthPasswordHash = string(m.getOrDefault("restAuthPasswordHash", defaults.restAuthPasswordHash()));
+      // Backward compatibility if a plain REST password was temporarily written by an older build.
+      String plainRestPassword = string(m.get("restAuthPassword"));
+      if ((restAuthPasswordHash == null || restAuthPasswordHash.isBlank()) && plainRestPassword != null && !plainRestPassword.isBlank()) {
+        restAuthPasswordHash = ConfigSecurity.sha256(plainRestPassword);
+      }
+
+      return new Settings(
+          endpoint, host,
+          httpEnabled, httpPort,
+          httpsEnabled, httpsPort, keystorePath, keystorePassword, keystoreType,
+          loggingEnabled, logLevel, logDir,
+          configEncryptionEnabled, configEncryptionPassword,
+          restAuthEnabled, restAuthUser == null || restAuthUser.isBlank() ? "admin" : restAuthUser, restAuthPasswordHash == null ? "" : restAuthPasswordHash
+      );
+    } catch (Exception e) {
+      System.err.println("Error loading settings from " + FILE + ": " + e.getMessage());
+      e.printStackTrace();
+      return Settings.defaults();
+    }
+  }
+
+  public void save(Settings s) throws IOException {
+    AppPaths.ensureConfigDirectory();
+    Map<String, Object> m = new java.util.LinkedHashMap<>();
+    m.put("Endpoint", s.endpoint());
+    m.put("Host", s.host());
+    m.put("httpEnabled", s.httpEnabled());
+    m.put("httpPort", s.httpPort());
+    m.put("httpsEnabled", s.httpsEnabled());
+    m.put("httpsPort", s.httpsPort());
+    m.put("keystorePath", s.keystorePath());
+    m.put("keystorePassword", s.keystorePassword());
+    m.put("keystoreType", s.keystoreType());
+    m.put("scriptLoggingEnabled", s.scriptLoggingEnabled());
+    m.put("scriptLogLevel", s.scriptLogLevel());
+    m.put("scriptLogDirectory", s.scriptLogDirectory());
+    m.put("configDirectory", AppPaths.configDirectory().toString());
+    m.put("configEncryptionEnabled", s.configEncryptionEnabled());
+    m.put("configEncryptionPassword", s.configEncryptionPassword());
+    m.put("restAuthEnabled", s.restAuthEnabled());
+    m.put("restAuthUser", s.restAuthUser());
+    m.put("restAuthPasswordHash", s.restAuthPasswordHash());
+    Files.writeString(FILE, om.writeValueAsString(m));
+  }
+
+  private void migrateLegacySettingsIfNeeded() {
+    try {
+      if (Files.exists(FILE)) return;
+      if (Files.exists(LEGACY_CWD_FILE) && !LEGACY_CWD_FILE.equals(FILE)) {
+        Files.createDirectories(FILE.getParent());
+        Files.copy(LEGACY_CWD_FILE, FILE);
+        System.out.println("[Config] Migrated settings.json to " + FILE);
+      }
+    } catch (Exception e) {
+      System.err.println("[Config] Legacy settings migration skipped: " + e.getMessage());
+    }
+  }
+
+  private String string(Object v) { return v == null ? null : String.valueOf(v); }
+  private boolean bool(Object v, boolean fallback) {
+    if (v == null) return fallback;
+    if (v instanceof Boolean b) return b;
+    return Boolean.parseBoolean(String.valueOf(v));
+  }
+  private int intValue(Object v, int fallback) {
+    if (v == null) return fallback;
+    if (v instanceof Number n) return n.intValue();
+    try { return Integer.parseInt(String.valueOf(v)); } catch (Exception e) { return fallback; }
+  }
+}
diff --git a/src/main/java/de/opcua/app/logging/ScriptLogger.java b/src/main/java/de/opcua/app/logging/ScriptLogger.java
new file mode 100644
index 0000000..cfb02e3
--- /dev/null
+++ b/src/main/java/de/opcua/app/logging/ScriptLogger.java
@@ -0,0 +1,276 @@
+package de.opcua.app.logging;
+
+import java.io.*;
+import java.nio.file.*;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.zip.GZIPOutputStream;
+
+/**
+ * JavaScript execution logger with rotation and debug levels
+ */
+public class ScriptLogger {
+    
+    public enum Level {
+        DEBUG(0), INFO(1), WARN(2), ERROR(3), OFF(4);
+        
+        private final int value;
+        Level(int value) { this.value = value; }
+        public int getValue() { return value; }
+    }
+    
+    private final String logDirectory;
+    private final String logFileName;
+    private final long maxFileSize;
+    private final int maxBackupFiles;
+    private Level currentLevel;
+    private boolean enabled;
+    
+    private PrintWriter writer;
+    private long currentFileSize;
+    private final ReentrantLock lock;
+    private final DateTimeFormatter formatter;
+    
+    public ScriptLogger(String logDirectory, boolean enabled, Level level) {
+        this.logDirectory = logDirectory;
+        this.logFileName = "javascript.log";
+        this.maxFileSize = 10 * 1024 * 1024; // 10 MB
+        this.maxBackupFiles = 5;
+        this.currentLevel = level;
+        this.enabled = enabled;
+        this.lock = new ReentrantLock();
+        this.formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS");
+        
+        if (enabled) {
+            initializeLogger();
+        }
+    }
+    
+    private void initializeLogger() {
+        try {
+            Path logDir = Paths.get(logDirectory);
+            if (!Files.exists(logDir)) {
+                Files.createDirectories(logDir);
+            }
+            
+            Path logFile = Paths.get(logDirectory, logFileName);
+            if (Files.exists(logFile)) {
+                currentFileSize = Files.size(logFile);
+            } else {
+                currentFileSize = 0;
+            }
+            
+            writer = new PrintWriter(new BufferedWriter(
+                new FileWriter(logFile.toFile(), true)), true);
+            
+            log(Level.INFO, "JavaScript logger initialized");
+            
+        } catch (IOException e) {
+            System.err.println("[ScriptLogger] Failed to initialize: " + e.getMessage());
+            enabled = false;
+        }
+    }
+    
+    public void setEnabled(boolean enabled) {
+        lock.lock();
+        try {
+            if (enabled && !this.enabled) {
+                initializeLogger();
+            } else if (!enabled && this.enabled) {
+                closeLogger();
+            }
+            this.enabled = enabled;
+        } finally {
+            lock.unlock();
+        }
+    }
+    
+    public void setLevel(Level level) {
+        this.currentLevel = level;
+    }
+    
+    public boolean isEnabled() {
+        return enabled;
+    }
+    
+    public Level getLevel() {
+        return currentLevel;
+    }
+    
+    public void debug(String message, Object... args) {
+        log(Level.DEBUG, message, args);
+    }
+    
+    public void info(String message, Object... args) {
+        log(Level.INFO, message, args);
+    }
+    
+    public void warn(String message, Object... args) {
+        log(Level.WARN, message, args);
+    }
+    
+    public void error(String message, Object... args) {
+        log(Level.ERROR, message, args);
+    }
+    
+    public void error(String message, Throwable throwable) {
+        if (!shouldLog(Level.ERROR)) return;
+        
+        log(Level.ERROR, message);
+        
+        lock.lock();
+        try {
+            if (writer != null) {
+                throwable.printStackTrace(writer);
+                writer.flush();
+            }
+        } finally {
+            lock.unlock();
+        }
+    }
+    
+    private void log(Level level, String message, Object... args) {
+        if (!shouldLog(level)) return;
+        
+        String formattedMessage = args.length > 0 
+            ? String.format(message, args) 
+            : message;
+        
+        String logLine = String.format("[%s] [%s] %s%n",
+            LocalDateTime.now().format(formatter),
+            level.name(),
+            formattedMessage
+        );
+        
+        lock.lock();
+        try {
+            if (writer != null) {
+                writer.print(logLine);
+                writer.flush();
+                
+                currentFileSize += logLine.length();
+                
+                if (currentFileSize >= maxFileSize) {
+                    rotateLog();
+                }
+            }
+            
+            // Also print to console in debug mode
+            if (level == Level.DEBUG || level == Level.ERROR) {
+                System.out.print(logLine);
+            }
+            
+        } finally {
+            lock.unlock();
+        }
+    }
+    
+    private boolean shouldLog(Level level) {
+        return enabled && level.getValue() >= currentLevel.getValue();
+    }
+    
+    private void rotateLog() {
+        try {
+            closeLogger();
+            
+            Path currentLog = Paths.get(logDirectory, logFileName);
+            
+            // Delete oldest backup if exists
+            Path oldestBackup = Paths.get(logDirectory, 
+                logFileName + "." + maxBackupFiles + ".gz");
+            if (Files.exists(oldestBackup)) {
+                Files.delete(oldestBackup);
+            }
+            
+            // Shift existing backups
+            for (int i = maxBackupFiles - 1; i >= 1; i--) {
+                Path from = Paths.get(logDirectory, logFileName + "." + i + ".gz");
+                Path to = Paths.get(logDirectory, logFileName + "." + (i + 1) + ".gz");
+                if (Files.exists(from)) {
+                    Files.move(from, to, StandardCopyOption.REPLACE_EXISTING);
+                }
+            }
+            
+            // Compress and move current log to .1.gz
+            Path backupLog = Paths.get(logDirectory, logFileName + ".1.gz");
+            compressFile(currentLog, backupLog);
+            
+            // Delete original
+            Files.delete(currentLog);
+            
+            // Reinitialize
+            currentFileSize = 0;
+            writer = new PrintWriter(new BufferedWriter(
+                new FileWriter(currentLog.toFile(), true)), true);
+            
+            log(Level.INFO, "Log rotated - new file created");
+            
+        } catch (IOException e) {
+            System.err.println("[ScriptLogger] Failed to rotate log: " + e.getMessage());
+        }
+    }
+    
+    private void compressFile(Path source, Path target) throws IOException {
+        try (FileInputStream fis = new FileInputStream(source.toFile());
+             FileOutputStream fos = new FileOutputStream(target.toFile());
+             GZIPOutputStream gzipOS = new GZIPOutputStream(fos)) {
+            
+            byte[] buffer = new byte[8192];
+            int len;
+            while ((len = fis.read(buffer)) != -1) {
+                gzipOS.write(buffer, 0, len);
+            }
+        }
+    }
+    
+    private void closeLogger() {
+        if (writer != null) {
+            writer.close();
+            writer = null;
+        }
+    }
+    
+    public void close() {
+        lock.lock();
+        try {
+            closeLogger();
+        } finally {
+            lock.unlock();
+        }
+    }
+    
+    /**
+     * Log script execution with context
+     */
+    public void logScriptExecution(String actionName, String nodeId, 
+                                   String trigger, String value, 
+                                   boolean success, String result) {
+        if (!enabled) return;
+        
+        Level level = success ? Level.INFO : Level.ERROR;
+        
+        log(level, 
+            "Script: %s | Node: %s | Trigger: %s | Value: %s | Success: %s | Result: %s",
+            actionName, nodeId, trigger, value, success, result
+        );
+    }
+    
+    /**
+     * Get current log file content (last N lines)
+     */
+    public String getRecentLogs(int lines) {
+        Path logFile = Paths.get(logDirectory, logFileName);
+        if (!Files.exists(logFile)) {
+            return "No logs available";
+        }
+        
+        try {
+            java.util.List<String> allLines = Files.readAllLines(logFile);
+            int start = Math.max(0, allLines.size() - lines);
+            return String.join("\n", allLines.subList(start, allLines.size()));
+        } catch (IOException e) {
+            return "Error reading logs: " + e.getMessage();
+        }
+    }
+}
diff --git a/src/main/java/de/opcua/app/model/NodeAction.java b/src/main/java/de/opcua/app/model/NodeAction.java
new file mode 100644
index 0000000..7764388
--- /dev/null
+++ b/src/main/java/de/opcua/app/model/NodeAction.java
@@ -0,0 +1,207 @@
+package de.opcua.app.model;
+
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Represents an action that can be executed when an OPC UA node value changes.
+ * Supports trigger rules plus an optional JavaScript condition that is evaluated
+ * before the main script is started. NodeIds used by scripts should be written
+ * explicitly in the JavaScript, e.g. var Temperature = opc.read("ns=2;s=Temperature");
+ */
+public class NodeAction {
+
+    public enum TriggerType {
+        ON_CHANGE,        // Execute on any value change
+        ON_TRUE,          // Execute when value becomes true/non-zero
+        ON_FALSE,         // Execute when value becomes false/zero
+        ON_EVEN,          // Execute when value is even
+        ON_ODD,           // Execute when value is odd
+        ON_VALUE,         // Execute when value equals specific value
+        ON_GREATER_THAN,  // Execute when value > threshold
+        ON_LESS_THAN,     // Execute when value < threshold
+        ON_INTERVAL       // Execute on timer interval
+    }
+
+    private String nodeId;
+    private String actionName;
+    private TriggerType triggerType;
+    private String script;             // JavaScript code to execute
+    private boolean initEnabled;       // Execute initScript at startup/connect before event runs
+    private String initScript;         // JavaScript code for reglogin/session/token initialization
+    private String triggerValue;       // For ON_VALUE, ON_GREATER_THAN, ON_LESS_THAN
+    private int intervalMs;            // For ON_INTERVAL
+    private boolean enabled;
+    private String lastValue;          // Track last value for change detection
+
+    // Extended scripting / condition support. conditionNodeIds/nodeAliases are kept
+    // for backwards compatibility with older saved actions and UI helper snippets.
+    private boolean conditionEnabled;
+    private String conditionScript;
+    private List<String> conditionNodeIds;
+    private Map<String, String> nodeAliases; // nodeId -> variable alias used in JavaScript
+
+    public NodeAction() {
+        this.enabled = true;
+        this.triggerType = TriggerType.ON_CHANGE;
+        this.conditionEnabled = false;
+        this.conditionScript = "";
+        this.initEnabled = false;
+        this.initScript = "";
+        this.conditionNodeIds = new ArrayList<>();
+        this.nodeAliases = new LinkedHashMap<>();
+    }
+
+    public NodeAction(String nodeId, String actionName, TriggerType triggerType, String script) {
+        this();
+        this.nodeId = nodeId;
+        this.actionName = actionName;
+        this.triggerType = triggerType;
+        this.script = script;
+    }
+
+    /**
+     * Check if this action should be triggered based on the new value.
+     * The optional JavaScript condition is evaluated later in ActionService,
+     * because it may need fresh values from additional NodeIds.
+     */
+    public boolean shouldTrigger(String newValue) {
+        if (!enabled) return false;
+
+        try {
+            switch (triggerType) {
+                case ON_CHANGE:
+                    boolean changed = !Objects.equals(lastValue, newValue);
+                    lastValue = newValue;
+                    return changed;
+
+                case ON_TRUE:
+                    return isTruthyValue(newValue);
+
+                case ON_FALSE:
+                    return !isTruthyValue(newValue);
+
+                case ON_EVEN:
+                    return isEven(newValue);
+
+                case ON_ODD:
+                    return isOdd(newValue);
+
+                case ON_VALUE:
+                    return Objects.equals(newValue, triggerValue);
+
+                case ON_GREATER_THAN:
+                    return compareNumeric(newValue, triggerValue) > 0;
+
+                case ON_LESS_THAN:
+                    return compareNumeric(newValue, triggerValue) < 0;
+
+                case ON_INTERVAL:
+                    // Interval-based triggers are handled separately
+                    return false;
+
+                default:
+                    return false;
+            }
+        } catch (Exception e) {
+            System.err.println("Error checking trigger for action " + actionName + ": " + e.getMessage());
+            return false;
+        }
+    }
+
+    private boolean isTruthyValue(String value) {
+        if (value == null || value.trim().isEmpty()) return false;
+
+        if ("true".equalsIgnoreCase(value.trim())) return true;
+        if ("false".equalsIgnoreCase(value.trim())) return false;
+
+        try {
+            double num = Double.parseDouble(value.trim());
+            return num != 0.0;
+        } catch (NumberFormatException e) {
+            return true;
+        }
+    }
+
+    private boolean isEven(String value) {
+        try {
+            long num = Long.parseLong(value.trim());
+            return num % 2 == 0;
+        } catch (NumberFormatException e) {
+            return false;
+        }
+    }
+
+    private boolean isOdd(String value) {
+        try {
+            long num = Long.parseLong(value.trim());
+            return num % 2 != 0;
+        } catch (NumberFormatException e) {
+            return false;
+        }
+    }
+
+    private int compareNumeric(String value1, String value2) {
+        try {
+            double num1 = Double.parseDouble(value1.trim());
+            double num2 = Double.parseDouble(value2.trim());
+            return Double.compare(num1, num2);
+        } catch (NumberFormatException e) {
+            return value1.compareTo(value2);
+        }
+    }
+
+    public String getNodeId() { return nodeId; }
+    public void setNodeId(String nodeId) { this.nodeId = nodeId; }
+
+    public String getActionName() { return actionName; }
+    public void setActionName(String actionName) { this.actionName = actionName; }
+
+    public TriggerType getTriggerType() { return triggerType; }
+    public void setTriggerType(TriggerType triggerType) { this.triggerType = triggerType; }
+
+    public String getScript() { return script; }
+    public void setScript(String script) { this.script = script; }
+
+    public boolean isInitEnabled() { return initEnabled; }
+    public void setInitEnabled(boolean initEnabled) { this.initEnabled = initEnabled; }
+
+    public String getInitScript() { return initScript; }
+    public void setInitScript(String initScript) { this.initScript = initScript; }
+
+    public String getTriggerValue() { return triggerValue; }
+    public void setTriggerValue(String triggerValue) { this.triggerValue = triggerValue; }
+
+    public int getIntervalMs() { return intervalMs; }
+    public void setIntervalMs(int intervalMs) { this.intervalMs = intervalMs; }
+
+    public boolean isEnabled() { return enabled; }
+    public void setEnabled(boolean enabled) { this.enabled = enabled; }
+
+    public String getLastValue() { return lastValue; }
+    public void setLastValue(String lastValue) { this.lastValue = lastValue; }
+
+    public boolean isConditionEnabled() { return conditionEnabled; }
+    public void setConditionEnabled(boolean conditionEnabled) { this.conditionEnabled = conditionEnabled; }
+
+    public String getConditionScript() { return conditionScript; }
+    public void setConditionScript(String conditionScript) { this.conditionScript = conditionScript; }
+
+    public List<String> getConditionNodeIds() { return conditionNodeIds; }
+    public void setConditionNodeIds(List<String> conditionNodeIds) {
+        this.conditionNodeIds = conditionNodeIds != null ? new ArrayList<>(conditionNodeIds) : new ArrayList<>();
+    }
+
+    public Map<String, String> getNodeAliases() { return nodeAliases; }
+    public void setNodeAliases(Map<String, String> nodeAliases) {
+        this.nodeAliases = nodeAliases != null ? new LinkedHashMap<>(nodeAliases) : new LinkedHashMap<>();
+    }
+
+    @Override
+    public String toString() {
+        return actionName + " (" + triggerType + ")";
+    }
+}
diff --git a/src/main/java/de/opcua/app/model/NodeRow.java b/src/main/java/de/opcua/app/model/NodeRow.java
new file mode 100644
index 0000000..8f8aef9
--- /dev/null
+++ b/src/main/java/de/opcua/app/model/NodeRow.java
@@ -0,0 +1,75 @@
+package de.opcua.app.model;
+
+import javafx.beans.property.*;
+
+public class NodeRow {
+
+    private final BooleanProperty selected = new SimpleBooleanProperty(false);
+    private final StringProperty displayName = new SimpleStringProperty("");
+    private final StringProperty nodeType = new SimpleStringProperty("");
+    private final StringProperty nodeId = new SimpleStringProperty("");
+    private final StringProperty namespaceIndex = new SimpleStringProperty("");
+    private final StringProperty identifierType = new SimpleStringProperty("");
+    private final StringProperty value = new SimpleStringProperty("");
+
+    public NodeRow() {}
+
+    public NodeRow(
+            boolean selected,
+            String displayName,
+            String nodeType,
+            String nodeId,
+            String namespaceIndex,
+            String identifierType,
+            String value
+    ) {
+        this.selected.set(selected);
+        this.displayName.set(displayName);
+        this.nodeType.set(nodeType);
+        this.nodeId.set(nodeId);
+        this.namespaceIndex.set(namespaceIndex);
+        this.identifierType.set(identifierType);
+        this.value.set(value);
+    }
+
+    // --- Properties ------------------------------------------------
+
+    public BooleanProperty selectedProperty() { return selected; }
+    public StringProperty displayNameProperty() { return displayName; }
+    public StringProperty nodeTypeProperty() { return nodeType; }
+    public StringProperty nodeIdProperty() { return nodeId; }
+    public StringProperty namespaceIndexProperty() { return namespaceIndex; }
+    public StringProperty identifierTypeProperty() { return identifierType; }
+    public StringProperty valueProperty() { return value; }
+
+    // --- Convenience ----------------------------------------------
+
+    public boolean isSelected() {
+        return selected.get();
+    }
+
+    public void setSelected(boolean v) {
+        selected.set(v);
+    }
+
+    public String getNodeId() {
+        return nodeId.get();
+    }
+    
+    public String getDisplayName() {
+        return displayName.get();
+    }
+    
+    public String getValue() {
+        return value.get();
+    }
+
+    public void setValue(String v) {
+        value.set(v);
+    }
+
+    /** 🔥 DAS IST DER FIX FÜR <err> */
+    public boolean isReadable() {
+        return "Variable".equalsIgnoreCase(nodeType.get());
+    }
+}
diff --git a/src/main/java/de/opcua/app/model/ScriptTemplate.java b/src/main/java/de/opcua/app/model/ScriptTemplate.java
new file mode 100644
index 0000000..b65466b
--- /dev/null
+++ b/src/main/java/de/opcua/app/model/ScriptTemplate.java
@@ -0,0 +1,47 @@
+package de.opcua.app.model;
+
+/**
+ * User configurable JavaScript action template.
+ *
+ * Templates are rendered with fixed NodeIds before they are inserted into an
+ * action script. They are not executed directly and do not depend on checkbox
+ * state at runtime.
+ */
+public class ScriptTemplate {
+    private String id;
+    private String name;
+    private String script;
+    private boolean enabled = true;
+    private boolean builtIn = false;
+    private long updatedAt;
+
+    public ScriptTemplate() {
+    }
+
+    public ScriptTemplate(String id, String name, String script, boolean enabled, boolean builtIn) {
+        this.id = id;
+        this.name = name;
+        this.script = script;
+        this.enabled = enabled;
+        this.builtIn = builtIn;
+        this.updatedAt = System.currentTimeMillis();
+    }
+
+    public String getId() { return id; }
+    public void setId(String id) { this.id = id; }
+
+    public String getName() { return name; }
+    public void setName(String name) { this.name = name; }
+
+    public String getScript() { return script; }
+    public void setScript(String script) { this.script = script; }
+
+    public boolean isEnabled() { return enabled; }
+    public void setEnabled(boolean enabled) { this.enabled = enabled; }
+
+    public boolean isBuiltIn() { return builtIn; }
+    public void setBuiltIn(boolean builtIn) { this.builtIn = builtIn; }
+
+    public long getUpdatedAt() { return updatedAt; }
+    public void setUpdatedAt(long updatedAt) { this.updatedAt = updatedAt; }
+}
diff --git a/src/main/java/de/opcua/app/model/SystemInitScript.java b/src/main/java/de/opcua/app/model/SystemInitScript.java
new file mode 100644
index 0000000..e9711bd
--- /dev/null
+++ b/src/main/java/de/opcua/app/model/SystemInitScript.java
@@ -0,0 +1,39 @@
+package de.opcua.app.model;
+
+/**
+ * Global JavaScript executed for system/session initialization.
+ *
+ * This is independent from node actions. It is intended for reglogin,
+ * token refresh and values that should be available to every action via
+ * global.* (for example global.session).
+ */
+public class SystemInitScript {
+    private boolean enabled;
+    private boolean runAtProgramStart;
+    private boolean runAfterConnect;
+    private String script;
+    private long updatedAt;
+
+    public SystemInitScript() {
+        this.enabled = false;
+        this.runAtProgramStart = false;
+        this.runAfterConnect = true;
+        this.script = "";
+        this.updatedAt = System.currentTimeMillis();
+    }
+
+    public boolean isEnabled() { return enabled; }
+    public void setEnabled(boolean enabled) { this.enabled = enabled; }
+
+    public boolean isRunAtProgramStart() { return runAtProgramStart; }
+    public void setRunAtProgramStart(boolean runAtProgramStart) { this.runAtProgramStart = runAtProgramStart; }
+
+    public boolean isRunAfterConnect() { return runAfterConnect; }
+    public void setRunAfterConnect(boolean runAfterConnect) { this.runAfterConnect = runAfterConnect; }
+
+    public String getScript() { return script; }
+    public void setScript(String script) { this.script = script != null ? script : ""; }
+
+    public long getUpdatedAt() { return updatedAt; }
+    public void setUpdatedAt(long updatedAt) { this.updatedAt = updatedAt; }
+}
diff --git a/src/main/java/de/opcua/app/model/TreeNodeRef.java b/src/main/java/de/opcua/app/model/TreeNodeRef.java
new file mode 100644
index 0000000..b5440d3
--- /dev/null
+++ b/src/main/java/de/opcua/app/model/TreeNodeRef.java
@@ -0,0 +1,28 @@
+package de.opcua.app.model;
+
+public record TreeNodeRef(
+    String displayName,
+    String nodeId,
+    String browseName,
+    String nodeClass,
+    String dataType,
+    String accessLevel,
+    String referenceTypeId   // ← NEU: z.B. "i=35", "i=46", "i=47"
+) {
+    // Backward-compatible constructors
+    public TreeNodeRef(String displayName, String nodeId) {
+        this(displayName, nodeId, displayName, "Unknown", "Unknown", "ReadWrite", null);
+    }
+
+    // Bestehender 6-Arg-Konstruktor bleibt kompatibel
+    public TreeNodeRef(String displayName, String nodeId, String browseName,
+                       String nodeClass, String dataType, String accessLevel) {
+        this(displayName, nodeId, browseName, nodeClass, dataType, accessLevel, null);
+    }
+
+    @Override
+    public String toString() {
+        if (displayName == null || displayName.isBlank()) return nodeId;
+        return displayName;
+    }
+}
diff --git a/src/main/java/de/opcua/app/opc/OpcUaService.java b/src/main/java/de/opcua/app/opc/OpcUaService.java
new file mode 100644
index 0000000..d6e38d6
--- /dev/null
+++ b/src/main/java/de/opcua/app/opc/OpcUaService.java
@@ -0,0 +1,192 @@
+package de.opcua.app.opc;
+
+import de.opcua.app.model.TreeNodeRef;
+import org.eclipse.milo.opcua.sdk.client.OpcUaClient;
+import org.eclipse.milo.opcua.stack.core.Identifiers;
+import org.eclipse.milo.opcua.stack.core.types.builtin.NodeId;
+import org.eclipse.milo.opcua.stack.core.types.builtin.Variant;
+import org.eclipse.milo.opcua.stack.core.types.structured.ReferenceDescription;
+import org.eclipse.milo.opcua.stack.core.types.enumerated.TimestampsToReturn;
+
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+public final class OpcUaService {
+
+    private volatile OpcUaClient client;
+
+    // ------------------------------------------------------------
+    // CONNECTION
+    // ------------------------------------------------------------
+
+    public boolean isConnected() {
+        return client != null;
+    }
+
+    public CompletableFuture<Void> connect(String endpointUrl) {
+        try {
+            OpcUaClient c = OpcUaClient.create(endpointUrl);
+            this.client = c;
+            return c.connect().thenApply(ignored -> null);
+        } catch (Exception e) {
+            CompletableFuture<Void> failed = new CompletableFuture<>();
+            failed.completeExceptionally(e);
+            return failed;
+        }
+    }
+
+    public CompletableFuture<Void> disconnect() {
+        OpcUaClient c = client;
+        client = null;
+        if (c == null) return CompletableFuture.completedFuture(null);
+        return c.disconnect().thenApply(ignored -> null);
+    }
+
+    // ------------------------------------------------------------
+    // BROWSE — async (für GUI)
+    // ------------------------------------------------------------
+
+    public CompletableFuture<List<TreeNodeRef>> browseRoot() {
+        return browseNode(Identifiers.RootFolder);
+    }
+
+    public CompletableFuture<List<TreeNodeRef>> browse(String nodeId) {
+        return browseNode(NodeId.parse(nodeId));
+    }
+
+    private CompletableFuture<List<TreeNodeRef>> browseNode(NodeId nodeId) {
+        try {
+            List<ReferenceDescription> refs = client.getAddressSpace().browse(nodeId);
+            return CompletableFuture.completedFuture(mapRefs(refs));
+        } catch (Exception e) {
+            CompletableFuture<List<TreeNodeRef>> f = new CompletableFuture<>();
+            f.completeExceptionally(e);
+            return f;
+        }
+    }
+
+    // ------------------------------------------------------------
+    // BROWSE — synchron (nur für Digital Twin Build Thread!)
+    // ------------------------------------------------------------
+
+    public List<TreeNodeRef> browseRootSync() throws Exception {
+        return browseNodeSync(Identifiers.RootFolder);
+    }
+
+    public List<TreeNodeRef> browseSync(String nodeId) throws Exception {
+        return browseNodeSync(NodeId.parse(nodeId));
+    }
+
+    private List<TreeNodeRef> browseNodeSync(NodeId nodeId) throws Exception {
+        List<ReferenceDescription> refs = client.getAddressSpace().browse(nodeId);
+        return mapRefs(refs);
+    }
+
+    // ── shared mapping ───────────────────────────────────────────────────────
+    private List<TreeNodeRef> mapRefs(List<ReferenceDescription> refs) {
+        return refs.stream()
+                .map(r -> {
+                    String displayName = r.getDisplayName() != null
+                            ? r.getDisplayName().getText()
+                            : r.getBrowseName().getName();
+                    String nodeClass = r.getNodeClass() != null
+                            ? r.getNodeClass().name() : "Unknown";
+                    String dataType = "Unknown";
+                    try {
+                        if (r.getTypeDefinition() != null)
+                            dataType = r.getTypeDefinition().toParseableString();
+                    } catch (Exception ignored) {}
+                    String referenceTypeId = null;
+                    try {
+                        if (r.getReferenceTypeId() != null)
+                            referenceTypeId = r.getReferenceTypeId().toParseableString();
+                    } catch (Exception ignored) {}
+                    return new TreeNodeRef(
+                            displayName,
+                            r.getNodeId().toParseableString(),
+                            r.getBrowseName().getName(),
+                            nodeClass, dataType, "ReadWrite", referenceTypeId);
+                })
+                .collect(Collectors.toList());
+    }
+
+    // ------------------------------------------------------------
+    // READ VALUE — async (für GUI)
+    // ------------------------------------------------------------
+
+    public CompletableFuture<String> readValue(String nodeId) {
+        NodeId id = NodeId.parse(nodeId);
+        return client.readValue(0, TimestampsToReturn.Neither, id)
+                .thenApply(dv -> {
+                    if (dv == null || dv.getValue() == null) return "<null>";
+                    Object v = dv.getValue().getValue();
+                    return v == null ? "<null>" : v.toString();
+                });
+    }
+
+    // ------------------------------------------------------------
+    // READ VALUE — synchron (nur für Digital Twin Build Thread!)
+    // ------------------------------------------------------------
+
+    public String readValueSync(String nodeId) throws Exception {
+        NodeId id = NodeId.parse(nodeId);
+        var dv = client.readValue(0, TimestampsToReturn.Neither, id)
+                .get(5, TimeUnit.SECONDS);
+        if (dv == null || dv.getValue() == null) return "<null>";
+        Object v = dv.getValue().getValue();
+        return v == null ? "<null>" : v.toString();
+    }
+
+    // ------------------------------------------------------------
+    // WRITE VALUE
+    // ------------------------------------------------------------
+
+    public CompletableFuture<Boolean> writeValue(String nodeId, Object value) {
+        NodeId id = NodeId.parse(nodeId);
+        try {
+            Variant variant = convertToVariant(value);
+            org.eclipse.milo.opcua.stack.core.types.builtin.DataValue dataValue =
+                new org.eclipse.milo.opcua.stack.core.types.builtin.DataValue(variant);
+
+            return client.writeValue(id, dataValue)
+                    .thenApply(statusCode -> {
+                        if (statusCode != null && statusCode.isGood()) {
+                            return true;
+                        }
+                        System.err.println("Write failed for " + nodeId + ": " + statusCode);
+                        return false;
+                    })
+                    .exceptionally(ex -> {
+                        System.err.println("Write exception for " + nodeId + ": " + ex.getMessage());
+                        return false;
+                    });
+        } catch (Exception e) {
+            CompletableFuture<Boolean> failed = new CompletableFuture<>();
+            failed.completeExceptionally(e);
+            return failed;
+        }
+    }
+
+    private Variant convertToVariant(Object value) {
+        if (value == null) return new Variant(null);
+        if (value instanceof String) {
+            String str = (String) value;
+            try {
+                return str.contains(".")
+                        ? new Variant(Double.parseDouble(str))
+                        : new Variant(Integer.parseInt(str));
+            } catch (NumberFormatException e) {
+                return new Variant(str);
+            }
+        } else if (value instanceof Integer) return new Variant((Integer) value);
+        else if (value instanceof Long)      return new Variant((Long) value);
+        else if (value instanceof Double)    return new Variant((Double) value);
+        else if (value instanceof Float)     return new Variant((Float) value);
+        else if (value instanceof Boolean)   return new Variant((Boolean) value);
+        else if (value instanceof Short)     return new Variant((Short) value);
+        else if (value instanceof Byte)      return new Variant((Byte) value);
+        return new Variant(value.toString());
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/de/opcua/app/rest/HelpPageHandler.class b/src/main/java/de/opcua/app/rest/HelpPageHandler.class
new file mode 100644
index 0000000..c9dfc03
Binary files /dev/null and b/src/main/java/de/opcua/app/rest/HelpPageHandler.class differ
diff --git a/src/main/java/de/opcua/app/rest/HelpPageHandler.java b/src/main/java/de/opcua/app/rest/HelpPageHandler.java
new file mode 100644
index 0000000..ceebdf7
--- /dev/null
+++ b/src/main/java/de/opcua/app/rest/HelpPageHandler.java
@@ -0,0 +1,312 @@
+package de.opcua.app.rest;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+import java.io.IOException;
+
+public class HelpPageHandler implements HttpHandler {
+
+    @Override
+    public void handle(HttpExchange exchange) throws IOException {
+        String query = exchange.getRequestURI().getQuery();
+        boolean english = query != null && query.contains("lang=en");
+        String html = english ? buildEnglishHelp() : buildGermanHelp();
+        byte[] bytes = html.getBytes("UTF-8");
+        exchange.getResponseHeaders().set("Content-Type", "text/html; charset=UTF-8");
+        exchange.sendResponseHeaders(200, bytes.length);
+        exchange.getResponseBody().write(bytes);
+        exchange.getResponseBody().close();
+    }
+
+    private String commonStyle() {
+        return """
+            <style>
+              :root{--bg:#f2f6fb;--card:#fff;--text:#17202a;--muted:#667085;--blue:#007aff;--green:#34c759;--orange:#ff9500;--red:#ff3b30;--border:#d9e2ec;--code:#0f172a;--codeText:#e2e8f0}
+              @media(prefers-color-scheme:dark){:root{--bg:#0b1220;--card:#111827;--text:#e5e7eb;--muted:#9ca3af;--border:#374151;--code:#020617;--codeText:#e2e8f0}}
+              *{box-sizing:border-box} body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.55}
+              header{background:linear-gradient(135deg,#007aff,#34c759);color:#fff;padding:28px 20px;box-shadow:0 2px 12px rgba(0,0,0,.18)}
+              .wrap{max-width:1220px;margin:0 auto;padding:20px}.top{display:flex;gap:14px;align-items:center}.logo{width:54px;height:54px;border-radius:14px;box-shadow:0 3px 10px rgba(0,0,0,.25)}
+              h1{margin:0;font-size:clamp(26px,4vw,38px)} h2{margin:34px 0 12px;color:var(--blue)} h3{margin:20px 0 8px}.muted{color:var(--muted)}
+              .card{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:18px;margin:16px 0;box-shadow:0 1px 4px rgba(0,0,0,.05)}
+              .grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:14px}.badge{display:inline-block;border-radius:999px;padding:3px 10px;font-size:12px;font-weight:700;color:#fff;margin-right:8px}.get{background:var(--green)}.post{background:var(--orange)}.delete{background:var(--red)}
+              pre{background:var(--code);color:var(--codeText);border-radius:12px;padding:16px;overflow:auto;line-height:1.45} code{font-family:"Cascadia Code","SF Mono",Consolas,monospace;font-size:13px}
+              table{width:100%;border-collapse:collapse;margin-top:10px}th,td{border-bottom:1px solid var(--border);padding:10px;text-align:left;vertical-align:top}th{color:var(--muted);font-size:12px;text-transform:uppercase}
+              a{color:var(--blue);text-decoration:none}.nav a{margin-right:14px}.note{border-left:4px solid var(--orange);background:rgba(255,149,0,.12);padding:12px;border-radius:8px}
+            </style>
+            """;
+    }
+
+    private String buildGermanHelp() {
+        return """
+            <!doctype html><html lang="de"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width,initial-scale=1">
+            <title>OPC UA Client Hilfe</title><link rel="icon" href="/favicon.ico">
+            """ + commonStyle() + """
+            </head><body>
+            <header><div class="wrap top"><img class="logo" src="/assets/opcua-client-logo.svg" alt=""><div><h1>OPC UA Client Hilfe</h1><div>REST API, Script-Beispiele, RegLogin, Globals, Windows-Service und EXE-Build</div></div></div></header>
+            <main class="wrap">
+              <div class="nav card"><a href="/">Web UI</a><a href="/api/openapi.json">OpenAPI JSON</a><a href="?lang=en">English</a></div>
+
+              <h2>1. Grundprinzip</h2>
+              <div class="card">
+                <p>Die Checkboxen im Tree sind nur Code-Helfer. Das gespeicherte Script muss eigenständig bleiben, also NodeIDs direkt enthalten:</p>
+                <pre><code>var Temperatur = Number(opc.read("ns=3;s=AirConditioner_1.Temperature"));
+var Grenzwert = Number(opc.read("ns=3;s=AirConditioner_1.TemperatureSetPoint"));
+Temperatur &gt; Grenzwert</code></pre>
+                <p>Dadurch kann eine Action 1:1 kopiert, exportiert und auf einem anderen Client geladen werden.</p>
+              </div>
+
+
+
+              <h2>1a. JavaScript-Editor und Code-Generator</h2>
+              <div class="card">
+                <p>In der JavaFX-GUI und in der Weboberflaeche ist ein JavaScript-Editor eingebunden. Die Auswahl/Checkboxen erzeugen nur Codebausteine. Beim Speichern steht jede NodeId fest im Script.</p>
+                <pre><code>// Lesebaustein aus selektierter Node
+var Temperatur = Number(opc.read("ns=3;s=AirConditioner_1.Temperature"));
+
+// Schreibbaustein aus selektierter Node
+opc.write("ns=3;s=AirConditioner_1.ResultValue", result.value);</code></pre>
+                <p>Eigene Templates laden/speichern und rendern:</p>
+                <pre><code># alle Templates laden
+curl http://localhost:8081/api/script/templates
+
+# eigenes Template speichern
+curl -X POST http://localhost:8081/api/script/templates   -H "Content-Type: application/json"   -d '{
+    "name":"MES POST + OPC SET",
+    "enabled":true,
+    "script":"{{readNumberVars}}\nvar response = http.postJson(\"http://localhost:9000/api/mes\", {\n{{payloadFields}}});\nvar result = JSON.parse(response.body);\nglobal.apiResult = result;\n{{opcWritesFromResult}}"
+  }'
+
+# Template mit konkreten NodeIDs rendern
+curl -X POST http://localhost:8081/api/script/template-snippet   -H "Content-Type: application/json"   -d '{
+    "template":"MES POST + OPC SET",
+    "nodes":[
+      {"nodeId":"ns=3;s=AirConditioner_1.Temperature","alias":"Temperatur"},
+      {"nodeId":"ns=3;s=AirConditioner_1.ResultValue","alias":"ResultValue"}
+    ]
+  }'</code></pre>
+                <p>REST-Codegenerator:</p>
+                <pre><code>curl -X POST http://localhost:8081/api/script/snippet \
+  -H "Content-Type: application/json" \
+  -d '{
+    "mode":"readNumber",
+    "nodes":[
+      {"nodeId":"ns=3;s=AirConditioner_1.Temperature","alias":"Temperatur"}
+    ]
+  }'</code></pre>
+                <p>Im Dialog <b>Create New Action</b> werden Template-Buttons automatisch aus <b>Configuration → Script Templates / Button-Vorlagen</b> erzeugt. GET, POST und SET sind nur Standard-Templates und können dort geändert, deaktiviert oder durch eigene Templates ergänzt werden. Der Button-Name kommt aus dem Feld <b>Name / Button-Text</b>.</p>
+                <p>Beim Einfügen werden Platzhalter durch festen, kopierbaren Code ersetzt. Beispiel: Aus <code>{{readNumberVars}}</code> wird <code>var Temperatur = Number(opc.read("ns=..."));</code>; aus <code>{{opcWritesFromResult}}</code> wird <code>opc.write("ns=...", result.value);</code>.</p>
+                <pre><code>// POST Template per REST erzeugen
+curl -X POST http://localhost:8081/api/script/snippet \
+  -H "Content-Type: application/json" \
+  -d '{
+    "mode":"templatePost",
+    "nodes":[
+      {"nodeId":"ns=3;s=AirConditioner_1.Temperature","alias":"Temperatur"},
+      {"nodeId":"ns=3;s=AirConditioner_1.Humidity","alias":"Feuchte"}
+    ]
+  }'
+
+// SET/opc.write Template per REST erzeugen
+curl -X POST http://localhost:8081/api/script/snippet \
+  -H "Content-Type: application/json" \
+  -d '{
+    "mode":"templateSet",
+    "nodes":[
+      {"nodeId":"ns=3;s=AirConditioner_1.ResultValue","alias":"ResultValue"}
+    ]
+  }'</code></pre>
+              </div>
+
+              <h2>1b. Portable Config, Verschlüsselung und REST Auth</h2>
+              <div class="card">
+                <p>Alle Konfigurationen und Definitionen liegen jetzt transportabel im Unterordner der Anwendung:</p>
+                <pre><code>&lt;Anwendungsordner&gt;/config/settings.json
+&lt;Anwendungsordner&gt;/config/actions.json
+&lt;Anwendungsordner&gt;/config/system-init-script.json
+&lt;Anwendungsordner&gt;/config/script-templates.json</code></pre>
+                <p>Im Bereich <b>Configuration → Portable Config / Verschlüsselung / REST Auth</b> kann die Verschlüsselung aktiviert werden. Actions, Templates und System Init werden dann als AES-GCM Umschlag gespeichert.</p>
+                <pre><code>{
+  "encrypted" : true,
+  "algorithm" : "AES/GCM/NoPadding",
+  "kdf" : "PBKDF2WithHmacSHA256",
+  "data" : "..."
+}</code></pre>
+                <p>REST-Authentifizierung kann dort ebenfalls aktiviert werden. REST-Clients verwenden Basic Auth:</p>
+                <pre><code>curl -u admin:meinPasswort http://localhost:8081/api/status
+
+curl -u admin:meinPasswort -X POST http://localhost:8081/api/read \
+  -H "Content-Type: application/json" \
+  -d '{"nodeId":"ns=3;s=AirConditioner_1.Temperature"}'</code></pre>
+                <p>Die Web-Oberfläche fragt bei aktivierter REST Auth das Passwort automatisch ab.</p>
+                <p>REST-Endpunkte für Security-Konfiguration:</p>
+                <pre><code># Auth Status, ohne Passwort lesbar
+curl http://localhost:8081/api/auth/status
+
+# Security-Konfiguration lesen
+curl -u admin:meinPasswort http://localhost:8081/api/config/security
+
+# REST Auth aktivieren und Passwort setzen
+curl -X POST http://localhost:8081/api/config/security \
+  -H "Content-Type: application/json" \
+  -d '{
+    "restAuthEnabled": true,
+    "restAuthUser": "admin",
+    "restAuthPassword": "meinPasswort",
+    "configEncryptionEnabled": true,
+    "configEncryptionPassword": "configSecret"
+  }'</code></pre>
+              </div>
+
+              <h2>2. Globales System Init / RegLogin</h2>
+              <div class="card">
+                <p>Pflege in der JavaFX-GUI und in der Weboberfläche identisch unter <b>Configuration → System Init / RegLogin</b>. In der Weboberfläche öffnet der Button <b>⚙ Configuration</b> denselben Bereich mit <b>Aktiv</b>, <b>Bei Programmstart</b>, <b>Nach OPC Connect/Reconnect</b>, <b>RegLogin Template einfügen</b> und <b>Speichern &amp; jetzt ausführen</b>. Gespeichert wird dauerhaft unter:</p>
+                <pre><code>config/system-init-script.json</code></pre>
+                <p>Im Service-Modus wird das Script nach erfolgreichem OPC-Connect/Reconnect ausgeführt, wenn <code>runAfterConnect</code> aktiviert ist.</p>
+                <pre><code>var response = http.postJson("http://localhost:9000/api/reglogin", {
+  client: "opcua-client",
+  user: "opc",
+  password: "secret"
+});
+
+if (response.status &lt; 200 || response.status &gt;= 300) {
+  throw "RegLogin fehlgeschlagen: HTTP " + response.status + " / " + response.body;
+}
+
+var result = JSON.parse(response.body);
+
+// global: fuer alle Actions sichtbar
+global.session = result;
+global.token = result.token;
+global.apiResult = result;
+global.lastRegLogin = new Date().toISOString();
+
+log.info("RegLogin OK, Token gespeichert");</code></pre>
+              </div>
+
+              <h2>3. Action-Beispiel: OPC lesen, REST aufrufen, Ergebnis per opc.write zurückschreiben</h2>
+              <div class="card">
+                <pre><code>function readNumber(nodeId) {
+  return Number(opc.read(nodeId));
+}
+
+function callApi(temp, humidity) {
+  return http.postJson(
+    "http://localhost:9000/api/process",
+    {
+      temperature: temp,
+      humidity: humidity,
+      eventNode: event.nodeId,
+      eventValue: currentValue,
+      timestamp: new Date().toISOString()
+    },
+    {
+      Authorization: "Bearer " + global.session.token
+    }
+  );
+}
+
+function writeBack(result) {
+  opc.write("ns=3;s=AirConditioner_1.ResultValue", result.value);
+  opc.write("ns=3;s=AirConditioner_1.ResultText", result.text);
+  opc.write("ns=3;s=AirConditioner_1.ResultOk", result.ok);
+}
+
+var Temperatur = readNumber("ns=3;s=AirConditioner_1.Temperature");
+var Feuchte = readNumber("ns=3;s=AirConditioner_1.Humidity");
+
+var response = callApi(Temperatur, Feuchte);
+
+if (response.status &gt;= 200 &amp;&amp; response.status &lt; 300) {
+  var result = JSON.parse(response.body);
+
+  // Ergebnis global merken, z. B. fuer Diagnose oder Folge-Actions
+  global.apiResult = result;
+  global.lastTemperature = Temperatur;
+
+  writeBack(result);
+  log.info("REST-Ergebnis in OPC UA geschrieben", result.value);
+} else {
+  global.apiResult = { ok:false, error:response.body, status:response.status };
+  opc.write("ns=3;s=AirConditioner_1.ResultText", "REST Fehler " + response.status);
+  log.error("REST Fehler", response.status, response.body);
+}</code></pre>
+              </div>
+
+              <h2>4. Condition-Script mit Unterfunktionen</h2>
+              <div class="card">
+                <p>Ein Condition-Script muss am Ende <code>true</code> oder <code>false</code> ergeben.</p>
+                <pre><code>function valueOf(nodeId) {
+  return Number(opc.read(nodeId));
+}
+
+var Temperatur = valueOf("ns=3;s=AirConditioner_1.Temperature");
+var Grenzwert = valueOf("ns=3;s=AirConditioner_1.TemperatureSetPoint");
+
+Temperatur &gt; Grenzwert</code></pre>
+              </div>
+
+              <h2>5. REST API Übersicht</h2>
+              <div class="card">
+                <table><thead><tr><th>Methode</th><th>Pfad</th><th>Zweck</th></tr></thead><tbody>
+                  <tr><td><span class="badge get">GET</span></td><td><code>/api/auth/status</code></td><td>REST Auth Status, ohne Auth lesbar</td></tr>
+                  <tr><td><span class="badge get">GET</span>/<span class="badge post">POST</span></td><td><code>/api/config/security</code></td><td>Portable Config, Verschlüsselung und REST Auth lesen/speichern</td></tr>
+                  <tr><td><span class="badge get">GET</span></td><td><code>/api/status</code></td><td>OPC-Verbindungsstatus</td></tr>
+                  <tr><td><span class="badge get">GET</span></td><td><code>/api/health</code></td><td>Health Check</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/read</code></td><td>Node lesen</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/write</code></td><td>Node schreiben</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/browse</code></td><td>Eine Ebene browsen</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/browse-tree</code></td><td>Teilbaum browsen</td></tr>
+                  <tr><td><span class="badge get">GET</span></td><td><code>/api/export</code></td><td>Digital Twin JSON exportieren</td></tr>
+                  <tr><td><span class="badge get">GET</span></td><td><code>/api/actions</code></td><td>Actions laden</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/actions</code></td><td>Action speichern</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/actions/test</code></td><td>Action testen</td></tr>
+                  <tr><td><span class="badge get">GET</span></td><td><code>/api/system-init</code></td><td>System Init Script laden</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/system-init</code></td><td>System Init Script speichern</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/system-init/run</code></td><td>System Init/RegLogin manuell ausführen</td></tr>
+                  <tr><td><span class="badge get">GET</span></td><td><code>/api/globals</code></td><td>Globale Variablen lesen</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/globals</code></td><td>Globale Variable setzen</td></tr>
+                  <tr><td><span class="badge post">POST</span></td><td><code>/api/script/snippet</code></td><td>JavaScript Codebausteine mit festen NodeIDs erzeugen</td></tr>
+                </tbody></table>
+              </div>
+
+              <h2>6. REST-Beispiele mit curl</h2>
+              <div class="grid">
+                <div class="card"><h3>Lesen</h3><pre><code>curl -X POST http://localhost:8081/api/read \
+  -H "Content-Type: application/json" \
+  -d '{"nodeId":"ns=3;s=AirConditioner_1.Temperature"}'</code></pre></div>
+                <div class="card"><h3>Schreiben</h3><pre><code>curl -X POST http://localhost:8081/api/write \
+  -H "Content-Type: application/json" \
+  -d '{"nodeId":"ns=3;s=AirConditioner_1.ResultText","value":"OK"}'</code></pre></div>
+                <div class="card"><h3>RegLogin manuell starten</h3><pre><code>curl -X POST http://localhost:8081/api/system-init/run \
+  -H "Content-Type: application/json" \
+  -d '{"reason":"manual-reglogin","force":true}'</code></pre></div>
+                <div class="card"><h3>Globals lesen</h3><pre><code>curl http://localhost:8081/api/globals</code></pre></div>
+              </div>
+
+              <h2>7. Windows Service Wrapper</h2>
+              <div class="card">
+                <p>Im Ordner <code>windows-service</code> liegen WinSW-Konfiguration und Batch-Dateien. WinSW erwartet EXE und XML nebeneinander. Die offizielle WinSW-Nutzung ist: EXE herunterladen/umbenennen, XML danebenlegen, dann <code>install</code> und <code>start</code> ausführen.</p>
+                <pre><code>cd windows-service
+install-service.bat
+start-service.bat
+status-service.bat</code></pre>
+                <p class="note">Der Service startet die Anwendung mit <code>java -jar opcua-gui-1.0.0.jar --service</code>. RegLogin läuft nach erfolgreichem OPC-Connect automatisch, wenn im System-Init-Script <code>runAfterConnect</code> aktiv ist.</p>
+              </div>
+
+              <h2>8. EXE bauen</h2>
+              <div class="card">
+                <pre><code>mvn -Pwindows-exe clean package -DskipTests
+
+# Ergebnis:
+target/opcua-gui.exe</code></pre>
+              </div>
+            </main></body></html>
+            """;
+    }
+
+    private String buildEnglishHelp() {
+        return buildGermanHelp().replace("lang=\"de\"", "lang=\"en\"")
+                .replace("OPC UA Client Hilfe", "OPC UA Client Help")
+                .replace("REST API, Script-Beispiele, RegLogin, Globals, Windows-Service und EXE-Build", "REST API, script examples, RegLogin, globals, Windows service and EXE build");
+    }
+}
diff --git a/src/main/java/de/opcua/app/rest/OpcUaRestApi.java b/src/main/java/de/opcua/app/rest/OpcUaRestApi.java
new file mode 100644
index 0000000..46bf7ee
--- /dev/null
+++ b/src/main/java/de/opcua/app/rest/OpcUaRestApi.java
@@ -0,0 +1,1327 @@
+package de.opcua.app.rest;
+
+import com.sun.net.httpserver.*;
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.model.SystemInitScript;
+import de.opcua.app.model.ScriptTemplate;
+import de.opcua.app.service.ActionService;
+import de.opcua.app.service.SystemInitScriptService;
+import de.opcua.app.service.ScriptTemplateService;
+import de.opcua.app.scripting.Store;
+import de.opcua.app.config.AppPaths;
+import de.opcua.app.config.ConfigSecurity;
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.scripting.ScriptSnippetBuilder;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import java.io.*;
+import java.net.InetSocketAddress;
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Collectors;
+import de.opcua.app.model.TreeNodeRef;
+
+public class OpcUaRestApi {
+
+    private final OpcUaService opcService;
+    private final ObjectMapper mapper;
+    private final ActionService actionService;
+    private final SystemInitScriptService systemInitScripts;
+    private final ScriptTemplateService scriptTemplates;
+    private final SettingsService settingsService;
+    private HttpServer server;
+    private final int port;
+
+    // ── Digital Twin Cache — NUR für Export ─────────────────────────────────
+    private volatile List<Map<String, Object>> cachedDigitalTwin = null;
+    private volatile long digitalTwinBuildTime = 0;
+    private final AtomicBoolean building = new AtomicBoolean(false);
+
+    // ── NEU: View-NodeId Cache ────────────────────────────────────────────────
+    // Wird beim Browse befüllt, damit verschachtelte Views korrekt erkannt werden.
+    // Standard OPC-UA: i=87 = ViewsFolder
+    private final Set<String> knownViewNodeIds = ConcurrentHashMap.newKeySet();
+
+    public OpcUaRestApi(OpcUaService opcService, int port) {
+        this(opcService, port, new ActionService(opcService, new Store()));
+    }
+
+    public OpcUaRestApi(OpcUaService opcService, int port, ActionService actionService) {
+        this.opcService = opcService;
+        this.port       = port;
+        this.actionService = actionService;
+        this.systemInitScripts = new SystemInitScriptService();
+        this.scriptTemplates = new ScriptTemplateService();
+        this.settingsService = new SettingsService();
+        this.mapper     = new ObjectMapper();
+        // Standard-Views vorregistrieren
+        knownViewNodeIds.add("i=87"); // ViewsFolder
+        knownViewNodeIds.add("ns=0;i=87"); // ViewsFolder fully qualified
+    }
+
+    // ── Public API ───────────────────────────────────────────────────────────
+
+    public void triggerDigitalTwinBuild() {
+        if (!building.compareAndSet(false, true)) {
+            System.out.println("[Digital Twin] Build already in progress, skipping.");
+            return;
+        }
+        cachedDigitalTwin = null;
+
+        Thread t = new Thread(() -> {
+            System.out.println("[Digital Twin] Build started...");
+            long start = System.currentTimeMillis();
+            try {
+                List<Map<String, Object>> tree = browseRecursive(null, null, 0, new LinkedHashSet<>());
+                cachedDigitalTwin    = tree;
+                digitalTwinBuildTime = System.currentTimeMillis();
+                System.out.printf("[Digital Twin] ✅ Cached %d nodes in %dms%n",
+                        countNodes(tree), System.currentTimeMillis() - start);
+            } catch (Exception e) {
+                System.err.println("[Digital Twin] ❌ " + e.getMessage());
+                e.printStackTrace();
+            } finally {
+                building.set(false);
+            }
+        }, "digital-twin-builder");
+        t.setDaemon(true);
+        t.start();
+    }
+
+    public void setDigitalTwin(List<Map<String, Object>> tree) {
+        this.cachedDigitalTwin    = tree;
+        this.digitalTwinBuildTime = System.currentTimeMillis();
+    }
+
+    public void start() throws IOException {
+        server = HttpServer.create(new InetSocketAddress(port), 0);
+
+        // ── Sofort verfügbar (kein Twin nötig) ──────────────────────────────
+        server.createContext("/api/auth/status", new AuthStatusHandler());
+        server.createContext("/api/config/security", new ConfigSecurityHandler());
+        server.createContext("/api/status",      new StatusHandler());
+        server.createContext("/api/health",      new HealthHandler());
+        server.createContext("/api/read",        new ReadHandler());
+        server.createContext("/api/write",       new WriteHandler());
+        server.createContext("/api/browse",      new BrowseHandler());      // ← sofort, 1 Ebene
+        server.createContext("/api/browse-tree", new BrowseTreeHandler());  // ← lazy, pro Klick
+        server.createContext("/api/system-init", new SystemInitHandler());
+        server.createContext("/api/system-init/run", new RunSystemInitHandler());
+        server.createContext("/api/actions/init", new InitActionsHandler());
+        server.createContext("/api/actions",     new ActionsHandler());
+        server.createContext("/api/actions/delete", new DeleteActionHandler());
+        server.createContext("/api/actions/enable", new EnableActionHandler());
+        server.createContext("/api/actions/test", new TestActionHandler());
+        server.createContext("/api/globals",     new GlobalsHandler());
+        server.createContext("/api/script/snippet", new ScriptSnippetHandler());
+        server.createContext("/api/script/templates", new ScriptTemplatesHandler());
+        server.createContext("/api/script/template-snippet", new ScriptTemplateSnippetHandler());
+        server.createContext("/api/openapi.json", new OpenApiHandler());
+
+        // Statische Assets fuer Web-UI, Hilfe und Favicon
+        server.createContext("/assets",          new StaticAssetHandler());
+        server.createContext("/favicon.ico",     new FaviconHandler());
+
+        // ── Twin-abhängig ────────────────────────────────────────────────────
+        server.createContext("/api/export",      new ExportHandler());      // ← Twin als Download
+        server.createContext("/api/twin-status", new TwinStatusHandler());  // ← Build-Fortschritt
+
+        server.createContext("/help",            new de.opcua.app.rest.HelpPageHandler());
+        server.createContext("/",                new WebInterfaceHandler());
+
+        server.setExecutor(Executors.newFixedThreadPool(10));
+        server.start();
+
+        System.out.println("[REST API] Started on port " + port);
+        System.out.println("[Web UI]   http://localhost:" + port + "/");
+    }
+
+    public void stop() {
+        if (server != null) server.stop(0);
+    }
+
+    // ── Browse helpers ───────────────────────────────────────────────────────
+
+    /**
+     * Für Export: rekursiv, sequenziell.
+     * parentNodeId wird benötigt, um View-Kinder korrekt mit "Organizes" zu markieren.
+     */
+    private List<Map<String, Object>> browseRecursive(String nodeId, String parentNodeId,
+                                                       int depth, Set<String> path)
+            throws Exception {
+        System.out.println("[Twin] depth=" + depth + " node=" + nodeId);
+
+        Set<String> currentPath = new LinkedHashSet<>(path);
+        if (nodeId != null) {
+            if (currentPath.contains(nodeId)) {
+                return new ArrayList<>();
+            }
+            currentPath.add(nodeId);
+        }
+
+        List<TreeNodeRef> children = nodeId == null
+                ? opcService.browseRootSync()
+                : opcService.browseSync(nodeId);
+
+        System.out.println("[Twin] got " + children.size() + " children");
+
+        List<Map<String, Object>> result = new ArrayList<>();
+        for (var child : children) {
+            Map<String, Object> node = new LinkedHashMap<>();
+            node.put("nodeId",        child.nodeId());
+            node.put("displayName",   child.displayName());
+            node.put("browseName",    child.browseName());
+            node.put("nodeClass",     child.nodeClass());
+
+            if ("View".equals(child.nodeClass())) {
+                knownViewNodeIds.add(child.nodeId());
+            }
+
+            node.put("referenceType", determineReferenceType(child, nodeId));
+            node.put("dataType",      child.dataType());
+            node.put("accessLevel",   child.accessLevel());
+
+            if ("Variable".equals(child.nodeClass())) {
+                try {
+                    node.put("value", opcService.readValueSync(child.nodeId()));
+                } catch (Exception e) {
+                    node.put("value", null);
+                }
+            }
+
+            if (currentPath.contains(child.nodeId())) {
+                node.put("cycle", true);
+                node.put("children", new ArrayList<>());
+            } else {
+                node.put("children", browseRecursive(child.nodeId(), nodeId, depth + 1, currentPath));
+            }
+            result.add(node);
+        }
+        return result;
+    }
+
+    // ── NEU: Referenz-Typ Ermittlung ─────────────────────────────────────────
+    /**
+     * Bestimmt den OPC-UA Referenz-Typ eines Knotens.
+     *
+     * Priorität:
+     *  1. Service liefert referenceTypeId direkt → auflösen
+     *  2. Parent ist eine View → immer "Organizes" (NodeIds.Organizes = i=35)
+     *  3. Heuristik nach nodeClass
+     *
+     * OPC-UA Standard-NodeIds:
+     *   i=35  Organizes          – View → Kinder; Ordner-Hierarchien
+     *   i=46  HasProperty        – Variable als Eigenschaft eines Objects
+     *   i=47  HasComponent       – Object/Method als Komponente eines Objects
+     */
+    private String determineReferenceType(TreeNodeRef child, String parentNodeId) {
+        // 1. Service liefert es direkt
+        if (child.referenceTypeId() != null && !child.referenceTypeId().isBlank()) {
+            return resolveReferenceTypeId(child.referenceTypeId());
+        }
+
+        // 2. Parent ist eine View → Organizes (i=35)
+        if (isViewNode(parentNodeId)) {
+            return "Organizes"; // NodeIds.Organizes = i=35
+        }
+
+        // 3. Heuristik nach nodeClass
+        String nodeClass  = child.nodeClass() != null ? child.nodeClass() : "";
+        String browseName = child.browseName() != null ? child.browseName() : "";
+
+        return switch (nodeClass) {
+            case "Variable" -> "HasProperty";    // NodeIds.HasProperty  = i=46
+            case "Object"   -> "HasComponent";   // NodeIds.HasComponent = i=47
+            case "Method"   -> "HasComponent";
+            case "View"     -> "Organizes";      // NodeIds.Organizes    = i=35
+            default -> browseName.endsWith("Type") ? "HasTypeDefinition" : "HasComponent";
+        };
+    }
+
+    /** Löst numerische OPC-UA Standard-NodeIds auf lesbare Namen auf. */
+    private String resolveReferenceTypeId(String refTypeId) {
+        String normalized = refTypeId != null && refTypeId.startsWith("ns=0;")
+                ? refTypeId.substring("ns=0;".length())
+                : refTypeId;
+        return switch (normalized) {
+            case "i=33" -> "HierarchicalReferences";
+            case "i=35" -> "Organizes";           // NodeIds.Organizes
+            case "i=36" -> "HasEventSource";
+            case "i=40" -> "HasTypeDefinition";
+            case "i=44" -> "HasEncoding";
+            case "i=45" -> "HasSubtype";
+            case "i=46" -> "HasProperty";         // NodeIds.HasProperty
+            case "i=47" -> "HasComponent";        // NodeIds.HasComponent
+            case "i=48" -> "HasNotifier";
+            default     -> refTypeId;             // unbekannte IDs direkt zurückgeben
+        };
+    }
+
+    /** Prüft, ob eine NodeId eine bekannte View ist. */
+    private boolean isViewNode(String nodeId) {
+        if (nodeId == null) return false;
+        return knownViewNodeIds.contains(nodeId);
+    }
+
+    private int countNodes(List<Map<String, Object>> tree) {
+        int count = tree.size();
+        for (var node : tree) {
+            @SuppressWarnings("unchecked")
+            var ch = (List<Map<String, Object>>) node.get("children");
+            if (ch != null) count += countNodes(ch);
+        }
+        return count;
+    }
+
+    // ════════════════════════════════════════════════════════════════════════
+    // Base Handler
+    // ════════════════════════════════════════════════════════════════════════
+
+    private abstract class BaseHandler implements HttpHandler {
+        @Override
+        public void handle(HttpExchange exchange) throws IOException {
+            exchange.getResponseHeaders().add("Access-Control-Allow-Origin",  "*");
+            exchange.getResponseHeaders().add("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
+            exchange.getResponseHeaders().add("Access-Control-Allow-Headers", "Content-Type, Authorization, X-OPCUA-Password");
+            if ("OPTIONS".equals(exchange.getRequestMethod())) {
+                exchange.sendResponseHeaders(204, -1); return;
+            }
+            try {
+                if (requiresAuthentication(exchange) && !isAuthenticated(exchange)) {
+                    sendAuthRequired(exchange);
+                    return;
+                }
+                handleRequest(exchange);
+            }
+            catch (Exception e) { sendError(exchange, 500, "Error: " + e.getMessage()); }
+        }
+
+        protected boolean requiresAuthentication(HttpExchange exchange) { return true; }
+
+        protected abstract void handleRequest(HttpExchange exchange) throws Exception;
+
+        protected void sendJson(HttpExchange exchange, Object data) throws IOException {
+            byte[] bytes = mapper.writeValueAsBytes(data);
+            exchange.getResponseHeaders().set("Content-Type", "application/json");
+            exchange.sendResponseHeaders(200, bytes.length);
+            try (OutputStream os = exchange.getResponseBody()) { os.write(bytes); }
+        }
+
+        protected void sendError(HttpExchange exchange, int code, String msg) throws IOException {
+            byte[] bytes = mapper.writeValueAsBytes(Map.of("success", false, "error", msg));
+            exchange.getResponseHeaders().set("Content-Type", "application/json");
+            exchange.sendResponseHeaders(code, bytes.length);
+            try (OutputStream os = exchange.getResponseBody()) { os.write(bytes); }
+        }
+
+        protected Map<String, Object> parseBody(HttpExchange exchange) throws IOException {
+            try (InputStream is = exchange.getRequestBody()) {
+                return mapper.readValue(is, Map.class);
+            }
+        }
+    }
+
+    private boolean isAuthenticated(HttpExchange exchange) {
+        Settings settings = settingsService.load();
+        if (!settings.restAuthEnabled() || !settings.hasRestPassword()) return true;
+
+        String xPassword = exchange.getRequestHeaders().getFirst("X-OPCUA-Password");
+        if (xPassword != null && ConfigSecurity.matchesPassword(xPassword, settings.restAuthPasswordHash())) return true;
+
+        String auth = exchange.getRequestHeaders().getFirst("Authorization");
+        if (auth == null || auth.isBlank()) return false;
+        try {
+            if (auth.regionMatches(true, 0, "Basic ", 0, 6)) {
+                String decoded = new String(Base64.getDecoder().decode(auth.substring(6).trim()), StandardCharsets.UTF_8);
+                int colon = decoded.indexOf(':');
+                String user = colon >= 0 ? decoded.substring(0, colon) : "";
+                String password = colon >= 0 ? decoded.substring(colon + 1) : decoded;
+                String expectedUser = settings.restAuthUser() == null || settings.restAuthUser().isBlank() ? "admin" : settings.restAuthUser();
+                return expectedUser.equals(user) && ConfigSecurity.matchesPassword(password, settings.restAuthPasswordHash());
+            }
+            if (auth.regionMatches(true, 0, "Bearer ", 0, 7)) {
+                String token = auth.substring(7).trim();
+                return ConfigSecurity.matchesPassword(token, settings.restAuthPasswordHash());
+            }
+        } catch (Exception ignored) {}
+        return false;
+    }
+
+    private void sendAuthRequired(HttpExchange exchange) throws IOException {
+        exchange.getResponseHeaders().set("WWW-Authenticate", "Basic realm=\"OPC UA REST API\"");
+        byte[] bytes = mapper.writeValueAsBytes(Map.of("success", false, "authRequired", true, "error", "REST authentication required"));
+        exchange.getResponseHeaders().set("Content-Type", "application/json");
+        exchange.sendResponseHeaders(401, bytes.length);
+        try (OutputStream os = exchange.getResponseBody()) { os.write(bytes); }
+    }
+
+    private class AuthStatusHandler extends BaseHandler {
+        @Override protected boolean requiresAuthentication(HttpExchange exchange) { return false; }
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            Settings s = settingsService.load();
+            sendJson(exchange, Map.of(
+                    "success", true,
+                    "restAuthEnabled", s.restAuthEnabled() && s.hasRestPassword(),
+                    "restAuthUser", s.restAuthUser() == null || s.restAuthUser().isBlank() ? "admin" : s.restAuthUser(),
+                    "configDirectory", AppPaths.configDirectory().toString()
+            ));
+        }
+    }
+
+    private class ConfigSecurityHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            Settings current = settingsService.load();
+            if ("GET".equals(exchange.getRequestMethod())) {
+                sendJson(exchange, Map.of(
+                        "success", true,
+                        "configDirectory", AppPaths.configDirectory().toString(),
+                        "settingsFile", settingsService.getFile().toString(),
+                        "configEncryptionEnabled", current.configEncryptionEnabled(),
+                        "configEncryptionPasswordSet", current.configEncryptionPassword() != null && !current.configEncryptionPassword().isBlank(),
+                        "restAuthEnabled", current.restAuthEnabled(),
+                        "restAuthUser", current.restAuthUser(),
+                        "restAuthPasswordSet", current.hasRestPassword()
+                ));
+                return;
+            }
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "GET or POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String newConfigPassword = firstNonBlank(string(body.get("configEncryptionPassword")), current.configEncryptionPassword());
+            String newRestPassword = string(body.get("restAuthPassword"));
+            String restHash = newRestPassword != null && !newRestPassword.isBlank()
+                    ? ConfigSecurity.sha256(newRestPassword)
+                    : current.restAuthPasswordHash();
+            Settings updated = new Settings(
+                    current.endpoint(), current.host(),
+                    current.httpEnabled(), current.httpPort(),
+                    current.httpsEnabled(), current.httpsPort(), current.keystorePath(), current.keystorePassword(), current.keystoreType(),
+                    current.scriptLoggingEnabled(), current.scriptLogLevel(), current.scriptLogDirectory(),
+                    booleanValue(body.get("configEncryptionEnabled"), current.configEncryptionEnabled()),
+                    newConfigPassword,
+                    booleanValue(body.get("restAuthEnabled"), current.restAuthEnabled()),
+                    firstNonBlank(string(body.get("restAuthUser")), current.restAuthUser(), "admin"),
+                    restHash
+            );
+            settingsService.save(updated);
+            sendJson(exchange, Map.of(
+                    "success", true,
+                    "configDirectory", AppPaths.configDirectory().toString(),
+                    "settingsFile", settingsService.getFile().toString(),
+                    "configEncryptionEnabled", updated.configEncryptionEnabled(),
+                    "restAuthEnabled", updated.restAuthEnabled(),
+                    "restAuthUser", updated.restAuthUser(),
+                    "restAuthPasswordSet", updated.hasRestPassword()
+            ));
+        }
+    }
+
+    // ── /api/status ──────────────────────────────────────────────────────────
+    private class StatusHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            sendJson(exchange, Map.of(
+                "connected", opcService.isConnected(),
+                "timestamp", System.currentTimeMillis()
+            ));
+        }
+    }
+
+    // ── /api/health ──────────────────────────────────────────────────────────
+    private class HealthHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            sendJson(exchange, Map.of("status", "ok"));
+        }
+    }
+
+    // ── /api/read ────────────────────────────────────────────────────────────
+    private class ReadHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = (String) body.get("nodeId");
+            if (nodeId == null) { sendError(exchange, 400, "nodeId required"); return; }
+            String value = opcService.readValue(nodeId).get(5, TimeUnit.SECONDS);
+            sendJson(exchange, Map.of("success", true, "nodeId", nodeId,
+                    "value", value, "timestamp", System.currentTimeMillis()));
+        }
+    }
+
+    // ── /api/write ───────────────────────────────────────────────────────────
+    private class WriteHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = (String) body.get("nodeId");
+            Object value  = body.get("value");
+            if (nodeId == null || value == null) { sendError(exchange, 400, "nodeId and value required"); return; }
+            boolean ok = opcService.writeValue(nodeId, value).get(5, TimeUnit.SECONDS);
+            sendJson(exchange, Map.of("success", ok, "nodeId", nodeId, "written", ok));
+        }
+    }
+
+    // ── /api/browse  (eine Ebene, sofort) ────────────────────────────────────
+    private class BrowseHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = (String) body.get("nodeId");
+
+            var kids = nodeId == null
+                    ? opcService.browseRoot().get(10, TimeUnit.SECONDS)
+                    : opcService.browse(nodeId).get(10, TimeUnit.SECONDS);
+
+            List<Map<String, Object>> list = new ArrayList<>();
+            for (var c : kids) {
+                // ── NEU: View-NodeIds beim Browse registrieren ───────────────
+                if ("View".equals(c.nodeClass())) {
+                    knownViewNodeIds.add(c.nodeId());
+                }
+                Map<String, Object> m = new LinkedHashMap<>();
+                m.put("nodeId",        c.nodeId());
+                m.put("displayName",   c.displayName());
+                m.put("browseName",    c.browseName());
+                m.put("nodeClass",     c.nodeClass());
+                m.put("referenceType", determineReferenceType(c, nodeId)); // ← NEU
+                m.put("dataType",      c.dataType());
+                m.put("accessLevel",   c.accessLevel());
+                m.put("hasChildren",   true); // konservativ; Browser expandiert bei Klick
+                list.add(m);
+            }
+            sendJson(exchange, Map.of("success", true, "nodeId",
+                    nodeId != null ? nodeId : "root", "children", list));
+        }
+    }
+
+    // ── /api/browse-tree  (lazy, eine Ebene für Tree-UI) ─────────────────────
+    private class BrowseTreeHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = (String) body.get("nodeId");
+
+            var kids = nodeId == null
+                    ? opcService.browseRoot().get(10, TimeUnit.SECONDS)
+                    : opcService.browse(nodeId).get(10, TimeUnit.SECONDS);
+
+            List<Map<String, Object>> list = new ArrayList<>();
+            for (var c : kids) {
+                if ("View".equals(c.nodeClass())) {
+                    knownViewNodeIds.add(c.nodeId());
+                }
+                Map<String, Object> m = new LinkedHashMap<>();
+                m.put("nodeId",        c.nodeId());
+                m.put("displayName",   c.displayName());
+                m.put("browseName",    c.browseName());
+                m.put("nodeClass",     c.nodeClass());
+                m.put("referenceType", determineReferenceType(c, nodeId));
+                m.put("dataType",      c.dataType());
+                m.put("accessLevel",   c.accessLevel());
+                if ("Variable".equals(c.nodeClass())) {
+                    try {
+                        m.put("value", opcService.readValue(c.nodeId()).get(5, TimeUnit.SECONDS));
+                    } catch (Exception e) { m.put("value", null); }
+                }
+                list.add(m);
+            }
+            sendJson(exchange, Map.of("success", true, "children", list));
+        }
+    }
+
+    // ── /api/actions ──────────────────────────────────────────────────────────
+    private class ActionsHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if ("GET".equals(exchange.getRequestMethod())) {
+                List<Map<String, Object>> list = actionService.getAllActionsFlat().stream()
+                        .map(OpcUaRestApi.this::actionToDto)
+                        .collect(Collectors.toList());
+                sendJson(exchange, Map.of("success", true, "actions", list));
+                return;
+            }
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "GET or POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+
+            String nodeId = string(body.get("nodeId"));
+            String name = firstNonBlank(string(body.get("actionName")), string(body.get("name")));
+            String trigger = firstNonBlank(string(body.get("triggerType")), string(body.get("trigger")), "ON_CHANGE");
+            String script = string(body.get("script"));
+            if (nodeId == null || nodeId.isBlank() || name == null || name.isBlank() || script == null || script.isBlank()) {
+                sendError(exchange, 400, "nodeId, name/actionName and script required");
+                return;
+            }
+
+            NodeAction action = new NodeAction();
+            action.setNodeId(nodeId);
+            action.setActionName(name);
+            action.setTriggerType(NodeAction.TriggerType.valueOf(trigger));
+            action.setScript(script);
+            action.setInitEnabled(booleanValue(body.get("initEnabled"), false));
+            action.setInitScript(string(body.get("initScript")));
+            action.setTriggerValue(firstNonBlank(string(body.get("triggerValue")), string(body.get("value"))));
+            action.setIntervalMs(intValue(firstNonBlank(string(body.get("intervalMs")), string(body.get("interval"))), 1000));
+            action.setEnabled(booleanValue(body.get("enabled"), true));
+            action.setConditionEnabled(booleanValue(body.get("conditionEnabled"), false));
+            action.setConditionScript(string(body.get("conditionScript")));
+            action.setConditionNodeIds(stringList(body.get("conditionNodeIds")));
+            action.setNodeAliases(stringMap(body.get("nodeAliases")));
+
+            actionService.addAction(action);
+            sendJson(exchange, Map.of("success", true, "action", actionToDto(action)));
+        }
+    }
+
+    private class DeleteActionHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = string(body.get("nodeId"));
+            String name = firstNonBlank(string(body.get("actionName")), string(body.get("name")));
+            if (nodeId == null || name == null) { sendError(exchange, 400, "nodeId and actionName/name required"); return; }
+            actionService.removeAction(nodeId, name);
+            sendJson(exchange, Map.of("success", true));
+        }
+    }
+
+    private class EnableActionHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = string(body.get("nodeId"));
+            String name = firstNonBlank(string(body.get("actionName")), string(body.get("name")));
+            boolean enabled = booleanValue(body.get("enabled"), true);
+            if (nodeId == null || name == null) { sendError(exchange, 400, "nodeId and actionName/name required"); return; }
+            actionService.setActionEnabled(nodeId, name, enabled);
+            sendJson(exchange, Map.of("success", true, "enabled", enabled));
+        }
+    }
+
+    private class TestActionHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String nodeId = string(body.get("nodeId"));
+            String name = firstNonBlank(string(body.get("actionName")), string(body.get("name")));
+            String value = firstNonBlank(string(body.get("value")), "");
+            if (nodeId == null || name == null) { sendError(exchange, 400, "nodeId and actionName/name required"); return; }
+            actionService.testAction(nodeId, name, value);
+            sendJson(exchange, Map.of("success", true, "queued", true));
+        }
+    }
+
+
+
+
+    private class SystemInitHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if ("GET".equals(exchange.getRequestMethod())) {
+                SystemInitScript config = systemInitScripts.load();
+                sendJson(exchange, Map.of(
+                        "success", true,
+                        "config", systemInitToDto(config),
+                        "file", systemInitScripts.getFilePath()
+                ));
+                return;
+            }
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "GET or POST required"); return; }
+
+            Map<String, Object> body = parseBody(exchange);
+            SystemInitScript config = systemInitScripts.load();
+            if (body.containsKey("enabled")) config.setEnabled(booleanValue(body.get("enabled"), config.isEnabled()));
+            if (body.containsKey("runAtProgramStart")) config.setRunAtProgramStart(booleanValue(body.get("runAtProgramStart"), config.isRunAtProgramStart()));
+            if (body.containsKey("runAfterConnect")) config.setRunAfterConnect(booleanValue(body.get("runAfterConnect"), config.isRunAfterConnect()));
+            if (body.containsKey("script")) config.setScript(string(body.get("script")));
+
+            systemInitScripts.save(config);
+            sendJson(exchange, Map.of(
+                    "success", true,
+                    "config", systemInitToDto(config),
+                    "file", systemInitScripts.getFilePath()
+            ));
+        }
+    }
+
+    private class RunSystemInitHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            SystemInitScript config = systemInitScripts.load();
+            String reason = firstNonBlank(string(body.get("reason")), "manual-system-init");
+            boolean force = booleanValue(body.get("force"), true);
+            boolean ignoreDisabled = booleanValue(body.get("ignoreDisabled"), false);
+
+            if (!ignoreDisabled && !config.isEnabled()) {
+                sendJson(exchange, Map.of(
+                        "success", true,
+                        "skipped", true,
+                        "reason", reason,
+                        "message", "system init script is disabled",
+                        "config", systemInitToDto(config)
+                ));
+                return;
+            }
+
+            Map<String, Object> summary = actionService.executeSystemInitScript(config.getScript(), reason, force);
+            summary.put("configFile", systemInitScripts.getFilePath());
+            sendJson(exchange, summary);
+        }
+    }
+
+    private class InitActionsHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String reason = firstNonBlank(string(body.get("reason")), "manual-api");
+            boolean force = booleanValue(body.get("force"), true);
+            Map<String, Object> summary = actionService.initializeAllActions(reason, force);
+            sendJson(exchange, summary);
+        }
+    }
+
+    private class GlobalsHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if ("GET".equals(exchange.getRequestMethod())) {
+                sendJson(exchange, Map.of(
+                        "success", true,
+                        "globals", actionService.getScriptEngine().getGlobalScope().snapshot()
+                ));
+                return;
+            }
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "GET or POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            var global = actionService.getScriptEngine().getGlobalScope();
+
+            if (booleanValue(body.get("clear"), false)) {
+                global.clear();
+                sendJson(exchange, Map.of("success", true, "globals", global.snapshot()));
+                return;
+            }
+
+            String remove = firstNonBlank(string(body.get("remove")), string(body.get("delete")));
+            if (remove != null) {
+                Object removed = global.remove(remove);
+                Map<String, Object> response = new LinkedHashMap<>();
+                response.put("success", true);
+                response.put("removed", remove);
+                response.put("value", removed);
+                sendJson(exchange, response);
+                return;
+            }
+
+            String key = string(body.get("key"));
+            if (key == null || key.isBlank() || !body.containsKey("value")) {
+                sendError(exchange, 400, "key and value required, or use clear/remove");
+                return;
+            }
+            global.set(key, body.get("value"));
+            Map<String, Object> response = new LinkedHashMap<>();
+            response.put("success", true);
+            response.put("key", key);
+            response.put("value", global.get(key));
+            sendJson(exchange, response);
+        }
+    }
+
+
+
+    private class ScriptTemplatesHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if ("GET".equals(exchange.getRequestMethod())) {
+                sendJson(exchange, Map.of(
+                        "success", true,
+                        "file", scriptTemplates.getFilePath(),
+                        "templates", scriptTemplates.load()
+                ));
+                return;
+            }
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "GET or POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+
+            if (booleanValue(body.get("resetDefaults"), false)) {
+                sendJson(exchange, Map.of(
+                        "success", true,
+                        "file", scriptTemplates.getFilePath(),
+                        "templates", scriptTemplates.resetDefaults()
+                ));
+                return;
+            }
+
+            String delete = firstNonBlank(string(body.get("delete")), string(body.get("remove")), string(body.get("id")));
+            if (booleanValue(body.get("deleteTemplate"), false) && delete != null) {
+                boolean removed = scriptTemplates.delete(delete);
+                sendJson(exchange, Map.of(
+                        "success", true,
+                        "removed", removed,
+                        "file", scriptTemplates.getFilePath(),
+                        "templates", scriptTemplates.load()
+                ));
+                return;
+            }
+
+            Object templatesObj = body.get("templates");
+            if (templatesObj instanceof List<?> list) {
+                List<ScriptTemplate> templates = new ArrayList<>();
+                for (Object item : list) {
+                    if (item instanceof Map<?, ?> map) templates.add(templateFromMap(map));
+                }
+                sendJson(exchange, Map.of(
+                        "success", true,
+                        "file", scriptTemplates.getFilePath(),
+                        "templates", scriptTemplates.save(templates)
+                ));
+                return;
+            }
+
+            ScriptTemplate saved = scriptTemplates.upsert(templateFromMap(body));
+            sendJson(exchange, Map.of(
+                    "success", true,
+                    "file", scriptTemplates.getFilePath(),
+                    "template", saved,
+                    "templates", scriptTemplates.load()
+            ));
+        }
+    }
+
+    private class ScriptTemplateSnippetHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String idOrName = firstNonBlank(string(body.get("templateId")), string(body.get("id")), string(body.get("name")), string(body.get("template")));
+            if (idOrName == null || idOrName.isBlank()) {
+                sendError(exchange, 400, "templateId, id or name required");
+                return;
+            }
+            List<ScriptSnippetBuilder.NodeSpec> specs = parseNodeSpecs(body);
+            String script = scriptTemplates.render(idOrName, specs);
+            sendJson(exchange, Map.of("success", true, "template", idOrName, "script", script));
+        }
+    }
+
+    private class ScriptSnippetHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!"POST".equals(exchange.getRequestMethod())) { sendError(exchange, 405, "POST required"); return; }
+            Map<String, Object> body = parseBody(exchange);
+            String mode = firstNonBlank(string(body.get("mode")), "readNumber");
+            String writeExpression = firstNonBlank(string(body.get("writeExpression")), string(body.get("valueExpression")), "result.value");
+
+            List<ScriptSnippetBuilder.NodeSpec> specs = parseNodeSpecs(body);
+            if (specs.isEmpty()) {
+                sendError(exchange, 400, "Provide nodeId, nodeIds or nodes");
+                return;
+            }
+
+            String script = ScriptSnippetBuilder.build(mode, specs, writeExpression);
+            sendJson(exchange, Map.of("success", true, "mode", mode, "script", script));
+        }
+    }
+
+
+    private List<ScriptSnippetBuilder.NodeSpec> parseNodeSpecs(Map<String, Object> body) {
+        List<ScriptSnippetBuilder.NodeSpec> specs = new ArrayList<>();
+        if (body == null) return specs;
+        Object nodesObj = body.get("nodes");
+        if (nodesObj instanceof List<?> list) {
+            for (Object item : list) {
+                if (item instanceof Map<?, ?> map) {
+                    String nodeId = firstNonBlank(string(map.get("nodeId")), string(map.get("id")));
+                    String alias = firstNonBlank(string(map.get("alias")), string(map.get("name")));
+                    if (nodeId != null && !nodeId.isBlank()) specs.add(new ScriptSnippetBuilder.NodeSpec(nodeId, alias));
+                } else if (item != null) {
+                    specs.add(new ScriptSnippetBuilder.NodeSpec(String.valueOf(item), null));
+                }
+            }
+        }
+        Object nodeIdsObj = body.get("nodeIds");
+        if (nodeIdsObj instanceof List<?> nodeIds) {
+            for (Object item : nodeIds) {
+                if (item != null) specs.add(new ScriptSnippetBuilder.NodeSpec(String.valueOf(item), null));
+            }
+        }
+        String singleNodeId = firstNonBlank(string(body.get("nodeId")), string(body.get("id")));
+        if (singleNodeId != null && !singleNodeId.isBlank()) {
+            specs.add(new ScriptSnippetBuilder.NodeSpec(singleNodeId, firstNonBlank(string(body.get("alias")), string(body.get("name")))));
+        }
+        return specs;
+    }
+
+    private ScriptTemplate templateFromMap(Map<?, ?> map) {
+        ScriptTemplate template = new ScriptTemplate();
+        if (map == null) return template;
+        template.setId(firstNonBlank(string(map.get("id")), string(map.get("templateId"))));
+        template.setName(firstNonBlank(string(map.get("name")), string(map.get("title")), "Template"));
+        template.setScript(firstNonBlank(string(map.get("script")), string(map.get("code")), ""));
+        template.setEnabled(booleanValue(map.get("enabled"), true));
+        template.setBuiltIn(booleanValue(map.get("builtIn"), false));
+        try { template.setUpdatedAt(Long.parseLong(firstNonBlank(string(map.get("updatedAt")), "0"))); }
+        catch (NumberFormatException ignored) { template.setUpdatedAt(0); }
+        return template;
+    }
+
+    private Map<String, Object> systemInitToDto(SystemInitScript config) {
+        Map<String, Object> dto = new LinkedHashMap<>();
+        dto.put("enabled", config.isEnabled());
+        dto.put("runAtProgramStart", config.isRunAtProgramStart());
+        dto.put("runAfterConnect", config.isRunAfterConnect());
+        dto.put("script", config.getScript());
+        dto.put("updatedAt", config.getUpdatedAt());
+        return dto;
+    }
+
+    private Map<String, Object> actionToDto(NodeAction action) {
+        Map<String, Object> dto = new LinkedHashMap<>();
+        dto.put("nodeId", action.getNodeId());
+        dto.put("actionName", action.getActionName());
+        dto.put("triggerType", action.getTriggerType().name());
+        dto.put("script", action.getScript());
+        dto.put("initEnabled", action.isInitEnabled());
+        dto.put("initScript", action.getInitScript());
+        dto.put("triggerValue", action.getTriggerValue());
+        dto.put("intervalMs", action.getIntervalMs());
+        dto.put("enabled", action.isEnabled());
+        dto.put("conditionEnabled", action.isConditionEnabled());
+        dto.put("conditionScript", action.getConditionScript());
+        dto.put("conditionNodeIds", action.getConditionNodeIds());
+        dto.put("nodeAliases", action.getNodeAliases());
+        return dto;
+    }
+
+    private String string(Object value) {
+        return value == null ? null : String.valueOf(value);
+    }
+
+    private String firstNonBlank(String... values) {
+        if (values == null) return null;
+        for (String value : values) {
+            if (value != null && !value.isBlank()) return value;
+        }
+        return null;
+    }
+
+    private int intValue(String value, int fallback) {
+        if (value == null || value.isBlank()) return fallback;
+        try { return Integer.parseInt(value.trim()); }
+        catch (NumberFormatException e) { return fallback; }
+    }
+
+    private boolean booleanValue(Object value, boolean fallback) {
+        if (value == null) return fallback;
+        if (value instanceof Boolean b) return b;
+        return Boolean.parseBoolean(String.valueOf(value));
+    }
+
+    private List<String> stringList(Object value) {
+        List<String> result = new ArrayList<>();
+        if (value instanceof List<?> list) {
+            for (Object item : list) {
+                if (item != null) result.add(String.valueOf(item));
+            }
+        }
+        return result;
+    }
+
+    private Map<String, String> stringMap(Object value) {
+        Map<String, String> result = new LinkedHashMap<>();
+        if (value instanceof Map<?, ?> map) {
+            for (Map.Entry<?, ?> entry : map.entrySet()) {
+                if (entry.getKey() != null && entry.getValue() != null) {
+                    result.put(String.valueOf(entry.getKey()), String.valueOf(entry.getValue()));
+                }
+            }
+        }
+        return result;
+    }
+
+    // ── /api/twin-status ─────────────────────────────────────────────────────
+    private class TwinStatusHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            sendJson(exchange, Map.of(
+                "ready",     cachedDigitalTwin != null,
+                "building",  building.get(),
+                "cacheTime", digitalTwinBuildTime,
+                "nodeCount", cachedDigitalTwin != null ? countNodes(cachedDigitalTwin) : 0
+            ));
+        }
+    }
+
+    // ── /api/export ──────────────────────────────────────────────────────────
+    private class ExportHandler extends BaseHandler {
+        @Override protected void handleRequest(HttpExchange exchange) throws Exception {
+            if (!opcService.isConnected()) { sendError(exchange, 503, "OPC UA not connected"); return; }
+
+            if (cachedDigitalTwin == null) {
+                byte[] bytes = mapper.writeValueAsBytes(Map.of(
+                    "success", false, "cached", false,
+                    "status",  "building",
+                    "message", "Digital Twin is still being built. Check /api/twin-status."
+                ));
+                exchange.getResponseHeaders().set("Content-Type", "application/json");
+                exchange.sendResponseHeaders(202, bytes.length);
+                try (OutputStream os = exchange.getResponseBody()) { os.write(bytes); }
+                return;
+            }
+
+            Map<String, Object> export = new LinkedHashMap<>();
+            export.put("timestamp",      digitalTwinBuildTime);
+            export.put("exportType",     "full");
+            export.put("nodeCount",      countNodes(cachedDigitalTwin));
+            export.put("tree",           cachedDigitalTwin);
+
+            String filename = "opcua-export-" + digitalTwinBuildTime + ".json";
+            exchange.getResponseHeaders().set("Content-Type", "application/json");
+            exchange.getResponseHeaders().set("Content-Disposition",
+                    "attachment; filename=\"" + filename + "\"");
+            byte[] bytes = mapper.writerWithDefaultPrettyPrinter().writeValueAsBytes(export);
+            exchange.sendResponseHeaders(200, bytes.length);
+            try (OutputStream os = exchange.getResponseBody()) { os.write(bytes); }
+        }
+    }
+
+    // ── /help ────────────────────────────────────────────────────────────────
+    private class HelpPageHandler implements HttpHandler {
+        @Override public void handle(HttpExchange exchange) throws IOException {
+            String html = """
+                <html><body>
+                <h1>OPC UA REST API</h1>
+                <h2>Sofort verfügbar</h2>
+                <ul>
+                  <li><b>GET  /api/status</b> – Verbindungsstatus</li>
+                  <li><b>GET  /api/health</b> – Health check</li>
+                  <li><b>POST /api/read</b>   – {"nodeId":"ns=2;s=Temp"}</li>
+                  <li><b>POST /api/write</b>  – {"nodeId":"ns=2;s=Set","value":"30"}</li>
+                  <li><b>POST /api/browse</b> – {"nodeId":"ns=2;i=1"} — eine Ebene sofort (inkl. referenceType)</li>
+                  <li><b>POST /api/browse-tree</b> – wie browse, mit Werten für Variables (inkl. referenceType)</li>
+                  <li><b>GET/POST /api/actions</b> – Actions lesen/anlegen inkl. Init-Script, Session und GraalVM-Scriptbedingungen</li>
+                  <li><b>GET/POST /api/globals</b> – globale Script-Variablen lesen/setzen</li>
+                </ul>
+                <h2>Digital Twin (Hintergrund-Build)</h2>
+                <ul>
+                  <li><b>GET /api/twin-status</b> – Build-Fortschritt</li>
+                  <li><b>GET /api/export</b>      – Kompletter Baum als JSON-Download</li>
+                </ul>
+                </body></html>
+                """;
+            byte[] bytes = html.getBytes("UTF-8");
+            exchange.getResponseHeaders().set("Content-Type", "text/html; charset=UTF-8");
+            exchange.sendResponseHeaders(200, bytes.length);
+            exchange.getResponseBody().write(bytes);
+            exchange.getResponseBody().close();
+        }
+    }
+
+
+    // ── /api/openapi.json ────────────────────────────────────────────────────
+    private class OpenApiHandler implements HttpHandler {
+        @Override public void handle(HttpExchange exchange) throws IOException {
+            if (!"GET".equalsIgnoreCase(exchange.getRequestMethod())) {
+                exchange.sendResponseHeaders(405, -1);
+                return;
+            }
+            String json = """
+                {
+                  "openapi": "3.0.3",
+                  "info": {
+                    "title": "OPC UA Client REST API",
+                    "version": "1.0.0",
+                    "description": "REST API fuer OPC UA Lesen, Schreiben, Browsen, Actions, System Init/RegLogin und globale Script-Variablen."
+                  },
+                  "servers": [ { "url": "/" } ],
+                  "paths": {
+                    "/api/auth/status": { "get": { "summary": "REST Auth Status lesen", "responses": { "200": { "description": "Auth Status" } } } },
+                    "/api/config/security": { "get": { "summary": "Portable Config / Verschluesselung / REST Auth lesen", "responses": { "200": { "description": "Security Config" } } }, "post": { "summary": "Portable Config / Verschluesselung / REST Auth speichern", "requestBody": { "content": { "application/json": { "schema": { "$ref": "#/components/schemas/SecurityConfig" } } } }, "responses": { "200": { "description": "Gespeichert" } } } },
+                    "/api/status": { "get": { "summary": "Verbindungsstatus lesen", "responses": { "200": { "description": "Status" } } } },
+                    "/api/health": { "get": { "summary": "Health Check", "responses": { "200": { "description": "OK" } } } },
+                    "/api/read": { "post": { "summary": "OPC UA Node lesen", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/NodeReadRequest" } } } }, "responses": { "200": { "description": "Wert" } } } },
+                    "/api/write": { "post": { "summary": "OPC UA Node schreiben", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/NodeWriteRequest" } } } }, "responses": { "200": { "description": "Schreibergebnis" } } } },
+                    "/api/browse": { "post": { "summary": "Eine Ebene browsen", "requestBody": { "content": { "application/json": { "schema": { "$ref": "#/components/schemas/BrowseRequest" } } } }, "responses": { "200": { "description": "Kinderknoten" } } } },
+                    "/api/browse-tree": { "post": { "summary": "Teilbaum browsen", "requestBody": { "content": { "application/json": { "schema": { "$ref": "#/components/schemas/BrowseRequest" } } } }, "responses": { "200": { "description": "Baum" } } } },
+                    "/api/export": { "get": { "summary": "Digital Twin als JSON exportieren", "responses": { "200": { "description": "JSON Export" } } } },
+                    "/api/twin-status": { "get": { "summary": "Digital-Twin Buildstatus", "responses": { "200": { "description": "Buildstatus" } } } },
+                    "/api/actions": { "get": { "summary": "Actions laden", "responses": { "200": { "description": "Actions" } } }, "post": { "summary": "Action speichern", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Action" } } } }, "responses": { "200": { "description": "Gespeichert" } } } },
+                    "/api/actions/test": { "post": { "summary": "Action testweise ausfuehren", "responses": { "200": { "description": "Testergebnis" } } } },
+                    "/api/actions/enable": { "post": { "summary": "Action aktivieren/deaktivieren", "responses": { "200": { "description": "Status" } } } },
+                    "/api/actions/delete": { "post": { "summary": "Action loeschen", "responses": { "200": { "description": "Geloescht" } } } },
+                    "/api/actions/init": { "post": { "summary": "Action Init-Scripts manuell ausfuehren", "responses": { "200": { "description": "Init Ergebnis" } } } },
+                    "/api/system-init": { "get": { "summary": "Globales System Init/RegLogin Script laden", "responses": { "200": { "description": "Konfiguration" } } }, "post": { "summary": "Globales System Init/RegLogin Script speichern", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/SystemInit" } } } }, "responses": { "200": { "description": "Gespeichert" } } } },
+                    "/api/system-init/run": { "post": { "summary": "System Init/RegLogin manuell ausfuehren", "responses": { "200": { "description": "Ausfuehrung" } } } },
+                    "/api/globals": { "get": { "summary": "Globale Script-Variablen lesen", "responses": { "200": { "description": "Globals" } } }, "post": { "summary": "Globale Script-Variable setzen", "requestBody": { "content": { "application/json": { "schema": { "$ref": "#/components/schemas/GlobalSetRequest" } } } }, "responses": { "200": { "description": "Gesetzt" } } } },
+                    "/api/script/templates": { "get": { "summary": "Script-Templates laden", "responses": { "200": { "description": "Templates" } } }, "post": { "summary": "Script-Templates speichern oder zuruecksetzen", "responses": { "200": { "description": "Gespeichert" } } } },
+                    "/api/script/template-snippet": { "post": { "summary": "User-Template mit festen NodeIds rendern", "responses": { "200": { "description": "JavaScript Snippet" } } } },
+                    "/api/script/snippet": { "post": { "summary": "JavaScript Codebaustein oder GET/POST/SET Template mit festen NodeIds erzeugen", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ScriptSnippetRequest" } } } }, "responses": { "200": { "description": "JavaScript Snippet" } } } }
+                  },
+                  "components": { "securitySchemes": { "basicAuth": { "type": "http", "scheme": "basic" } }, "schemas": {
+                    "NodeReadRequest": { "type": "object", "required": ["nodeId"], "properties": { "nodeId": { "type": "string", "example": "ns=3;s=AirConditioner_1.Temperature" } } },
+                    "NodeWriteRequest": { "type": "object", "required": ["nodeId", "value"], "properties": { "nodeId": { "type": "string" }, "value": { "description": "Wert als String, Zahl oder Boolean" } } },
+                    "BrowseRequest": { "type": "object", "properties": { "nodeId": { "type": "string", "description": "Optional; leer = Root" } } },
+                    "SystemInit": { "type": "object", "properties": { "enabled": { "type": "boolean" }, "runAtProgramStart": { "type": "boolean" }, "runAfterConnect": { "type": "boolean" }, "script": { "type": "string" } } },
+                    "GlobalSetRequest": { "type": "object", "required": ["key", "value"], "properties": { "key": { "type": "string" }, "value": {} } },
+                    "SecurityConfig": { "type": "object", "properties": { "configEncryptionEnabled": { "type": "boolean" }, "configEncryptionPassword": { "type": "string" }, "restAuthEnabled": { "type": "boolean" }, "restAuthUser": { "type": "string" }, "restAuthPassword": { "type": "string" } } },
+                    "ScriptSnippetRequest": { "type": "object", "required": ["mode", "nodes"], "properties": { "mode": { "type": "string", "enum": ["read", "readNumber", "write", "readWrite", "templateGet", "templatePost", "templateSet"] }, "writeExpression": { "type": "string", "example": "result.value" }, "nodes": { "type": "array", "items": { "type": "object", "properties": { "nodeId": { "type": "string" }, "alias": { "type": "string" } } } } } },
+                    "Action": { "type": "object", "properties": { "nodeId": { "type": "string" }, "name": { "type": "string" }, "enabled": { "type": "boolean" }, "initScript": { "type": "string" }, "conditionScript": { "type": "string" }, "script": { "type": "string" } } }
+                  } }
+                }
+                """;
+            byte[] bytes = json.getBytes("UTF-8");
+            exchange.getResponseHeaders().set("Content-Type", "application/json; charset=UTF-8");
+            exchange.sendResponseHeaders(200, bytes.length);
+            exchange.getResponseBody().write(bytes);
+            exchange.getResponseBody().close();
+        }
+    }
+
+    // ── /assets/* ───────────────────────────────────────────────────────────
+    private class StaticAssetHandler implements HttpHandler {
+        @Override public void handle(HttpExchange exchange) throws IOException {
+            String path = exchange.getRequestURI().getPath();
+            String name = path.substring(path.lastIndexOf('/') + 1);
+            if (name.isBlank() || name.contains("..") || name.contains("/") || name.contains("\\")) {
+                exchange.sendResponseHeaders(404, -1);
+                return;
+            }
+            sendClasspathAsset(exchange, "/styles/" + name);
+        }
+    }
+
+    private class FaviconHandler implements HttpHandler {
+        @Override public void handle(HttpExchange exchange) throws IOException {
+            sendClasspathAsset(exchange, "/styles/opcua-client.ico");
+        }
+    }
+
+    private void sendClasspathAsset(HttpExchange exchange, String resource) throws IOException {
+        try (InputStream is = getClass().getResourceAsStream(resource)) {
+            if (is == null) {
+                exchange.sendResponseHeaders(404, -1);
+                return;
+            }
+            byte[] bytes = is.readAllBytes();
+            String lower = resource.toLowerCase(Locale.ROOT);
+            String contentType = lower.endsWith(".svg") ? "image/svg+xml" :
+                    lower.endsWith(".png") ? "image/png" :
+                    lower.endsWith(".ico") ? "image/x-icon" :
+                    "application/octet-stream";
+            exchange.getResponseHeaders().set("Content-Type", contentType);
+            exchange.getResponseHeaders().set("Cache-Control", "public, max-age=86400");
+            exchange.sendResponseHeaders(200, bytes.length);
+            exchange.getResponseBody().write(bytes);
+            exchange.getResponseBody().close();
+        }
+    }
+
+    // ── / (Web Interface) ────────────────────────────────────────────────────
+    private class WebInterfaceHandler implements HttpHandler {
+        @Override public void handle(HttpExchange exchange) throws IOException {
+            String path = exchange.getRequestURI().getPath();
+            if (!path.equals("/") && !path.equals("/index.html")) {
+                exchange.sendResponseHeaders(404, -1); return;
+            }
+            InputStream is = getClass().getResourceAsStream("/web/web-interface.html");
+            String html = is != null
+                    ? new String(is.readAllBytes(), "UTF-8")
+                    : buildHtml();
+            if (is != null) is.close();
+            byte[] bytes = html.getBytes("UTF-8");
+            exchange.getResponseHeaders().set("Content-Type", "text/html; charset=UTF-8");
+            exchange.sendResponseHeaders(200, bytes.length);
+            exchange.getResponseBody().write(bytes);
+            exchange.getResponseBody().close();
+        }
+
+        private String buildHtml() {
+            return """
+                <!DOCTYPE html>
+                <html lang="de">
+                <head>
+                  <meta charset="UTF-8">
+                  <title>OPC UA Browser</title>
+                  <style>
+                    body { font-family: Arial, sans-serif; max-width: 1200px; margin: 30px auto;
+                           padding: 20px; background: #f0f2f5; }
+                    h1 { color: #2c3e50; }
+                    #status-bar { padding: 8px 14px; border-radius: 6px; margin-bottom: 16px; font-size: 14px; }
+                    .connected    { background: #d4edda; color: #155724; }
+                    .disconnected { background: #f8d7da; color: #721c24; }
+                    #toolbar { margin-bottom: 12px; display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
+                    button { padding: 8px 16px; border: none; border-radius: 5px;
+                             cursor: pointer; font-size: 14px; }
+                    #btn-root   { background: #3498db; color: #fff; }
+                    #btn-export { background: #27ae60; color: #fff; }
+                    #twin-status { font-size: 12px; color: #888; }
+                    #tree-container { background: #fff; border-radius: 8px; padding: 16px;
+                                      box-shadow: 0 2px 6px rgba(0,0,0,.1); min-height: 300px; }
+                    ul.tree { list-style: none; padding-left: 20px; margin: 2px 0; }
+                    li.node { padding: 3px 4px; border-radius: 4px; font-size: 13px; }
+                    li.node:hover { background: #eef4fb; }
+                    .toggle { display: inline-block; width: 16px; cursor: pointer; color: #888; }
+                    .icon   { margin: 0 4px; }
+                    .val    { color: #27ae60; font-family: monospace; margin-left: 6px; }
+                    .nc     { font-size: 11px; color: #aaa; margin-left: 4px; }
+                    /* NEU: Referenz-Typ Badge */
+                    .ref    { font-size: 10px; color: #fff; background: #7f8c8d;
+                              border-radius: 3px; padding: 1px 4px; margin-left: 5px; }
+                    .ref-organizes  { background: #8e44ad; } /* View → lila */
+                    .ref-component  { background: #2980b9; } /* HasComponent → blau */
+                    .ref-property   { background: #27ae60; } /* HasProperty → grün */
+                    .loading { color: #aaa; font-style: italic; }
+                    .spinner { display: inline-block; width: 14px; height: 14px; border: 2px solid #ccc;
+                               border-top-color: #3498db; border-radius: 50%;
+                               animation: spin .7s linear infinite; vertical-align: middle; }
+                    @keyframes spin { to { transform: rotate(360deg); } }
+                  </style>
+                </head>
+                <body>
+                  <h1>🔌 OPC UA Browser</h1>
+                  <div id="status-bar" class="disconnected">Verbinde…</div>
+                  <div id="toolbar">
+                    <button id="btn-root" onclick="loadRoot()">🔄 Root laden</button>
+                    <button id="btn-export" onclick="exportTwin()">⬇ Export JSON</button>
+                    <span id="twin-status"></span>
+                  </div>
+                  <div id="tree-container"><i class="loading">Warte auf Verbindung…</i></div>
+
+                  <script>
+                    async function checkStatus() {
+                      try {
+                        const d = await (await fetch('/api/status')).json();
+                        const bar = document.getElementById('status-bar');
+                        if (d.connected) {
+                          bar.className = 'connected';
+                          bar.textContent = '✅ Verbunden';
+                          loadRoot();
+                          pollTwinStatus();
+                        } else {
+                          bar.className = 'disconnected';
+                          bar.textContent = '❌ Nicht verbunden';
+                          setTimeout(checkStatus, 3000);
+                        }
+                      } catch(e) { setTimeout(checkStatus, 3000); }
+                    }
+
+                    async function pollTwinStatus() {
+                      try {
+                        const d = await (await fetch('/api/twin-status')).json();
+                        const el = document.getElementById('twin-status');
+                        if (d.ready) {
+                          el.textContent = '✅ Export bereit (' + d.nodeCount + ' Nodes)';
+                        } else if (d.building) {
+                          el.textContent = '⏳ Export wird gebaut…';
+                          setTimeout(pollTwinStatus, 3000);
+                        } else {
+                          el.textContent = '';
+                        }
+                      } catch(e) {}
+                    }
+
+                    async function loadRoot() {
+                      const container = document.getElementById('tree-container');
+                      container.innerHTML = '<span class="spinner"></span> Lade…';
+                      try {
+                        const raw = await fetch('/api/browse-tree', {
+                          method: 'POST',
+                          headers: { 'Content-Type': 'application/json' },
+                          body: '{}'
+                        });
+                        const d = await raw.json();
+                        console.log('browse-tree response:', JSON.stringify(d));
+
+                        if (!d.success) {
+                          container.innerHTML = 'API Fehler: ' + d.error;
+                          return;
+                        }
+                        if (!d.children || d.children.length === 0) {
+                          container.innerHTML = 'Keine Nodes gefunden';
+                          return;
+                        }
+
+                        container.innerHTML = 'Nodes: ' + d.children.length;
+                        container.appendChild(buildUl(d.children));
+
+                      } catch(e) {
+                        container.innerHTML = 'Exception: ' + e.message;
+                        console.error(e);
+                      }
+                    }
+
+                    async function expand(nodeId, li) {
+                      const existing = li.querySelector('ul');
+                      if (existing) {
+                        existing.style.display = existing.style.display === 'none' ? '' : 'none';
+                        li.querySelector('.toggle').textContent =
+                          existing.style.display === 'none' ? '▶' : '▼';
+                        return;
+                      }
+                      li.querySelector('.toggle').innerHTML = '<span class="spinner"></span>';
+                      try {
+                        const d = await post('/api/browse-tree', { nodeId });
+                        const ul = buildUl(d.children, nodeId);
+                        li.appendChild(ul);
+                        li.querySelector('.toggle').textContent = '▼';
+                      } catch(e) {
+                        li.querySelector('.toggle').textContent = '!';
+                      }
+                    }
+
+                    // NEU: referenceType → CSS-Klasse + Label
+                    function refBadge(refType) {
+                      if (!refType) return '';
+                      let cls = 'ref';
+                      if (refType === 'Organizes')    cls += ' ref-organizes';
+                      else if (refType === 'HasComponent') cls += ' ref-component';
+                      else if (refType === 'HasProperty')  cls += ' ref-property';
+                      const label = refType
+                        .replace('HasComponent',   'Comp')
+                        .replace('HasProperty',    'Prop')
+                        .replace('HasTypeDefinition', 'Type')
+                        .replace('Organizes',      'Org');
+                      return `<span class="${cls}">${label}</span>`;
+                    }
+
+                    function buildUl(nodes) {
+                      const ul = document.createElement('ul');
+                      ul.className = 'tree';
+                      for (const n of nodes) {
+                        const li = document.createElement('li');
+                        li.className = 'node';
+                        const isVar  = n.nodeClass === 'Variable';
+                        const isView = n.nodeClass === 'View';
+                        // NEU: View bekommt 👁-Icon
+                        const icon   = isVar ? '📊' : (isView ? '👁' : '📁');
+                        const toggle = document.createElement('span');
+                        toggle.className = 'toggle';
+                        toggle.textContent = '▶';
+                        toggle.onclick = (e) => { e.stopPropagation(); expand(n.nodeId, li); };
+                        li.appendChild(toggle);
+                        li.insertAdjacentHTML('beforeend',
+                            `<span class="icon">${icon}</span>`
+                          + `<b>${n.displayName || n.browseName}</b>`
+                          + `<span class="nc">${n.nodeClass || ''}</span>`
+                          + refBadge(n.referenceType)
+                          + (isVar && n.value != null ? `<span class="val">${n.value}</span>` : ''));
+                        ul.appendChild(li);
+                      }
+                      return ul;
+                    }
+
+                    async function post(url, body) {
+                      const r = await fetch(url, { method: 'POST',
+                        headers: { 'Content-Type': 'application/json' },
+                        body: JSON.stringify(body) });
+                      const d = await r.json();
+                      if (!d.success) throw new Error(d.error || 'Unknown error');
+                      return d;
+                    }
+
+                    function exportTwin() { window.open('/api/export', '_blank'); }
+
+                    checkStatus();
+                  </script>
+                </body>
+                </html>
+                """;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/de/opcua/app/rest/OpenApiHandler.java b/src/main/java/de/opcua/app/rest/OpenApiHandler.java
new file mode 100644
index 0000000..8f2e23c
--- /dev/null
+++ b/src/main/java/de/opcua/app/rest/OpenApiHandler.java
@@ -0,0 +1,261 @@
+package de.opcua.app.rest;
+
+import com.sun.net.httpserver.HttpExchange;
+import com.sun.net.httpserver.HttpHandler;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+/** Serves a compact OpenAPI 3.0 document for the embedded REST API. */
+public class OpenApiHandler implements HttpHandler {
+
+    @Override
+    public void handle(HttpExchange exchange) throws IOException {
+        if (!"GET".equalsIgnoreCase(exchange.getRequestMethod())
+                && !"HEAD".equalsIgnoreCase(exchange.getRequestMethod())) {
+            send(exchange, 405, "text/plain; charset=UTF-8", "GET required");
+            return;
+        }
+        String body = SPEC.replace("${BASE_URL}", baseUrl(exchange));
+        send(exchange, 200, "application/json; charset=UTF-8", body);
+    }
+
+    private static String baseUrl(HttpExchange exchange) {
+        String proto = first(exchange.getRequestHeaders().getFirst("X-Forwarded-Proto"), "http");
+        String host = first(exchange.getRequestHeaders().getFirst("Host"), "localhost:8081");
+        return proto + "://" + host;
+    }
+
+    private static String first(String value, String fallback) {
+        return value == null || value.isBlank() ? fallback : value;
+    }
+
+    private static void send(HttpExchange exchange, int code, String contentType, String body) throws IOException {
+        byte[] bytes = body.getBytes(StandardCharsets.UTF_8);
+        exchange.getResponseHeaders().set("Content-Type", contentType);
+        exchange.getResponseHeaders().set("Access-Control-Allow-Origin", "*");
+        exchange.getResponseHeaders().set("Cache-Control", "no-store");
+        exchange.sendResponseHeaders(code, "HEAD".equalsIgnoreCase(exchange.getRequestMethod()) ? -1 : bytes.length);
+        if (!"HEAD".equalsIgnoreCase(exchange.getRequestMethod())) {
+            try (var os = exchange.getResponseBody()) {
+                os.write(bytes);
+            }
+        }
+    }
+
+    private static final String SPEC = """
+{
+  "openapi": "3.0.3",
+  "info": {
+    "title": "OPC UA Client REST API",
+    "version": "1.0.0",
+    "description": "Embedded REST API for browsing, reading, writing, exporting OPC UA nodes and managing GraalVM JavaScript actions."
+  },
+  "servers": [
+    { "url": "${BASE_URL}", "description": "Current embedded HTTP server" }
+  ],
+  "tags": [
+    { "name": "Status" },
+    { "name": "OPC UA" },
+    { "name": "Digital Twin" },
+    { "name": "Actions" },
+    { "name": "Documentation" }
+  ],
+  "paths": {
+    "/api/status": {
+      "get": {
+        "tags": ["Status"],
+        "summary": "Return OPC UA connection status",
+        "responses": { "200": { "description": "Status", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/StatusResponse" } } } } }
+      }
+    },
+    "/api/health": {
+      "get": {
+        "tags": ["Status"],
+        "summary": "Return HTTP service health",
+        "responses": { "200": { "description": "Health", "content": { "application/json": { "schema": { "type": "object", "properties": { "status": { "type": "string", "example": "ok" } } } } } } }
+      }
+    },
+    "/api/read": {
+      "post": {
+        "tags": ["OPC UA"],
+        "summary": "Read a value from an OPC UA node",
+        "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/NodeReadRequest" } } } },
+        "responses": { "200": { "description": "Read result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/NodeReadResponse" } } } }, "503": { "$ref": "#/components/responses/NotConnected" } }
+      }
+    },
+    "/api/write": {
+      "post": {
+        "tags": ["OPC UA"],
+        "summary": "Write a value to an OPC UA node",
+        "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/NodeWriteRequest" } } } },
+        "responses": { "200": { "description": "Write result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/NodeWriteResponse" } } } }, "503": { "$ref": "#/components/responses/NotConnected" } }
+      }
+    },
+    "/api/browse": {
+      "post": {
+        "tags": ["OPC UA"],
+        "summary": "Browse one node level",
+        "requestBody": { "required": false, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/BrowseRequest" } } } },
+        "responses": { "200": { "description": "Browse result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/BrowseResponse" } } } }, "503": { "$ref": "#/components/responses/NotConnected" } }
+      }
+    },
+    "/api/browse-tree": {
+      "post": {
+        "tags": ["OPC UA"],
+        "summary": "Browse one node level for the lazy web tree, including variable values",
+        "requestBody": { "required": false, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/BrowseRequest" } } } },
+        "responses": { "200": { "description": "Browse-tree result", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/BrowseResponse" } } } }, "503": { "$ref": "#/components/responses/NotConnected" } }
+      }
+    },
+    "/api/twin-status": {
+      "get": {
+        "tags": ["Digital Twin"],
+        "summary": "Return recursive export cache status",
+        "responses": { "200": { "description": "Twin build status", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/TwinStatusResponse" } } } } }
+      }
+    },
+    "/api/export": {
+      "get": {
+        "tags": ["Digital Twin"],
+        "summary": "Download the complete cached OPC UA tree as JSON",
+        "responses": { "200": { "description": "Full export", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ExportResponse" } } } }, "202": { "description": "Export cache is still building" }, "503": { "$ref": "#/components/responses/NotConnected" } }
+      }
+    },
+    "/api/actions": {
+      "get": {
+        "tags": ["Actions"],
+        "summary": "List all configured node actions",
+        "responses": { "200": { "description": "Actions", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ActionListResponse" } } } } }
+      },
+      "post": {
+        "tags": ["Actions"],
+        "summary": "Create a GraalVM JavaScript action",
+        "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Action" } } } },
+        "responses": { "200": { "description": "Created action", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ActionResponse" } } } } }
+      }
+    },
+    "/api/actions/delete": {
+      "post": {
+        "tags": ["Actions"],
+        "summary": "Delete an action by nodeId and name",
+        "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ActionKey" } } } },
+        "responses": { "200": { "$ref": "#/components/responses/Success" } }
+      }
+    },
+    "/api/actions/enable": {
+      "post": {
+        "tags": ["Actions"],
+        "summary": "Enable or disable an action",
+        "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ActionEnableRequest" } } } },
+        "responses": { "200": { "$ref": "#/components/responses/Success" } }
+      }
+    },
+    "/api/actions/test": {
+      "post": {
+        "tags": ["Actions"],
+        "summary": "Queue a manual test run of an action",
+        "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ActionTestRequest" } } } },
+        "responses": { "200": { "description": "Queued", "content": { "application/json": { "schema": { "type": "object", "properties": { "success": { "type": "boolean" }, "queued": { "type": "boolean" } } } } } } }
+      }
+    },
+    "/help": {
+      "get": { "tags": ["Documentation"], "summary": "Swagger-like HTML documentation", "responses": { "200": { "description": "HTML help" } } }
+    },
+    "/api/openapi.json": {
+      "get": { "tags": ["Documentation"], "summary": "OpenAPI 3.0 JSON document", "responses": { "200": { "description": "OpenAPI JSON" } } }
+    }
+  },
+  "components": {
+    "responses": {
+      "Success": { "description": "Success response", "content": { "application/json": { "schema": { "type": "object", "properties": { "success": { "type": "boolean" } } } } } },
+      "NotConnected": { "description": "OPC UA server is not connected", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } }
+    },
+    "schemas": {
+      "StatusResponse": {
+        "type": "object",
+        "properties": { "connected": { "type": "boolean" }, "timestamp": { "type": "integer", "format": "int64" } }
+      },
+      "ErrorResponse": {
+        "type": "object",
+        "properties": { "success": { "type": "boolean", "example": false }, "error": { "type": "string" } }
+      },
+      "NodeReadRequest": {
+        "type": "object",
+        "required": ["nodeId"],
+        "properties": { "nodeId": { "type": "string", "example": "ns=3;s=AirConditioner_1.Temperature" } }
+      },
+      "NodeReadResponse": {
+        "type": "object",
+        "properties": { "success": { "type": "boolean" }, "nodeId": { "type": "string" }, "value": { "type": "string" }, "timestamp": { "type": "integer", "format": "int64" } }
+      },
+      "NodeWriteRequest": {
+        "type": "object",
+        "required": ["nodeId", "value"],
+        "properties": { "nodeId": { "type": "string" }, "value": { "description": "Value as string, number or boolean", "nullable": false } }
+      },
+      "NodeWriteResponse": {
+        "type": "object",
+        "properties": { "success": { "type": "boolean" }, "nodeId": { "type": "string" }, "written": { "type": "boolean" } }
+      },
+      "BrowseRequest": {
+        "type": "object",
+        "properties": { "nodeId": { "type": "string", "nullable": true, "description": "Omit or null for root" } }
+      },
+      "BrowseNode": {
+        "type": "object",
+        "properties": {
+          "nodeId": { "type": "string" },
+          "displayName": { "type": "string" },
+          "browseName": { "type": "string" },
+          "nodeClass": { "type": "string" },
+          "referenceType": { "type": "string" },
+          "dataType": { "type": "string" },
+          "accessLevel": { "type": "string" },
+          "value": { "type": "string", "nullable": true },
+          "hasChildren": { "type": "boolean", "nullable": true }
+        }
+      },
+      "BrowseResponse": {
+        "type": "object",
+        "properties": { "success": { "type": "boolean" }, "children": { "type": "array", "items": { "$ref": "#/components/schemas/BrowseNode" } } }
+      },
+      "TwinStatusResponse": {
+        "type": "object",
+        "properties": { "ready": { "type": "boolean" }, "building": { "type": "boolean" }, "cacheTime": { "type": "integer", "format": "int64" }, "nodeCount": { "type": "integer" } }
+      },
+      "ExportResponse": {
+        "type": "object",
+        "properties": { "timestamp": { "type": "integer", "format": "int64" }, "exportType": { "type": "string" }, "nodeCount": { "type": "integer" }, "tree": { "type": "array", "items": { "$ref": "#/components/schemas/ExportNode" } } }
+      },
+      "ExportNode": {
+        "allOf": [ { "$ref": "#/components/schemas/BrowseNode" }, { "type": "object", "properties": { "children": { "type": "array", "items": { "$ref": "#/components/schemas/ExportNode" } }, "cycle": { "type": "boolean", "nullable": true } } } ]
+      },
+      "Action": {
+        "type": "object",
+        "required": ["nodeId", "name", "script"],
+        "properties": {
+          "nodeId": { "type": "string" },
+          "name": { "type": "string", "description": "Alias: actionName" },
+          "actionName": { "type": "string" },
+          "triggerType": { "type": "string", "enum": ["ON_CHANGE", "ON_EVEN", "ON_ODD", "ON_TRUE", "ON_FALSE", "ON_VALUE", "ON_GREATER_THAN", "ON_LESS_THAN", "ON_INTERVAL"] },
+          "triggerValue": { "type": "string", "nullable": true },
+          "intervalMs": { "type": "integer", "example": 1000 },
+          "enabled": { "type": "boolean" },
+          "conditionEnabled": { "type": "boolean" },
+          "conditionScript": { "type": "string", "nullable": true },
+          "conditionNodeIds": { "type": "array", "items": { "type": "string" } },
+          "nodeAliases": { "type": "object", "additionalProperties": { "type": "string" } },
+          "script": { "type": "string" }
+        }
+      },
+      "ActionResponse": { "type": "object", "properties": { "success": { "type": "boolean" }, "action": { "$ref": "#/components/schemas/Action" } } },
+      "ActionListResponse": { "type": "object", "properties": { "success": { "type": "boolean" }, "actions": { "type": "array", "items": { "$ref": "#/components/schemas/Action" } } } },
+      "ActionKey": { "type": "object", "required": ["nodeId", "name"], "properties": { "nodeId": { "type": "string" }, "name": { "type": "string" }, "actionName": { "type": "string" } } },
+      "ActionEnableRequest": { "allOf": [ { "$ref": "#/components/schemas/ActionKey" }, { "type": "object", "properties": { "enabled": { "type": "boolean" } } } ] },
+      "ActionTestRequest": { "allOf": [ { "$ref": "#/components/schemas/ActionKey" }, { "type": "object", "properties": { "value": { "type": "string" } } } ] }
+    }
+  }
+}
+""";
+}
diff --git a/src/main/java/de/opcua/app/scripting/GraalScriptEngine.java b/src/main/java/de/opcua/app/scripting/GraalScriptEngine.java
new file mode 100644
index 0000000..f6fc802
--- /dev/null
+++ b/src/main/java/de/opcua/app/scripting/GraalScriptEngine.java
@@ -0,0 +1,628 @@
+package de.opcua.app.scripting;
+
+import de.opcua.app.opc.OpcUaService;
+import org.graalvm.polyglot.Context;
+import org.graalvm.polyglot.HostAccess;
+import org.graalvm.polyglot.Value;
+import org.graalvm.polyglot.proxy.ProxyArray;
+import org.graalvm.polyglot.proxy.ProxyExecutable;
+import org.graalvm.polyglot.proxy.ProxyObject;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * GraalVM-based JavaScript engine.
+ *
+ * Important: GraalVM Context is not thread-safe. Therefore every event/script
+ * execution receives its own isolated Context. This allows parallel execution
+ * where every OPC-UA event/action can run in its own thread without overwriting
+ * global JavaScript variables from another event.
+ */
+public class GraalScriptEngine {
+
+    private final OpcUaService opcService;
+    private final Store store;
+    private final RestClient restClient;
+    private final Map<String, Object> globalBindings;
+    private final SharedScope globalScope;
+    private final Map<String, SharedScope> sessionScopes;
+    private volatile boolean availabilityChecked = false;
+    private volatile boolean available = false;
+
+    public GraalScriptEngine(OpcUaService opcService, Store store) {
+        this.opcService = opcService;
+        this.store = store;
+        this.restClient = new RestClient();
+        this.globalBindings = new ConcurrentHashMap<>();
+        this.globalScope = new SharedScope();
+        this.sessionScopes = new ConcurrentHashMap<>();
+    }
+
+    private Context createContext() {
+        Context context = Context.newBuilder("js")
+                .allowHostAccess(HostAccess.ALL)
+                .allowIO(true)
+                .option("js.ecmascript-version", "2022")
+                .build();
+        initializeContext(context);
+        return context;
+    }
+
+    private void initializeContext(Context context) {
+        var bindings = context.getBindings("js");
+
+        bindings.putMember("opc", new OpcUaFacade(opcService));
+        bindings.putMember("rest", restClient);
+        bindings.putMember("http", restClient); // alias for intuitive JavaScript examples
+        bindings.putMember("store", store);
+        bindings.putMember("global", globalScope);
+        bindings.putMember("globals", globalScope);
+        bindings.putMember("console", new Console());
+        bindings.putMember("log", new Log());
+        bindings.putMember("sleep", new SleepFunction());
+
+        for (Map.Entry<String, Object> entry : globalBindings.entrySet()) {
+            bindings.putMember(entry.getKey(), entry.getValue());
+        }
+    }
+
+    public boolean isAvailable() {
+        if (availabilityChecked) return available;
+        synchronized (this) {
+            if (availabilityChecked) return available;
+            try (Context ignored = createContext()) {
+                available = true;
+                System.out.println("[GraalVM] JavaScript engine ready");
+            } catch (Exception e) {
+                available = false;
+                System.err.println("[GraalVM] Failed to initialize: " + e.getMessage());
+                System.err.println("[GraalVM] Make sure GraalVM JS dependencies are on the classpath.");
+            } finally {
+                availabilityChecked = true;
+            }
+            return available;
+        }
+    }
+
+    /** Execute JavaScript code without extra per-event bindings. */
+    public Object execute(String script) {
+        return execute(script, Map.of());
+    }
+
+    /** Execute JavaScript code with event-specific bindings. */
+    public Object execute(String script, Map<String, Object> bindings) {
+        if (!isAvailable()) {
+            throw new ScriptExecutionException(
+                    "GraalVM JavaScript engine not available. Make sure graalvm-js dependencies are on classpath.",
+                    null
+            );
+        }
+
+        try (Context context = createContext()) {
+            putBindings(context, bindings);
+            Value result = context.eval("js", script == null ? "" : script);
+            return convertValueToJava(result);
+        } catch (Exception e) {
+            throw new ScriptExecutionException("Script execution failed", e);
+        }
+    }
+
+    /** Evaluate a JavaScript condition and convert the result to boolean semantics. */
+    public boolean executeCondition(String conditionScript, Map<String, Object> bindings) {
+        Object result = execute(conditionScript, bindings);
+        return toBoolean(result);
+    }
+
+    /** Execute script asynchronously. */
+    public CompletableFuture<Object> executeAsync(String script) {
+        return CompletableFuture.supplyAsync(() -> execute(script));
+    }
+
+    public CompletableFuture<Object> executeAsync(String script, Map<String, Object> bindings) {
+        return CompletableFuture.supplyAsync(() -> execute(script, bindings));
+    }
+
+    /** Bind a Java object as a global default for all future event contexts. */
+    public void bind(String name, Object value) {
+        if (name == null || name.isBlank()) return;
+        globalBindings.put(name, value);
+    }
+
+    /** Get a global binding. Event-local bindings are intentionally not retained. */
+    public Object get(String name) {
+        Object value = globalScope.get(name);
+        return value != null ? value : globalBindings.get(name);
+    }
+
+    /** Shared, writable JavaScript object for all actions. Example: global.token = "abc". */
+    public SharedScope getGlobalScope() {
+        return globalScope;
+    }
+
+    /** Shared, writable JavaScript object for one action/session. */
+    public SharedScope getSessionScope(String key) {
+        String safeKey = key == null || key.isBlank() ? "default" : key;
+        return sessionScopes.computeIfAbsent(safeKey, ignored -> new SharedScope());
+    }
+
+    public void resetSessionScope(String key) {
+        if (key != null) sessionScopes.remove(key);
+    }
+
+    private void putBindings(Context context, Map<String, Object> bindings) {
+        if (bindings == null) return;
+        var jsBindings = context.getBindings("js");
+        for (Map.Entry<String, Object> entry : bindings.entrySet()) {
+            String key = entry.getKey();
+            if (key == null || key.isBlank()) continue;
+            jsBindings.putMember(key, entry.getValue());
+        }
+    }
+
+    private Object convertValueToJava(Value value) {
+        if (value == null || value.isNull()) return null;
+        if (value.isBoolean()) return value.asBoolean();
+        if (value.isNumber()) {
+            if (value.fitsInInt()) return value.asInt();
+            if (value.fitsInLong()) return value.asLong();
+            return value.asDouble();
+        }
+        if (value.isString()) return value.asString();
+        if (value.hasArrayElements()) {
+            long size = value.getArraySize();
+            List<Object> array = new ArrayList<>((int) size);
+            for (int i = 0; i < size; i++) {
+                array.add(convertValueToJava(value.getArrayElement(i)));
+            }
+            return array;
+        }
+        if (value.hasMembers() && !value.isHostObject()) {
+            Map<String, Object> object = new LinkedHashMap<>();
+            for (String key : value.getMemberKeys()) {
+                object.put(key, convertValueToJava(value.getMember(key)));
+            }
+            return object;
+        }
+        if (value.isHostObject()) return value.asHostObject();
+        return value.toString();
+    }
+
+    private boolean toBoolean(Object result) {
+        if (result == null) return false;
+        if (result instanceof Boolean b) return b;
+        if (result instanceof Number n) return n.doubleValue() != 0.0d;
+        String s = result.toString().trim();
+        if (s.isEmpty()) return false;
+        if ("true".equalsIgnoreCase(s)) return true;
+        if ("false".equalsIgnoreCase(s)) return false;
+        try {
+            return Double.parseDouble(s) != 0.0d;
+        } catch (NumberFormatException ignored) {
+            return true;
+        }
+    }
+
+    public void close() {
+        globalBindings.clear();
+        globalScope.clear();
+        sessionScopes.clear();
+    }
+
+    /**
+     * Thread-safe JavaScript-visible object used for global/session state.
+     * It supports both property access and methods:
+     *
+     *   global.token = "abc";
+     *   var token = global.token;
+     *   global.set("apiResult", JSON.parse(response.body));
+     *   var result = global.get("apiResult");
+     */
+    public static class SharedScope implements ProxyObject {
+        private final Map<String, Object> values = new ConcurrentHashMap<>();
+
+        public Object get(String key) {
+            return values.get(key);
+        }
+
+        public void set(String key, Object value) {
+            if (key == null || key.isBlank()) return;
+            Object normalized = normalize(value);
+            if (normalized == null) values.remove(key);
+            else values.put(key, normalized);
+        }
+
+        public boolean contains(String key) {
+            return key != null && values.containsKey(key);
+        }
+
+        public Object remove(String key) {
+            return key == null ? null : values.remove(key);
+        }
+
+        public void clear() {
+            values.clear();
+        }
+
+        public Map<String, Object> snapshot() {
+            return Map.copyOf(values);
+        }
+
+        @Override
+        public Object getMember(String key) {
+            return switch (key) {
+                case "get" -> (ProxyExecutable) args -> args.length > 0 ? toGuest(get(keyOf(args[0]))) : null;
+                case "set" -> (ProxyExecutable) args -> {
+                    if (args.length > 0) set(keyOf(args[0]), args.length > 1 ? args[1] : null);
+                    return null;
+                };
+                case "contains", "has" -> (ProxyExecutable) args -> args.length > 0 && contains(keyOf(args[0]));
+                case "remove", "delete" -> (ProxyExecutable) args -> args.length > 0 ? remove(keyOf(args[0])) : null;
+                case "clear" -> (ProxyExecutable) args -> { clear(); return null; };
+                case "snapshot" -> (ProxyExecutable) args -> snapshot();
+                default -> toGuest(values.get(key));
+            };
+        }
+
+        @Override
+        public Object getMemberKeys() {
+            return values.keySet().toArray(new String[0]);
+        }
+
+        @Override
+        public boolean hasMember(String key) {
+            return values.containsKey(key) ||
+                    "get".equals(key) || "set".equals(key) || "contains".equals(key) ||
+                    "has".equals(key) || "remove".equals(key) || "delete".equals(key) ||
+                    "clear".equals(key) || "snapshot".equals(key);
+        }
+
+        @Override
+        public void putMember(String key, Value value) {
+            set(key, value);
+        }
+
+        private static String keyOf(Object value) {
+            if (value instanceof Value v && v.isString()) return v.asString();
+            return String.valueOf(value);
+        }
+
+        private static Object toGuest(Object value) {
+            if (value instanceof Map<?, ?> map) {
+                Map<String, Object> guestMap = new LinkedHashMap<>();
+                for (Map.Entry<?, ?> entry : map.entrySet()) {
+                    if (entry.getKey() != null) {
+                        guestMap.put(String.valueOf(entry.getKey()), toGuest(entry.getValue()));
+                    }
+                }
+                return ProxyObject.fromMap(guestMap);
+            }
+            if (value instanceof List<?> list) {
+                List<Object> guestList = new ArrayList<>(list.size());
+                for (Object item : list) guestList.add(toGuest(item));
+                return ProxyArray.fromArray(guestList.toArray(new Object[0]));
+            }
+            if (value instanceof Object[] array) {
+                List<Object> guestList = new ArrayList<>(array.length);
+                for (Object item : array) guestList.add(toGuest(item));
+                return ProxyArray.fromArray(guestList.toArray(new Object[0]));
+            }
+            return value;
+        }
+
+        private static Object normalize(Object value) {
+            if (value == null) return null;
+            if (value instanceof Value v) return convertGraalValue(v);
+            return value;
+        }
+
+        private static Object convertGraalValue(Value value) {
+            if (value == null || value.isNull()) return null;
+            if (value.isBoolean()) return value.asBoolean();
+            if (value.isNumber()) {
+                if (value.fitsInInt()) return value.asInt();
+                if (value.fitsInLong()) return value.asLong();
+                return value.asDouble();
+            }
+            if (value.isString()) return value.asString();
+            if (value.hasArrayElements()) {
+                long size = value.getArraySize();
+                List<Object> list = new ArrayList<>((int) size);
+                for (long i = 0; i < size; i++) list.add(convertGraalValue(value.getArrayElement(i)));
+                return list;
+            }
+            if (value.hasMembers() && !value.isHostObject()) {
+                Map<String, Object> map = new LinkedHashMap<>();
+                for (String key : value.getMemberKeys()) map.put(key, convertGraalValue(value.getMember(key)));
+                return map;
+            }
+            if (value.isHostObject()) return value.asHostObject();
+            return value.toString();
+        }
+    }
+
+    public static class OpcUaFacade {
+        private final OpcUaService opcService;
+
+        public OpcUaFacade(OpcUaService opcService) {
+            this.opcService = opcService;
+        }
+
+        public String read(String nodeId) {
+            try {
+                return opcService.readValue(nodeId).get();
+            } catch (Exception e) {
+                throw new RuntimeException("Failed to read node: " + nodeId, e);
+            }
+        }
+
+        public boolean write(String nodeId, Object value) {
+            try {
+                return opcService.writeValue(nodeId, value).get();
+            } catch (Exception e) {
+                throw new RuntimeException("Failed to write node: " + nodeId, e);
+            }
+        }
+
+        public Map<String, String> readMultiple(String[] nodeIds) {
+            Map<String, String> results = new HashMap<>();
+            if (nodeIds == null) return results;
+            for (String nodeId : nodeIds) {
+                try {
+                    results.put(nodeId, read(nodeId));
+                } catch (Exception e) {
+                    results.put(nodeId, "<error: " + e.getMessage() + ">");
+                }
+            }
+            return results;
+        }
+
+        public Map<String, String> readMultiple(List<String> nodeIds) {
+            Map<String, String> results = new HashMap<>();
+            if (nodeIds == null) return results;
+            for (String nodeId : nodeIds) {
+                try {
+                    results.put(nodeId, read(nodeId));
+                } catch (Exception e) {
+                    results.put(nodeId, "<error: " + e.getMessage() + ">");
+                }
+            }
+            return results;
+        }
+
+        public boolean writeMultiple(Map<String, Object> valuesByNodeId) {
+            if (valuesByNodeId == null) return true;
+            boolean ok = true;
+            for (Map.Entry<String, Object> entry : valuesByNodeId.entrySet()) {
+                ok &= write(entry.getKey(), entry.getValue());
+            }
+            return ok;
+        }
+
+        public boolean isConnected() {
+            return opcService.isConnected();
+        }
+    }
+
+    public static class RestClient {
+        private static final ObjectMapper MAPPER = new ObjectMapper();
+        private final HttpClient httpClient;
+
+        public RestClient() {
+            this.httpClient = HttpClient.newBuilder()
+                    .connectTimeout(Duration.ofSeconds(10))
+                    .build();
+        }
+
+        public RestResponse get(String url) { return get(url, null); }
+
+        public RestResponse get(String url, Map<String, String> headers) {
+            try {
+                HttpRequest.Builder builder = HttpRequest.newBuilder().uri(URI.create(url)).GET();
+                if (headers != null) headers.forEach(builder::header);
+                HttpResponse<String> response = httpClient.send(builder.build(), HttpResponse.BodyHandlers.ofString());
+                return new RestResponse(response.statusCode(), response.body(), response.headers().map());
+            } catch (Exception e) {
+                throw new RuntimeException("GET request failed: " + url, e);
+            }
+        }
+
+        public RestResponse post(String url, String body) { return post(url, body, null); }
+
+        public RestResponse postJson(String url, Object body) {
+            return post(url, toJson(body), Map.of("Content-Type", "application/json"));
+        }
+
+        public RestResponse postJson(String url, Object body, Map<String, String> headers) {
+            Map<String, String> mergedHeaders = new HashMap<>();
+            mergedHeaders.put("Content-Type", "application/json");
+            if (headers != null) mergedHeaders.putAll(headers);
+            return post(url, toJson(body), mergedHeaders);
+        }
+
+        public RestResponse post(String url, String body, Map<String, String> headers) {
+            try {
+                HttpRequest.Builder builder = HttpRequest.newBuilder()
+                        .uri(URI.create(url))
+                        .POST(HttpRequest.BodyPublishers.ofString(body == null ? "" : body))
+                        .header("Content-Type", "application/json");
+                if (headers != null) headers.forEach(builder::header);
+                HttpResponse<String> response = httpClient.send(builder.build(), HttpResponse.BodyHandlers.ofString());
+                return new RestResponse(response.statusCode(), response.body(), response.headers().map());
+            } catch (Exception e) {
+                throw new RuntimeException("POST request failed: " + url, e);
+            }
+        }
+
+        public RestResponse put(String url, String body) { return put(url, body, null); }
+
+        public RestResponse putJson(String url, Object body) {
+            return put(url, toJson(body), Map.of("Content-Type", "application/json"));
+        }
+
+        public RestResponse putJson(String url, Object body, Map<String, String> headers) {
+            Map<String, String> mergedHeaders = new HashMap<>();
+            mergedHeaders.put("Content-Type", "application/json");
+            if (headers != null) mergedHeaders.putAll(headers);
+            return put(url, toJson(body), mergedHeaders);
+        }
+
+        public RestResponse put(String url, String body, Map<String, String> headers) {
+            try {
+                HttpRequest.Builder builder = HttpRequest.newBuilder()
+                        .uri(URI.create(url))
+                        .PUT(HttpRequest.BodyPublishers.ofString(body == null ? "" : body))
+                        .header("Content-Type", "application/json");
+                if (headers != null) headers.forEach(builder::header);
+                HttpResponse<String> response = httpClient.send(builder.build(), HttpResponse.BodyHandlers.ofString());
+                return new RestResponse(response.statusCode(), response.body(), response.headers().map());
+            } catch (Exception e) {
+                throw new RuntimeException("PUT request failed: " + url, e);
+            }
+        }
+
+        private String toJson(Object body) {
+            if (body == null) return "null";
+            if (body instanceof String s) return s;
+            if (body instanceof Value v) {
+                if (v.isNull()) return "null";
+                if (v.isString()) return quote(v.asString());
+                if (v.isBoolean() || v.isNumber()) return v.toString();
+                if (v.hasArrayElements()) {
+                    StringBuilder sb = new StringBuilder("[");
+                    for (long i = 0; i < v.getArraySize(); i++) {
+                        if (i > 0) sb.append(',');
+                        sb.append(toJson(v.getArrayElement(i)));
+                    }
+                    return sb.append(']').toString();
+                }
+                if (v.hasMembers()) {
+                    StringBuilder sb = new StringBuilder("{");
+                    boolean first = true;
+                    for (String key : v.getMemberKeys()) {
+                        if (!first) sb.append(',');
+                        first = false;
+                        sb.append(quote(key)).append(':').append(toJson(v.getMember(key)));
+                    }
+                    return sb.append('}').toString();
+                }
+                return quote(v.toString());
+            }
+            try {
+                return MAPPER.writeValueAsString(body);
+            } catch (Exception e) {
+                return quote(String.valueOf(body));
+            }
+        }
+
+        private String quote(String s) {
+            try {
+                return MAPPER.writeValueAsString(s == null ? "" : s);
+            } catch (Exception e) {
+                return "\"" + String.valueOf(s).replace("\\", "\\\\").replace("\"", "\\\"") + "\"";
+            }
+        }
+
+        public RestResponse delete(String url) { return delete(url, null); }
+
+        public RestResponse delete(String url, Map<String, String> headers) {
+            try {
+                HttpRequest.Builder builder = HttpRequest.newBuilder().uri(URI.create(url)).DELETE();
+                if (headers != null) headers.forEach(builder::header);
+                HttpResponse<String> response = httpClient.send(builder.build(), HttpResponse.BodyHandlers.ofString());
+                return new RestResponse(response.statusCode(), response.body(), response.headers().map());
+            } catch (Exception e) {
+                throw new RuntimeException("DELETE request failed: " + url, e);
+            }
+        }
+    }
+
+    public static class RestResponse {
+        private final int status;
+        private final String body;
+        private final Map<String, java.util.List<String>> headers;
+
+        public RestResponse(int status, String body, Map<String, java.util.List<String>> headers) {
+            this.status = status;
+            this.body = body;
+            this.headers = headers;
+        }
+
+        public int getStatus() { return status; }
+        public String getBody() { return body; }
+        public Map<String, java.util.List<String>> getHeaders() { return headers; }
+        public String json() { return body; }
+        public boolean isOk() { return status >= 200 && status < 300; }
+    }
+
+    public static class Console {
+        public void log(Object... messages) {
+            StringBuilder sb = new StringBuilder("[JS] ");
+            for (Object msg : messages) sb.append(msg).append(" ");
+            System.out.println(sb.toString().trim());
+        }
+
+        public void error(Object... messages) {
+            StringBuilder sb = new StringBuilder("[JS ERROR] ");
+            for (Object msg : messages) sb.append(msg).append(" ");
+            System.err.println(sb.toString().trim());
+        }
+
+        public void warn(Object... messages) {
+            StringBuilder sb = new StringBuilder("[JS WARN] ");
+            for (Object msg : messages) sb.append(msg).append(" ");
+            System.out.println(sb.toString().trim());
+        }
+    }
+
+
+    public static class Log {
+        public void info(Object... messages) {
+            print("[JS INFO]", messages, false);
+        }
+
+        public void warn(Object... messages) {
+            print("[JS WARN]", messages, false);
+        }
+
+        public void error(Object... messages) {
+            print("[JS ERROR]", messages, true);
+        }
+
+        private void print(String prefix, Object[] messages, boolean stderr) {
+            StringBuilder sb = new StringBuilder(prefix).append(' ');
+            if (messages != null) {
+                for (Object msg : messages) sb.append(msg).append(' ');
+            }
+            String line = sb.toString().trim();
+            if (stderr) System.err.println(line); else System.out.println(line);
+        }
+    }
+
+    public static class SleepFunction {
+        public void sleep(long milliseconds) {
+            try {
+                Thread.sleep(milliseconds);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        }
+    }
+
+    public static class ScriptExecutionException extends RuntimeException {
+        public ScriptExecutionException(String message, Throwable cause) {
+            super(message, cause);
+        }
+    }
+}
diff --git a/src/main/java/de/opcua/app/scripting/ScriptService.java b/src/main/java/de/opcua/app/scripting/ScriptService.java
new file mode 100644
index 0000000..095d3b9
--- /dev/null
+++ b/src/main/java/de/opcua/app/scripting/ScriptService.java
@@ -0,0 +1,29 @@
+package de.opcua.app.scripting;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ScriptService {
+
+    private final Map<String, Object> bindings = new HashMap<>();
+
+    public ScriptService() {
+        // aktuell kein JS-Engine vorhanden
+    }
+
+    /** Gibt an, ob Scripting verfügbar ist */
+    public boolean isAvailable() {
+        return false; // bewusst deaktiviert
+    }
+
+    /** Platzhalter für spätere Engine */
+    public Object eval(String code) {
+        throw new UnsupportedOperationException(
+                "Scripting ist deaktiviert (keine JS-Engine vorhanden)");
+    }
+
+    /** Bindings registrieren (werden aktuell ignoriert) */
+    public void put(String name, Object value) {
+        bindings.put(name, value);
+    }
+}
diff --git a/src/main/java/de/opcua/app/scripting/ScriptSnippetBuilder.java b/src/main/java/de/opcua/app/scripting/ScriptSnippetBuilder.java
new file mode 100644
index 0000000..4b2e4ac
--- /dev/null
+++ b/src/main/java/de/opcua/app/scripting/ScriptSnippetBuilder.java
@@ -0,0 +1,294 @@
+package de.opcua.app.scripting;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Generates copyable JavaScript snippets with fixed NodeIds.
+ *
+ * The UI may use selected rows as a convenience, but the generated script must
+ * never depend on runtime checkbox state. Therefore every generated line contains
+ * the full NodeId literal, e.g. var Temperatur = Number(opc.read("ns=..."));
+ */
+public final class ScriptSnippetBuilder {
+    private ScriptSnippetBuilder() {}
+
+    public record NodeSpec(String nodeId, String alias) {}
+
+    public static String build(String mode, List<NodeSpec> nodes, String writeExpression) {
+        String normalizedMode = mode == null ? "readNumber" : mode.trim().toLowerCase(Locale.ROOT);
+        String expression = writeExpression == null || writeExpression.isBlank() ? "/* Wert */" : writeExpression.trim();
+        List<NodeSpec> safeNodes = nodes == null ? List.<NodeSpec>of() : nodes;
+
+        switch (normalizedMode) {
+            case "templateget", "gettemplate", "restget", "get" -> { return restGetTemplate(safeNodes); }
+            case "templatepost", "posttemplate", "restpost", "post" -> { return restPostTemplate(safeNodes); }
+            case "templateset", "settemplate", "set", "opcset" -> { return opcSetTemplate(safeNodes); }
+            default -> { }
+        }
+
+        StringBuilder sb = new StringBuilder();
+        for (NodeSpec node : safeNodes) {
+            if (node == null || node.nodeId() == null || node.nodeId().isBlank()) continue;
+            String alias = safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+            switch (normalizedMode) {
+                case "read", "readstring", "string" -> sb.append(read(node.nodeId(), alias, false));
+                case "write" -> sb.append(write(node.nodeId(), expression));
+                case "readwrite", "read-write" -> {
+                    sb.append(read(node.nodeId(), alias, true));
+                    sb.append(write(node.nodeId(), alias));
+                }
+                case "readnumber", "number", "read_number" -> sb.append(read(node.nodeId(), alias, true));
+                default -> sb.append(read(node.nodeId(), alias, true));
+            }
+        }
+        return sb.toString();
+    }
+
+
+    public static String restGetTemplate(List<NodeSpec> nodes) {
+        List<NodeSpec> safeNodes = nodes == null ? List.of() : nodes;
+        StringBuilder sb = new StringBuilder();
+        sb.append("// GET Template: OPC-UA Werte lesen, REST GET aufrufen, Ergebnis global merken und optional per opc.write schreiben\n");
+        appendReadVariables(sb, safeNodes);
+        sb.append("\nvar url = \"http://localhost:9000/api/process\"");
+        if (!safeNodes.isEmpty()) {
+            boolean first = true;
+            for (NodeSpec node : safeNodes) {
+                if (node == null || node.nodeId() == null || node.nodeId().isBlank()) continue;
+                String alias = safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+                sb.append(first ? "\n  + \"?" : "\n  + \"&");
+                sb.append(alias).append("=\" + encodeURIComponent(String(").append(alias).append("))");
+                first = false;
+            }
+            sb.append(";\n");
+        } else {
+            sb.append(";\n");
+        }
+        sb.append("\nvar response = http.get(url, {\n");
+        sb.append("  Authorization: \"Bearer \" + (global.session && global.session.token ? global.session.token : \"\")\n");
+        sb.append("});\n\n");
+        appendResponseHandling(sb);
+        sb.append("\n// Ergebnis in OPC-UA schreiben, NodeID anpassen:\n");
+        sb.append("// opc.write(\"ns=3;s=AirConditioner_1.ResultValue\", result.value);\n");
+        return sb.toString();
+    }
+
+    public static String restPostTemplate(List<NodeSpec> nodes) {
+        List<NodeSpec> safeNodes = nodes == null ? List.of() : nodes;
+        StringBuilder sb = new StringBuilder();
+        sb.append("// POST Template: OPC-UA Werte lesen, REST POST senden, Ergebnis global merken und per opc.write schreiben\n");
+        appendReadVariables(sb, safeNodes);
+        sb.append("\nvar payload = {\n");
+        for (NodeSpec node : safeNodes) {
+            if (node == null || node.nodeId() == null || node.nodeId().isBlank()) continue;
+            String alias = safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+            sb.append("  ").append(alias).append(": ").append(alias).append(",\n");
+        }
+        sb.append("  eventNode: event.nodeId,\n");
+        sb.append("  eventValue: currentValue,\n");
+        sb.append("  timestamp: new Date().toISOString()\n");
+        sb.append("};\n\n");
+        sb.append("var response = http.postJson(\"http://localhost:9000/api/process\", payload, {\n");
+        sb.append("  Authorization: \"Bearer \" + (global.session && global.session.token ? global.session.token : \"\")\n");
+        sb.append("});\n\n");
+        appendResponseHandling(sb);
+        sb.append("\n// Ergebnis in OPC-UA schreiben, NodeID anpassen:\n");
+        sb.append("// opc.write(\"ns=3;s=AirConditioner_1.ResultValue\", result.value);\n");
+        return sb.toString();
+    }
+
+    public static String opcSetTemplate(List<NodeSpec> nodes) {
+        List<NodeSpec> safeNodes = nodes == null ? List.of() : nodes;
+        StringBuilder sb = new StringBuilder();
+        sb.append("// SET Template: Ergebnis aus global.apiResult direkt per opc.write in OPC-UA Nodes schreiben\n");
+        sb.append("var result = global.apiResult;\n");
+        sb.append("if (!result) {\n");
+        sb.append("  throw \"global.apiResult ist leer. Vorher GET/POST Template oder RegLogin/API-Call ausfuehren.\";\n");
+        sb.append("}\n\n");
+        if (safeNodes.isEmpty()) {
+            sb.append("opc.write(\"ns=3;s=AirConditioner_1.ResultValue\", result.value);\n");
+        } else {
+            for (NodeSpec node : safeNodes) {
+                if (node == null || node.nodeId() == null || node.nodeId().isBlank()) continue;
+                String alias = safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+                sb.append("opc.write(").append(jsString(node.nodeId())).append(", result.").append(alias).append(" !== undefined ? result.").append(alias).append(" : result.value);\n");
+            }
+        }
+        sb.append("\nlog.info(\"OPC-UA SET abgeschlossen\");\n");
+        return sb.toString();
+    }
+
+    private static void appendReadVariables(StringBuilder sb, List<NodeSpec> nodes) {
+        if (nodes == null || nodes.isEmpty()) {
+            sb.append("// var Temperatur = Number(opc.read(\"ns=3;s=AirConditioner_1.Temperature\"));\n");
+            return;
+        }
+        for (NodeSpec node : nodes) {
+            if (node == null || node.nodeId() == null || node.nodeId().isBlank()) continue;
+            String alias = safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+            sb.append(read(node.nodeId(), alias, true));
+        }
+    }
+
+    private static void appendResponseHandling(StringBuilder sb) {
+        sb.append("if (response.status < 200 || response.status >= 300) {\n");
+        sb.append("  global.apiResult = { ok: false, status: response.status, body: response.body };\n");
+        sb.append("  throw \"REST Fehler HTTP \" + response.status + \": \" + response.body;\n");
+        sb.append("}\n\n");
+        sb.append("var result = JSON.parse(response.body);\n");
+        sb.append("global.apiResult = result;\n");
+        sb.append("log.info(\"REST Ergebnis gespeichert in global.apiResult\");\n");
+    }
+
+    public static String read(String nodeId, String alias, boolean number) {
+        String a = safeAlias(alias == null || alias.isBlank() ? aliasFromNodeId(nodeId) : alias);
+        String n = jsString(nodeId);
+        return number
+                ? "var " + a + " = Number(opc.read(" + n + "));\n"
+                : "var " + a + " = opc.read(" + n + ");\n";
+    }
+
+    public static String write(String nodeId, String expression) {
+        String valueExpression = expression == null || expression.isBlank() ? "/* Wert */" : expression.trim();
+        return "opc.write(" + jsString(nodeId) + ", " + valueExpression + ");\n";
+    }
+
+    public static String aliasFromNodeId(String nodeId) {
+        if (nodeId == null || nodeId.isBlank()) return "node";
+        int idxDot = nodeId.lastIndexOf('.');
+        int idxEq = nodeId.lastIndexOf('=');
+        int idx = Math.max(idxDot, idxEq);
+        String raw = idx >= 0 && idx < nodeId.length() - 1 ? nodeId.substring(idx + 1) : nodeId;
+        return safeAlias(raw);
+    }
+
+    public static String safeAlias(String text) {
+        if (text == null || text.isBlank()) return "node";
+        String alias = text.replaceAll("[^A-Za-z0-9_$]", "_");
+        if (!alias.matches("[A-Za-z_$].*")) alias = "n_" + alias;
+        return alias;
+    }
+
+    public static String jsString(String value) {
+        String v = value == null ? "" : value;
+        String escaped = v
+                .replace("\\", "\\\\")
+                .replace("\"", "\\\"")
+                .replace("\r", "\\r")
+                .replace("\n", "\\n");
+        return "\"" + escaped + "\"";
+    }
+
+
+
+    /**
+     * Renders a user configurable template. Supported placeholders:
+     *
+     * {{readNumberVars}}      -> var Alias = Number(opc.read("ns=..."));
+     * {{readTextVars}}        -> var Alias = opc.read("ns=...");
+     * {{payloadFields}}       -> Alias: Alias, lines for JSON payloads
+     * {{opcWritesFromResult}} -> opc.write("ns=...", result.Alias ?? result.value); lines
+     * {{selectedNodesComment}}-> comment block with selected NodeIds
+     * {{firstNodeId}}         -> first selected NodeId literal, without quotes
+     * {{firstNodeIdJs}}       -> first selected NodeId as JS string literal
+     * {{firstAlias}}          -> first selected alias
+     */
+    public static String renderTemplate(String template, List<NodeSpec> nodes) {
+        String source = template == null ? "" : template;
+        List<NodeSpec> safeNodes = nodes == null ? List.of() : nodes;
+        String firstNodeId = firstNodeId(safeNodes);
+        String firstAlias = firstAlias(safeNodes);
+        return source
+                .replace("{{readNumberVars}}", readVariables(safeNodes, true))
+                .replace("{{readTextVars}}", readVariables(safeNodes, false))
+                .replace("{{payloadFields}}", payloadFields(safeNodes))
+                .replace("{{opcWritesFromResult}}", opcWritesFromResult(safeNodes))
+                .replace("{{selectedNodesComment}}", selectedNodesComment(safeNodes))
+                .replace("{{firstNodeIdJs}}", jsString(firstNodeId))
+                .replace("{{firstNodeId}}", firstNodeId)
+                .replace("{{firstAlias}}", firstAlias);
+    }
+
+    public static String readVariables(List<NodeSpec> nodes, boolean number) {
+        List<NodeSpec> safeNodes = nodes == null ? List.of() : nodes;
+        if (safeNodes.isEmpty()) {
+            return number
+                    ? "// var Temperatur = Number(opc.read(\"ns=3;s=AirConditioner_1.Temperature\"));\n"
+                    : "// var Temperatur = opc.read(\"ns=3;s=AirConditioner_1.Temperature\");\n";
+        }
+        StringBuilder sb = new StringBuilder();
+        for (NodeSpec node : safeNodes) {
+            if (node == null || node.nodeId() == null || node.nodeId().isBlank()) continue;
+            String alias = safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+            sb.append(read(node.nodeId(), alias, number));
+        }
+        return sb.toString();
+    }
+
+    public static String payloadFields(List<NodeSpec> nodes) {
+        List<NodeSpec> safeNodes = nodes == null ? List.of() : nodes;
+        if (safeNodes.isEmpty()) return "  // keine Nodes ausgewaehlt\n";
+        StringBuilder sb = new StringBuilder();
+        for (NodeSpec node : safeNodes) {
+            if (node == null || node.nodeId() == null || node.nodeId().isBlank()) continue;
+            String alias = safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+            sb.append("  ").append(alias).append(": ").append(alias).append(",\n");
+        }
+        return sb.toString();
+    }
+
+    public static String opcWritesFromResult(List<NodeSpec> nodes) {
+        List<NodeSpec> safeNodes = nodes == null ? List.of() : nodes;
+        if (safeNodes.isEmpty()) {
+            return "// opc.write(\"ns=3;s=AirConditioner_1.ResultValue\", result.value);\n";
+        }
+        StringBuilder sb = new StringBuilder();
+        for (NodeSpec node : safeNodes) {
+            if (node == null || node.nodeId() == null || node.nodeId().isBlank()) continue;
+            String alias = safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+            sb.append("opc.write(").append(jsString(node.nodeId()))
+                    .append(", result.").append(alias).append(" !== undefined ? result.").append(alias).append(" : result.value);\n");
+        }
+        return sb.toString();
+    }
+
+    public static String selectedNodesComment(List<NodeSpec> nodes) {
+        List<NodeSpec> safeNodes = nodes == null ? List.of() : nodes;
+        if (safeNodes.isEmpty()) return "// Keine Nodes ausgewaehlt\n";
+        StringBuilder sb = new StringBuilder("// Ausgewaehlte Nodes:\n");
+        for (NodeSpec node : safeNodes) {
+            if (node == null || node.nodeId() == null || node.nodeId().isBlank()) continue;
+            String alias = safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+            sb.append("// - ").append(alias).append(" = ").append(node.nodeId()).append("\n");
+        }
+        return sb.toString();
+    }
+
+    private static String firstNodeId(List<NodeSpec> nodes) {
+        if (nodes != null) {
+            for (NodeSpec node : nodes) {
+                if (node != null && node.nodeId() != null && !node.nodeId().isBlank()) return node.nodeId();
+            }
+        }
+        return "ns=3;s=AirConditioner_1.Temperature";
+    }
+
+    private static String firstAlias(List<NodeSpec> nodes) {
+        if (nodes != null) {
+            for (NodeSpec node : nodes) {
+                if (node != null && node.nodeId() != null && !node.nodeId().isBlank()) {
+                    return safeAlias(node.alias() == null || node.alias().isBlank() ? aliasFromNodeId(node.nodeId()) : node.alias());
+                }
+            }
+        }
+        return "Temperatur";
+    }
+
+    public static List<NodeSpec> ofSingle(String nodeId, String alias) {
+        List<NodeSpec> list = new ArrayList<>();
+        list.add(new NodeSpec(nodeId, alias));
+        return list;
+    }
+}
diff --git a/src/main/java/de/opcua/app/scripting/Store.java b/src/main/java/de/opcua/app/scripting/Store.java
new file mode 100644
index 0000000..49a07d7
--- /dev/null
+++ b/src/main/java/de/opcua/app/scripting/Store.java
@@ -0,0 +1,13 @@
+package de.opcua.app.scripting;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public final class Store {
+  private final Map<String, Object> data = new ConcurrentHashMap<>();
+
+  public Object get(String key) { return data.get(key); }
+  public void set(String key, Object value) { data.put(key, value); }
+  public void clear() { data.clear(); }
+  public Map<String, Object> snapshot() { return Map.copyOf(data); }
+}
diff --git a/src/main/java/de/opcua/app/service/ActionPersistenceService.java b/src/main/java/de/opcua/app/service/ActionPersistenceService.java
new file mode 100644
index 0000000..d30d8a0
--- /dev/null
+++ b/src/main/java/de/opcua/app/service/ActionPersistenceService.java
@@ -0,0 +1,166 @@
+package de.opcua.app.service;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import de.opcua.app.config.AppPaths;
+import de.opcua.app.config.ConfigSecurity;
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.model.NodeAction;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Timer;
+import java.util.TimerTask;
+
+/**
+ * Persists Actions to <application-directory>/config/actions.json.
+ * When config encryption is enabled, this file is written as AES-GCM envelope JSON.
+ */
+public class ActionPersistenceService {
+
+    private static final Path ACTIONS_FILE = AppPaths.configFile("actions.json");
+    private static final Path LEGACY_ACTIONS_FILE = AppPaths.legacyUserConfigDirectory().resolve("actions.json");
+
+    private final ObjectMapper mapper;
+    private final SettingsService settingsService = new SettingsService();
+
+    public ActionPersistenceService() {
+        this.mapper = new ObjectMapper();
+        this.mapper.enable(SerializationFeature.INDENT_OUTPUT);
+        AppPaths.ensureConfigDirectory();
+        migrateLegacyIfNeeded();
+    }
+
+    public String getFilePath() {
+        return ACTIONS_FILE.toString();
+    }
+
+    public void saveActions(Map<String, List<NodeAction>> actions) {
+        try {
+            List<ActionData> dataList = new ArrayList<>();
+
+            for (Map.Entry<String, List<NodeAction>> entry : actions.entrySet()) {
+                String nodeId = entry.getKey();
+                for (NodeAction action : entry.getValue()) {
+                    ActionData data = new ActionData(
+                            nodeId,
+                            action.getActionName(),
+                            action.getTriggerType().name(),
+                            action.getScript(),
+                            action.getTriggerValue(),
+                            action.getIntervalMs(),
+                            action.isEnabled()
+                    );
+                    data.initEnabled = action.isInitEnabled();
+                    data.initScript = action.getInitScript();
+                    data.conditionEnabled = action.isConditionEnabled();
+                    data.conditionScript = action.getConditionScript();
+                    data.conditionNodeIds = new ArrayList<>(action.getConditionNodeIds());
+                    data.nodeAliases = new LinkedHashMap<>(action.getNodeAliases());
+                    dataList.add(data);
+                }
+            }
+
+            Settings settings = settingsService.load();
+            ConfigSecurity.writeText(ACTIONS_FILE, mapper.writeValueAsString(dataList), settings);
+            System.out.println("[Persistence] Saved " + dataList.size() + " actions to " + ACTIONS_FILE);
+
+        } catch (IOException e) {
+            System.err.println("[Persistence] Failed to save actions: " + e.getMessage());
+        }
+    }
+
+    public Map<String, List<NodeAction>> loadActions() {
+        Map<String, List<NodeAction>> result = new HashMap<>();
+        if (!Files.exists(ACTIONS_FILE)) {
+            System.out.println("[Persistence] No saved actions found at " + ACTIONS_FILE);
+            return result;
+        }
+
+        try {
+            Settings settings = settingsService.load();
+            String json = ConfigSecurity.readText(ACTIONS_FILE, settings);
+            ActionData[] dataArray = mapper.readValue(json, ActionData[].class);
+
+            for (ActionData data : dataArray) {
+                NodeAction action = new NodeAction();
+                action.setNodeId(data.nodeId);
+                action.setActionName(data.actionName);
+                action.setTriggerType(NodeAction.TriggerType.valueOf(data.triggerType));
+                action.setScript(data.script);
+                action.setTriggerValue(data.triggerValue);
+                action.setIntervalMs(data.intervalMs);
+                action.setEnabled(data.enabled);
+                action.setInitEnabled(data.initEnabled);
+                action.setInitScript(data.initScript);
+                action.setConditionEnabled(data.conditionEnabled);
+                action.setConditionScript(data.conditionScript);
+                action.setConditionNodeIds(data.conditionNodeIds);
+                action.setNodeAliases(data.nodeAliases);
+
+                result.computeIfAbsent(data.nodeId, k -> new ArrayList<>()).add(action);
+            }
+
+            System.out.println("[Persistence] Loaded " + dataArray.length + " actions from " + ACTIONS_FILE);
+
+        } catch (IOException e) {
+            System.err.println("[Persistence] Failed to load actions: " + e.getMessage());
+        }
+
+        return result;
+    }
+
+    public void startAutoSave(ActionService actionService, int intervalSeconds) {
+        Timer timer = new Timer("ActionAutoSave", true);
+        timer.scheduleAtFixedRate(new TimerTask() {
+            @Override public void run() { saveActions(actionService.getAllActions()); }
+        }, intervalSeconds * 1000L, intervalSeconds * 1000L);
+        System.out.println("[Persistence] Auto-save enabled (every " + intervalSeconds + "s)");
+    }
+
+    private void migrateLegacyIfNeeded() {
+        try {
+            if (Files.exists(ACTIONS_FILE) || !Files.exists(LEGACY_ACTIONS_FILE)) return;
+            Files.createDirectories(ACTIONS_FILE.getParent());
+            Files.copy(LEGACY_ACTIONS_FILE, ACTIONS_FILE);
+            System.out.println("[Persistence] Migrated legacy actions to " + ACTIONS_FILE);
+        } catch (Exception e) {
+            System.err.println("[Persistence] Legacy action migration skipped: " + e.getMessage());
+        }
+    }
+
+    public static class ActionData {
+        public String nodeId;
+        public String actionName;
+        public String triggerType;
+        public String script;
+        public String triggerValue;
+        public int intervalMs;
+        public boolean enabled;
+        public boolean initEnabled;
+        public String initScript;
+        public boolean conditionEnabled;
+        public String conditionScript;
+        public List<String> conditionNodeIds = new ArrayList<>();
+        public Map<String, String> nodeAliases = new LinkedHashMap<>();
+
+        public ActionData() {}
+        public ActionData(String nodeId, String actionName, String triggerType,
+                          String script, String triggerValue, int intervalMs, boolean enabled) {
+            this.nodeId = nodeId;
+            this.actionName = actionName;
+            this.triggerType = triggerType;
+            this.script = script;
+            this.triggerValue = triggerValue;
+            this.intervalMs = intervalMs;
+            this.enabled = enabled;
+        }
+    }
+}
diff --git a/src/main/java/de/opcua/app/service/ActionService.java b/src/main/java/de/opcua/app/service/ActionService.java
new file mode 100644
index 0000000..f6a531a
--- /dev/null
+++ b/src/main/java/de/opcua/app/service/ActionService.java
@@ -0,0 +1,607 @@
+package de.opcua.app.service;
+
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.scripting.GraalScriptEngine;
+import de.opcua.app.scripting.Store;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.stream.Collectors;
+
+/**
+ * Manages and executes actions associated with OPC UA nodes.
+ * Each triggered event is executed on its own worker thread. The JavaScript
+ * context is created per event in GraalScriptEngine, so variables from parallel
+ * events cannot overwrite each other.
+ */
+public class ActionService {
+
+    private final OpcUaService opcService;
+    private final GraalScriptEngine scriptEngine;
+    private final Map<String, List<NodeAction>> nodeActions;  // nodeId -> actions
+    private final ScheduledExecutorService scheduler;
+    private final ExecutorService eventExecutor;
+    private final ExecutorService initExecutor;
+    private final Map<String, ScheduledFuture<?>> intervalTasks;
+    private final Map<String, CompletableFuture<Void>> initTasks;
+    private static final String SYSTEM_INIT_SESSION_KEY = "__system_init__";
+    private final AtomicLong eventSequence = new AtomicLong();
+
+    public ActionService(OpcUaService opcService, Store store) {
+        this.opcService = opcService;
+        this.scriptEngine = new GraalScriptEngine(opcService, store);
+        this.nodeActions = new ConcurrentHashMap<>();
+        this.scheduler = Executors.newScheduledThreadPool(4, r -> {
+            Thread t = new Thread(r, "opcua-action-scheduler");
+            t.setDaemon(true);
+            return t;
+        });
+        this.eventExecutor = Executors.newCachedThreadPool(r -> {
+            long id = eventSequence.incrementAndGet();
+            Thread t = new Thread(r, "opcua-event-script-" + id);
+            t.setDaemon(true);
+            return t;
+        });
+        this.initExecutor = Executors.newSingleThreadExecutor(r -> {
+            Thread t = new Thread(r, "opcua-action-init");
+            t.setDaemon(true);
+            return t;
+        });
+        this.intervalTasks = new ConcurrentHashMap<>();
+        this.initTasks = new ConcurrentHashMap<>();
+    }
+
+    public void addAction(NodeAction action) {
+        if (action == null || action.getNodeId() == null || action.getNodeId().isBlank()) return;
+        String nodeId = action.getNodeId();
+        removeAction(nodeId, action.getActionName());
+        resetActionRuntimeState(action);
+        nodeActions.computeIfAbsent(nodeId, k -> new CopyOnWriteArrayList<>()).add(action);
+
+        if (action.getTriggerType() == NodeAction.TriggerType.ON_INTERVAL) {
+            scheduleIntervalAction(action);
+        }
+
+        System.out.println("Added action: " + action.getActionName() + " for node " + nodeId);
+    }
+
+    public void removeAction(String nodeId, String actionName) {
+        if (nodeId == null || actionName == null) return;
+        List<NodeAction> actions = nodeActions.get(nodeId);
+        if (actions != null) {
+            actions.removeIf(a -> actionName.equals(a.getActionName()));
+            if (actions.isEmpty()) nodeActions.remove(nodeId);
+
+            String taskKey = nodeId + ":" + actionName;
+            ScheduledFuture<?> task = intervalTasks.remove(taskKey);
+            if (task != null) task.cancel(false);
+
+            String runtimeKey = actionKey(nodeId, actionName);
+            initTasks.remove(runtimeKey);
+            scriptEngine.resetSessionScope(runtimeKey);
+        }
+    }
+
+    public List<NodeAction> getActions(String nodeId) {
+        return nodeActions.getOrDefault(nodeId, Collections.emptyList());
+    }
+
+    public Map<String, List<NodeAction>> getAllActions() {
+        return new HashMap<>(nodeActions);
+    }
+
+    public List<NodeAction> getAllActionsFlat() {
+        return nodeActions.values().stream()
+                .flatMap(List::stream)
+                .collect(Collectors.toList());
+    }
+
+
+
+    /**
+     * Execute the global system init script. This is independent from actions and is
+     * used for service startup/connect reglogin. Scripts can set global.session,
+     * global.apiResult, session.token, etc.
+     */
+    public Map<String, Object> executeSystemInitScript(String script, String reason, boolean resetSession) {
+        String initReason = reason == null || reason.isBlank() ? "manual-system-init" : reason;
+        Map<String, Object> summary = new LinkedHashMap<>();
+        summary.put("success", false);
+        summary.put("reason", initReason);
+        summary.put("connected", opcService.isConnected());
+
+        if (script == null || script.isBlank()) {
+            summary.put("skipped", true);
+            summary.put("message", "system init script is empty");
+            return summary;
+        }
+
+        if (resetSession) {
+            scriptEngine.resetSessionScope(SYSTEM_INIT_SESSION_KEY);
+        }
+
+        try {
+            Map<String, Object> bindings = buildSystemInitBindings(initReason, eventSequence.incrementAndGet());
+            Object result = scriptEngine.execute(script, bindings);
+            summary.put("success", true);
+            summary.put("skipped", false);
+            summary.put("result", result);
+            summary.put("globals", scriptEngine.getGlobalScope().snapshot());
+        } catch (Exception e) {
+            summary.put("error", e.getMessage());
+            System.err.println("[SystemInit] Failed: " + e.getMessage());
+        }
+        return summary;
+    }
+
+    public CompletableFuture<Map<String, Object>> executeSystemInitScriptAsync(String script, String reason, boolean resetSession) {
+        return CompletableFuture.supplyAsync(() -> executeSystemInitScript(script, reason, resetSession), initExecutor);
+    }
+
+    /**
+     * Run all enabled init scripts in the background.
+     *
+     * Use case:
+     * - program start: prepare REST/API sessions that do not need OPC UA
+     * - after OPC UA connect/reconnect: perform reglogin, read initial node values, refresh tokens
+     *
+     * If forceRerun is true, the per-action session scope is reset first. The shared
+     * global scope is intentionally kept so scripts can update values like
+     * global.session, global.apiResult or global.lastLogin.
+     */
+    public CompletableFuture<Map<String, Object>> initializeAllActionsAsync(String reason, boolean forceRerun) {
+        return CompletableFuture.supplyAsync(() -> initializeAllActions(reason, forceRerun), initExecutor);
+    }
+
+    /** Synchronous variant used by service mode and REST endpoints. */
+    public Map<String, Object> initializeAllActions(String reason, boolean forceRerun) {
+        String initReason = reason == null || reason.isBlank() ? "manual" : reason;
+        Map<String, Object> summary = new LinkedHashMap<>();
+        List<Map<String, Object>> details = new ArrayList<>();
+        int total = 0;
+        int success = 0;
+        int skipped = 0;
+        int failed = 0;
+
+        for (NodeAction action : getAllActionsFlat()) {
+            if (action == null || !action.isInitEnabled() || action.getInitScript() == null || action.getInitScript().isBlank()) {
+                skipped++;
+                continue;
+            }
+            if (!action.isEnabled()) {
+                skipped++;
+                details.add(initDetail(action, "skipped", "action disabled"));
+                continue;
+            }
+
+            total++;
+            if (forceRerun) {
+                resetActionRuntimeState(action);
+            }
+
+            try {
+                Map<String, Object> bindings = buildInitBindings(action, initReason, eventSequence.incrementAndGet());
+                ensureInitialized(action, bindings);
+                success++;
+                details.add(initDetail(action, "ok", "initialized"));
+            } catch (Exception e) {
+                failed++;
+                details.add(initDetail(action, "failed", e.getMessage()));
+                System.err.println("[Action Init] Failed for " + action.getActionName() + ": " + e.getMessage());
+            }
+        }
+
+        summary.put("success", failed == 0);
+        summary.put("reason", initReason);
+        summary.put("forceRerun", forceRerun);
+        summary.put("initActions", total);
+        summary.put("initialized", success);
+        summary.put("failed", failed);
+        summary.put("skipped", skipped);
+        summary.put("details", details);
+        return summary;
+    }
+
+    private Map<String, Object> initDetail(NodeAction action, String status, String message) {
+        Map<String, Object> detail = new LinkedHashMap<>();
+        detail.put("nodeId", action != null ? action.getNodeId() : null);
+        detail.put("actionName", action != null ? action.getActionName() : null);
+        detail.put("status", status);
+        detail.put("message", message);
+        return detail;
+    }
+
+    public void processValueChange(String nodeId, String newValue) {
+        List<NodeAction> actions = nodeActions.get(nodeId);
+        if (actions == null || actions.isEmpty()) return;
+
+        for (NodeAction action : actions) {
+            if (action.shouldTrigger(newValue)) {
+                executeAction(action, newValue);
+            }
+        }
+    }
+
+    private void executeAction(NodeAction action, String currentValue) {
+        eventExecutor.submit(() -> {
+            long eventId = eventSequence.incrementAndGet();
+            try {
+                System.out.println("Executing action: " + action.getActionName() +
+                        " for node " + action.getNodeId() +
+                        " with value: " + currentValue +
+                        " on " + Thread.currentThread().getName());
+
+                Map<String, Object> bindings = buildBindings(action, currentValue, eventId);
+                ensureInitialized(action, bindings);
+
+                if (action.isConditionEnabled() && action.getConditionScript() != null && !action.getConditionScript().isBlank()) {
+                    boolean conditionOk = scriptEngine.executeCondition(action.getConditionScript(), bindings);
+                    if (!conditionOk) {
+                        System.out.println("Action skipped by condition: " + action.getActionName());
+                        return;
+                    }
+                }
+
+                Object result = scriptEngine.execute(action.getScript(), bindings);
+                System.out.println("Action completed: " + action.getActionName() + " Result: " + result);
+
+            } catch (Exception e) {
+                System.err.println("Error executing action " + action.getActionName() + ": " + e.getMessage());
+                e.printStackTrace();
+            }
+        });
+    }
+
+    private void ensureInitialized(NodeAction action, Map<String, Object> bindings) {
+        if (action == null || !action.isInitEnabled() || action.getInitScript() == null || action.getInitScript().isBlank()) {
+            return;
+        }
+
+        String key = actionKey(action);
+        CompletableFuture<Void> future = initTasks.computeIfAbsent(key, ignored -> new CompletableFuture<>());
+
+        synchronized (future) {
+            if (!future.isDone()) {
+                try {
+                    Object reason = bindings != null ? bindings.get("initReason") : null;
+                    System.out.println("Initializing action session: " + action.getActionName() +
+                            (reason != null ? " [" + reason + "]" : ""));
+                    scriptEngine.execute(action.getInitScript(), bindings);
+                    future.complete(null);
+                    System.out.println("Action session initialized: " + action.getActionName());
+                } catch (Throwable t) {
+                    future.completeExceptionally(t);
+                    initTasks.remove(key);
+                    throw t;
+                }
+            }
+        }
+
+        try {
+            future.join();
+        } catch (CompletionException e) {
+            initTasks.remove(key);
+            Throwable cause = e.getCause() != null ? e.getCause() : e;
+            if (cause instanceof RuntimeException re) throw re;
+            throw new RuntimeException("Initial action script failed", cause);
+        }
+    }
+
+
+
+    private Map<String, Object> buildSystemInitBindings(String reason, long eventId) {
+        Map<String, Object> bindings = new LinkedHashMap<>();
+
+        Map<String, Object> event = new LinkedHashMap<>();
+        event.put("id", eventId);
+        event.put("thread", Thread.currentThread().getName());
+        event.put("type", "system-init");
+        event.put("init", true);
+        event.put("reason", reason);
+        event.put("connected", opcService.isConnected());
+
+        bindings.put("event", event);
+        bindings.put("init", true);
+        bindings.put("initReason", reason);
+        bindings.put("trigger", reason);
+        bindings.put("currentValue", "");
+        bindings.put("nodeId", "");
+        bindings.put("actionName", "SystemInit");
+        bindings.put("global", scriptEngine.getGlobalScope());
+        bindings.put("globals", scriptEngine.getGlobalScope());
+        bindings.put("session", scriptEngine.getSessionScope(SYSTEM_INIT_SESSION_KEY));
+        return bindings;
+    }
+
+    private Map<String, Object> buildInitBindings(NodeAction action, String reason, long eventId) {
+        String currentValue = "";
+        if (action != null && action.getNodeId() != null && opcService.isConnected()) {
+            try {
+                currentValue = opcService.readValueSync(action.getNodeId());
+            } catch (Exception e) {
+                currentValue = "<init-read-error: " + e.getMessage() + ">";
+            }
+        }
+
+        Map<String, Object> bindings = buildBindings(action, currentValue, eventId);
+        bindings.put("init", true);
+        bindings.put("initReason", reason);
+        bindings.put("trigger", reason);
+
+        Object eventObj = bindings.get("event");
+        if (eventObj instanceof Map<?, ?> eventMap) {
+            @SuppressWarnings("unchecked")
+            Map<String, Object> writableEvent = (Map<String, Object>) eventMap;
+            writableEvent.put("type", "init");
+            writableEvent.put("init", true);
+            writableEvent.put("reason", reason);
+            writableEvent.put("connected", opcService.isConnected());
+        }
+        return bindings;
+    }
+
+    private Map<String, Object> buildBindings(NodeAction action, String currentValue, long eventId) {
+        Map<String, Object> bindings = new LinkedHashMap<>();
+        Map<String, String> selectedNodes = new LinkedHashMap<>();      // alias -> nodeId
+        Map<String, String> selectedValues = new LinkedHashMap<>();     // alias -> current value
+        List<String> selectedNodeIds = action.getConditionNodeIds() != null
+                ? new ArrayList<>(action.getConditionNodeIds())
+                : new ArrayList<>();
+
+        if (!selectedNodeIds.contains(action.getNodeId())) {
+            selectedNodeIds.add(0, action.getNodeId());
+        }
+
+        Map<String, String> aliasesByNodeId = action.getNodeAliases() != null
+                ? action.getNodeAliases()
+                : Map.of();
+
+        for (String nodeId : selectedNodeIds) {
+            String alias = aliasesByNodeId.getOrDefault(nodeId, createAlias(nodeId));
+            alias = createSafeAlias(alias);
+            selectedNodes.put(alias, nodeId);
+
+            String value;
+            if (nodeId.equals(action.getNodeId())) {
+                value = currentValue;
+            } else {
+                try {
+                    value = opcService.readValueSync(nodeId);
+                } catch (Exception e) {
+                    value = "<error: " + e.getMessage() + ">";
+                }
+            }
+            selectedValues.put(alias, value);
+
+            // No direct JavaScript variables are created from UI selections.
+            // Scripts should be self-contained, for example:
+            // var Temperature = opc.read("ns=2;s=Temperature");
+        }
+
+        Map<String, Object> event = new LinkedHashMap<>();
+        event.put("id", eventId);
+        event.put("thread", Thread.currentThread().getName());
+        event.put("nodeId", action.getNodeId());
+        event.put("actionName", action.getActionName());
+        event.put("currentValue", currentValue);
+        event.put("selectedNodeIds", selectedNodeIds);
+        event.put("nodes", selectedNodes);
+        event.put("values", selectedValues);
+
+        bindings.put("event", event);
+        bindings.put("currentValue", currentValue);
+        bindings.put("nodeId", action.getNodeId());
+        bindings.put("actionName", action.getActionName());
+        bindings.put("selectedNodeIds", selectedNodeIds);
+        bindings.put("nodes", selectedNodes);
+        bindings.put("selectedNodes", selectedNodes);
+        bindings.put("values", selectedValues);
+        bindings.put("selectedValues", selectedValues);
+        bindings.put("global", scriptEngine.getGlobalScope());
+        bindings.put("globals", scriptEngine.getGlobalScope());
+        bindings.put("session", scriptEngine.getSessionScope(actionKey(action)));
+
+        return bindings;
+    }
+
+    private String actionKey(NodeAction action) {
+        return action == null ? "unknown" : actionKey(action.getNodeId(), action.getActionName());
+    }
+
+    private String actionKey(String nodeId, String actionName) {
+        return String.valueOf(nodeId) + "::" + String.valueOf(actionName);
+    }
+
+    private void resetActionRuntimeState(NodeAction action) {
+        String key = actionKey(action);
+        initTasks.remove(key);
+        scriptEngine.resetSessionScope(key);
+    }
+
+    private String createAlias(String nodeId) {
+        if (nodeId == null) return "node";
+        int idx = Math.max(nodeId.lastIndexOf('.'), nodeId.lastIndexOf('='));
+        String raw = idx >= 0 && idx < nodeId.length() - 1 ? nodeId.substring(idx + 1) : nodeId;
+        return createSafeAlias(raw);
+    }
+
+    private String createSafeAlias(String text) {
+        if (text == null || text.isBlank()) return "node";
+        String alias = text.replaceAll("[^A-Za-z0-9_$]", "_");
+        if (!alias.matches("[A-Za-z_$].*")) alias = "n_" + alias;
+        return alias;
+    }
+
+    private void scheduleIntervalAction(NodeAction action) {
+        String taskKey = action.getNodeId() + ":" + action.getActionName();
+
+        ScheduledFuture<?> existingTask = intervalTasks.get(taskKey);
+        if (existingTask != null) existingTask.cancel(false);
+
+        int interval = Math.max(100, action.getIntervalMs());
+        ScheduledFuture<?> task = scheduler.scheduleAtFixedRate(() -> {
+            if (action.isEnabled()) {
+                try {
+                    String currentValue = opcService.readValue(action.getNodeId()).get(5, TimeUnit.SECONDS);
+                    executeAction(action, currentValue);
+                } catch (Exception e) {
+                    System.err.println("Error in interval action " + action.getActionName() + ": " + e.getMessage());
+                }
+            }
+        }, interval, interval, TimeUnit.MILLISECONDS);
+
+        intervalTasks.put(taskKey, task);
+    }
+
+    public void setActionEnabled(String nodeId, String actionName, boolean enabled) {
+        List<NodeAction> actions = nodeActions.get(nodeId);
+        if (actions != null) {
+            actions.stream()
+                    .filter(a -> a.getActionName().equals(actionName))
+                    .forEach(a -> a.setEnabled(enabled));
+        }
+    }
+
+    public void testAction(String nodeId, String actionName, String testValue) {
+        List<NodeAction> actions = nodeActions.get(nodeId);
+        if (actions != null) {
+            actions.stream()
+                    .filter(a -> a.getActionName().equals(actionName))
+                    .forEach(a -> executeAction(a, testValue));
+        }
+    }
+
+    public GraalScriptEngine getScriptEngine() {
+        return scriptEngine;
+    }
+
+    public void shutdown() {
+        intervalTasks.values().forEach(task -> task.cancel(false));
+        intervalTasks.clear();
+        initTasks.clear();
+
+        scheduler.shutdown();
+        eventExecutor.shutdown();
+        initExecutor.shutdown();
+        try {
+            if (!scheduler.awaitTermination(5, TimeUnit.SECONDS)) scheduler.shutdownNow();
+            if (!eventExecutor.awaitTermination(10, TimeUnit.SECONDS)) eventExecutor.shutdownNow();
+            if (!initExecutor.awaitTermination(10, TimeUnit.SECONDS)) initExecutor.shutdownNow();
+        } catch (InterruptedException e) {
+            scheduler.shutdownNow();
+            eventExecutor.shutdownNow();
+            initExecutor.shutdownNow();
+            Thread.currentThread().interrupt();
+        }
+
+        scriptEngine.close();
+    }
+
+    public Map<String, Object> exportActions() {
+        Map<String, Object> export = new HashMap<>();
+
+        for (Map.Entry<String, List<NodeAction>> entry : nodeActions.entrySet()) {
+            List<Map<String, Object>> actionsList = entry.getValue().stream()
+                    .map(this::actionToMap)
+                    .collect(Collectors.toList());
+            export.put(entry.getKey(), actionsList);
+        }
+
+        return export;
+    }
+
+    private Map<String, Object> actionToMap(NodeAction action) {
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("actionName", action.getActionName());
+        map.put("triggerType", action.getTriggerType().name());
+        map.put("script", action.getScript());
+        map.put("initEnabled", action.isInitEnabled());
+        map.put("initScript", action.getInitScript());
+        map.put("triggerValue", action.getTriggerValue());
+        map.put("intervalMs", action.getIntervalMs());
+        map.put("enabled", action.isEnabled());
+        map.put("conditionEnabled", action.isConditionEnabled());
+        map.put("conditionScript", action.getConditionScript());
+        map.put("conditionNodeIds", action.getConditionNodeIds());
+        map.put("nodeAliases", action.getNodeAliases());
+        return map;
+    }
+
+    public void importActions(Map<String, Object> data) {
+        nodeActions.clear();
+
+        for (Map.Entry<String, Object> entry : data.entrySet()) {
+            String nodeId = entry.getKey();
+            @SuppressWarnings("unchecked")
+            List<Map<String, Object>> actionsList = (List<Map<String, Object>>) entry.getValue();
+
+            for (Map<String, Object> actionMap : actionsList) {
+                NodeAction action = mapToAction(nodeId, actionMap);
+                addAction(action);
+            }
+        }
+    }
+
+    public void importActionsFromList(Map<String, List<NodeAction>> data) {
+        nodeActions.clear();
+
+        for (Map.Entry<String, List<NodeAction>> entry : data.entrySet()) {
+            for (NodeAction action : entry.getValue()) {
+                addAction(action);
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private NodeAction mapToAction(String nodeId, Map<String, Object> map) {
+        NodeAction action = new NodeAction();
+        action.setNodeId(nodeId);
+        action.setActionName((String) map.get("actionName"));
+        action.setTriggerType(NodeAction.TriggerType.valueOf((String) map.get("triggerType")));
+        action.setScript((String) map.get("script"));
+        Object initEnabled = map.get("initEnabled");
+        if (initEnabled instanceof Boolean) action.setInitEnabled((Boolean) initEnabled);
+        action.setInitScript((String) map.getOrDefault("initScript", ""));
+        action.setTriggerValue((String) map.get("triggerValue"));
+
+        Object intervalMs = map.get("intervalMs");
+        if (intervalMs instanceof Number) action.setIntervalMs(((Number) intervalMs).intValue());
+
+        Object enabled = map.get("enabled");
+        if (enabled instanceof Boolean) action.setEnabled((Boolean) enabled);
+
+        Object conditionEnabled = map.get("conditionEnabled");
+        if (conditionEnabled instanceof Boolean) action.setConditionEnabled((Boolean) conditionEnabled);
+
+        action.setConditionScript((String) map.getOrDefault("conditionScript", ""));
+
+        Object conditionNodeIds = map.get("conditionNodeIds");
+        if (conditionNodeIds instanceof List<?>) {
+            action.setConditionNodeIds(((List<?>) conditionNodeIds).stream().map(String::valueOf).collect(Collectors.toList()));
+        }
+
+        Object nodeAliases = map.get("nodeAliases");
+        if (nodeAliases instanceof Map<?, ?> aliases) {
+            Map<String, String> converted = new LinkedHashMap<>();
+            aliases.forEach((k, v) -> converted.put(String.valueOf(k), String.valueOf(v)));
+            action.setNodeAliases(converted);
+        }
+
+        return action;
+    }
+}
diff --git a/src/main/java/de/opcua/app/service/AppMode.java b/src/main/java/de/opcua/app/service/AppMode.java
new file mode 100644
index 0000000..328a9f9
--- /dev/null
+++ b/src/main/java/de/opcua/app/service/AppMode.java
@@ -0,0 +1,15 @@
+package de.opcua.app.service;
+
+public enum AppMode {
+  UI,
+  SERVICE;
+
+  public static AppMode fromArgs(String[] args) {
+    if (args == null) return UI;
+    for (String a : args) {
+      if (a == null) continue;
+      if (a.equalsIgnoreCase("--service") || a.equalsIgnoreCase("service")) return SERVICE;
+    }
+    return UI;
+  }
+}
diff --git a/src/main/java/de/opcua/app/service/ScriptTemplateService.java b/src/main/java/de/opcua/app/service/ScriptTemplateService.java
new file mode 100644
index 0000000..c8d2a10
--- /dev/null
+++ b/src/main/java/de/opcua/app/service/ScriptTemplateService.java
@@ -0,0 +1,253 @@
+package de.opcua.app.service;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import de.opcua.app.config.AppPaths;
+import de.opcua.app.config.ConfigSecurity;
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.model.ScriptTemplate;
+import de.opcua.app.scripting.ScriptSnippetBuilder;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Stores user configurable JavaScript templates in <application-directory>/config/script-templates.json.
+ *
+ * The built-in GET/POST/SET templates are only defaults. Users may edit them,
+ * disable them or add any number of own templates. Rendering expands placeholders
+ * into explicit JavaScript lines with fixed NodeId literals.
+ */
+public class ScriptTemplateService {
+    private final ObjectMapper mapper = new ObjectMapper();
+    private final SettingsService settingsService = new SettingsService();
+    private final Path file;
+
+    public ScriptTemplateService() {
+        this(AppPaths.configFile("script-templates.json"));
+    }
+
+    public ScriptTemplateService(Path file) {
+        this.file = file;
+    }
+
+    public String getFilePath() {
+        return file.toString();
+    }
+
+    public synchronized List<ScriptTemplate> load() throws IOException {
+        Files.createDirectories(file.getParent());
+        migrateLegacyIfNeeded();
+        if (!Files.exists(file)) {
+            List<ScriptTemplate> defaults = defaultTemplates();
+            save(defaults);
+            return defaults;
+        }
+        Settings settings = settingsService.load();
+        String json = ConfigSecurity.readText(file, settings);
+        List<ScriptTemplate> loaded = mapper.readValue(json, new TypeReference<List<ScriptTemplate>>() {});
+        if (loaded == null || loaded.isEmpty()) {
+            loaded = defaultTemplates();
+            save(loaded);
+        }
+        return normalizeList(loaded, false);
+    }
+
+    public synchronized List<ScriptTemplate> save(List<ScriptTemplate> templates) throws IOException {
+        Files.createDirectories(file.getParent());
+        List<ScriptTemplate> normalized = normalizeList(templates, true);
+        Settings settings = settingsService.load();
+        ConfigSecurity.writeText(file, mapper.writerWithDefaultPrettyPrinter().writeValueAsString(normalized), settings);
+        return normalized;
+    }
+
+    public synchronized ScriptTemplate upsert(ScriptTemplate template) throws IOException {
+        List<ScriptTemplate> templates = new ArrayList<>(load());
+        ScriptTemplate normalized = normalize(template, true);
+        boolean replaced = false;
+        for (int i = 0; i < templates.size(); i++) {
+            ScriptTemplate existing = templates.get(i);
+            if (equalsIdOrName(existing, normalized.getId(), normalized.getName())) {
+                if (existing.isBuiltIn()) normalized.setBuiltIn(true);
+                templates.set(i, normalized);
+                replaced = true;
+                break;
+            }
+        }
+        if (!replaced) templates.add(normalized);
+        save(templates);
+        return normalized;
+    }
+
+    public synchronized boolean delete(String idOrName) throws IOException {
+        if (idOrName == null || idOrName.isBlank()) return false;
+        List<ScriptTemplate> templates = new ArrayList<>(load());
+        boolean removed = templates.removeIf(t -> equalsIdOrName(t, idOrName, idOrName));
+        if (removed) save(templates);
+        return removed;
+    }
+
+    public synchronized List<ScriptTemplate> resetDefaults() throws IOException {
+        List<ScriptTemplate> defaults = defaultTemplates();
+        save(defaults);
+        return defaults;
+    }
+
+    public synchronized ScriptTemplate find(String idOrName) throws IOException {
+        if (idOrName == null || idOrName.isBlank()) return null;
+        for (ScriptTemplate template : load()) {
+            if (equalsIdOrName(template, idOrName, idOrName)) return template;
+        }
+        return null;
+    }
+
+    public synchronized String render(String idOrName, List<ScriptSnippetBuilder.NodeSpec> nodes) throws IOException {
+        ScriptTemplate template = find(idOrName);
+        if (template == null) {
+            throw new IllegalArgumentException("Template nicht gefunden: " + idOrName);
+        }
+        if (!template.isEnabled()) {
+            throw new IllegalArgumentException("Template ist deaktiviert: " + template.getName());
+        }
+        return ScriptSnippetBuilder.renderTemplate(template.getScript(), nodes);
+    }
+
+
+    private void migrateLegacyIfNeeded() {
+        try {
+            Path legacy = AppPaths.legacyUserConfigDirectory().resolve("script-templates.json");
+            if (Files.exists(file) || !Files.exists(legacy)) return;
+            Files.createDirectories(file.getParent());
+            Files.copy(legacy, file);
+            System.out.println("[Templates] Migrated legacy templates to " + file);
+        } catch (Exception e) {
+            System.err.println("[Templates] Legacy migration skipped: " + e.getMessage());
+        }
+    }
+
+    public List<ScriptTemplate> defaultTemplates() {
+        List<ScriptTemplate> defaults = new ArrayList<>();
+        defaults.add(new ScriptTemplate("get", "GET", """
+// GET Template: OPC-UA Werte lesen, REST GET aufrufen, Ergebnis global merken
+{{readNumberVars}}
+var query = {
+{{payloadFields}}  eventNode: event.nodeId,
+  eventValue: currentValue
+};
+
+var url = "http://localhost:9000/api/process?" + Object.keys(query)
+  .map(function(k) { return encodeURIComponent(k) + "=" + encodeURIComponent(String(query[k])); })
+  .join("&");
+
+var response = http.get(url, {
+  Authorization: "Bearer " + (global.session && global.session.token ? global.session.token : "")
+});
+
+if (response.status < 200 || response.status >= 300) {
+  global.apiResult = { ok: false, status: response.status, body: response.body };
+  throw "REST Fehler HTTP " + response.status + ": " + response.body;
+}
+
+var result = JSON.parse(response.body);
+global.apiResult = result;
+log.info("GET Ergebnis in global.apiResult gespeichert");
+
+// Optional direkt in OPC-UA schreiben:
+{{opcWritesFromResult}}
+""", true, true));
+        defaults.add(new ScriptTemplate("post", "POST", """
+// POST Template: OPC-UA Werte lesen, REST POST senden, Ergebnis global merken
+{{readNumberVars}}
+var payload = {
+{{payloadFields}}  eventNode: event.nodeId,
+  eventValue: currentValue,
+  timestamp: new Date().toISOString()
+};
+
+var response = http.postJson("http://localhost:9000/api/process", payload, {
+  Authorization: "Bearer " + (global.session && global.session.token ? global.session.token : "")
+});
+
+if (response.status < 200 || response.status >= 300) {
+  global.apiResult = { ok: false, status: response.status, body: response.body };
+  throw "REST Fehler HTTP " + response.status + ": " + response.body;
+}
+
+var result = JSON.parse(response.body);
+global.apiResult = result;
+log.info("POST Ergebnis in global.apiResult gespeichert");
+
+// Optional direkt in OPC-UA schreiben:
+{{opcWritesFromResult}}
+""", true, true));
+        defaults.add(new ScriptTemplate("set", "SET / opc.write", """
+// SET Template: Ergebnis aus global.apiResult per opc.write in OPC-UA Nodes schreiben
+var result = global.apiResult;
+if (!result) {
+  throw "global.apiResult ist leer. Vorher GET/POST/API-Call oder RegLogin ausfuehren.";
+}
+
+{{opcWritesFromResult}}
+log.info("OPC-UA SET abgeschlossen");
+""", true, true));
+        return defaults;
+    }
+
+    private List<ScriptTemplate> normalizeList(List<ScriptTemplate> templates, boolean touchUpdatedAt) {
+        Map<String, ScriptTemplate> byId = new LinkedHashMap<>();
+        Set<String> usedIds = new LinkedHashSet<>();
+        List<ScriptTemplate> input = templates == null ? List.of() : templates;
+        for (ScriptTemplate template : input) {
+            ScriptTemplate normalized = normalize(template, touchUpdatedAt);
+            if (normalized.getName() == null || normalized.getName().isBlank()) continue;
+            String id = normalized.getId();
+            if (usedIds.contains(id)) {
+                int n = 2;
+                String base = id;
+                while (usedIds.contains(base + "-" + n)) n++;
+                id = base + "-" + n;
+                normalized.setId(id);
+            }
+            usedIds.add(id);
+            byId.put(id, normalized);
+        }
+        return new ArrayList<>(byId.values());
+    }
+
+    private ScriptTemplate normalize(ScriptTemplate template, boolean touchUpdatedAt) {
+        ScriptTemplate t = template == null ? new ScriptTemplate() : template;
+        String name = t.getName() == null || t.getName().isBlank() ? "Template" : t.getName().trim();
+        String id = t.getId() == null || t.getId().isBlank() ? slug(name) : slug(t.getId());
+        if (id.isBlank()) id = slug(name);
+        t.setName(name);
+        t.setId(id);
+        if (t.getScript() == null) t.setScript("");
+        if (touchUpdatedAt || t.getUpdatedAt() <= 0) t.setUpdatedAt(System.currentTimeMillis());
+        return t;
+    }
+
+    private boolean equalsIdOrName(ScriptTemplate template, String id, String name) {
+        if (template == null) return false;
+        String tid = template.getId() == null ? "" : template.getId().trim().toLowerCase(Locale.ROOT);
+        String tname = template.getName() == null ? "" : template.getName().trim().toLowerCase(Locale.ROOT);
+        String sid = id == null ? "" : slug(id).toLowerCase(Locale.ROOT);
+        String sname = name == null ? "" : name.trim().toLowerCase(Locale.ROOT);
+        return (!sid.isBlank() && tid.equals(sid)) || (!sname.isBlank() && tname.equals(sname));
+    }
+
+    public static String slug(String text) {
+        if (text == null) return "";
+        String slug = text.trim().toLowerCase(Locale.ROOT).replaceAll("[^a-z0-9]+", "-");
+        slug = slug.replaceAll("^-+", "").replaceAll("-+$", "");
+        return slug;
+    }
+}
diff --git a/src/main/java/de/opcua/app/service/SystemInitScriptService.java b/src/main/java/de/opcua/app/service/SystemInitScriptService.java
new file mode 100644
index 0000000..3d03c90
--- /dev/null
+++ b/src/main/java/de/opcua/app/service/SystemInitScriptService.java
@@ -0,0 +1,65 @@
+package de.opcua.app.service;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import de.opcua.app.config.AppPaths;
+import de.opcua.app.config.ConfigSecurity;
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.model.SystemInitScript;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+/**
+ * Persists the global init/reglogin script in <application-directory>/config.
+ */
+public class SystemInitScriptService {
+    private static final Path FILE = AppPaths.configFile("system-init-script.json");
+    private static final Path LEGACY_FILE = AppPaths.legacyUserConfigDirectory().resolve("system-init-script.json");
+
+    private final ObjectMapper mapper;
+    private final SettingsService settingsService = new SettingsService();
+
+    public SystemInitScriptService() {
+        this.mapper = new ObjectMapper();
+        this.mapper.enable(SerializationFeature.INDENT_OUTPUT);
+        AppPaths.ensureConfigDirectory();
+        migrateLegacyIfNeeded();
+    }
+
+    public SystemInitScript load() {
+        if (!Files.exists(FILE)) return new SystemInitScript();
+        try {
+            Settings settings = settingsService.load();
+            String json = ConfigSecurity.readText(FILE, settings);
+            SystemInitScript config = mapper.readValue(json, SystemInitScript.class);
+            if (config.getScript() == null) config.setScript("");
+            return config;
+        } catch (IOException e) {
+            System.err.println("[SystemInit] Failed to load " + FILE + ": " + e.getMessage());
+            return new SystemInitScript();
+        }
+    }
+
+    public void save(SystemInitScript config) throws IOException {
+        if (config == null) config = new SystemInitScript();
+        config.setUpdatedAt(System.currentTimeMillis());
+        Settings settings = settingsService.load();
+        ConfigSecurity.writeText(FILE, mapper.writeValueAsString(config), settings);
+    }
+
+    public String getFilePath() { return FILE.toString(); }
+
+    private void migrateLegacyIfNeeded() {
+        try {
+            if (Files.exists(FILE) || !Files.exists(LEGACY_FILE)) return;
+            Files.createDirectories(FILE.getParent());
+            Files.copy(LEGACY_FILE, FILE);
+            System.out.println("[SystemInit] Migrated legacy config to " + FILE);
+        } catch (Exception e) {
+            System.err.println("[SystemInit] Legacy migration skipped: " + e.getMessage());
+        }
+    }
+}
diff --git a/src/main/java/de/opcua/app/test/MinimalRestTest.java b/src/main/java/de/opcua/app/test/MinimalRestTest.java
new file mode 100644
index 0000000..caac88d
--- /dev/null
+++ b/src/main/java/de/opcua/app/test/MinimalRestTest.java
@@ -0,0 +1,66 @@
+package de.opcua.app.test;
+
+import com.sun.net.httpserver.*;
+import java.io.*;
+import java.net.InetSocketAddress;
+
+/**
+ * Minimal test to verify HttpServer works
+ * Run with: mvn exec:java -Dexec.mainClass="de.opcua.app.test.MinimalRestTest"
+ */
+public class MinimalRestTest {
+    
+    public static void main(String[] args) {
+        try {
+            System.out.println("Creating HTTP Server on port 8081...");
+            
+            HttpServer server = HttpServer.create(new InetSocketAddress(8081), 0);
+            
+            server.createContext("/", exchange -> {
+                String html = "<html><body><h1>It Works!</h1><p>REST API is running on port 8081</p></body></html>";
+                byte[] bytes = html.getBytes("UTF-8");
+                
+                exchange.getResponseHeaders().set("Content-Type", "text/html; charset=UTF-8");
+                exchange.sendResponseHeaders(200, bytes.length);
+                exchange.getResponseBody().write(bytes);
+                exchange.getResponseBody().close();
+            });
+            
+            server.createContext("/test", exchange -> {
+                String json = "{\"status\":\"ok\",\"message\":\"Test endpoint works!\"}";
+                byte[] bytes = json.getBytes("UTF-8");
+                
+                exchange.getResponseHeaders().set("Content-Type", "application/json");
+                exchange.sendResponseHeaders(200, bytes.length);
+                exchange.getResponseBody().write(bytes);
+                exchange.getResponseBody().close();
+            });
+            
+            server.start();
+            
+            System.out.println("✅ HTTP Server started successfully!");
+            System.out.println("✅ Open in browser: http://localhost:8081/");
+            System.out.println("✅ Test endpoint: http://localhost:8081/test");
+            System.out.println("");
+            System.out.println("Test with curl:");
+            System.out.println("  curl http://localhost:8081/");
+            System.out.println("  curl http://localhost:8081/test");
+            System.out.println("");
+            System.out.println("Press Ctrl+C to stop...");
+            
+            Thread.sleep(Long.MAX_VALUE);
+            
+        } catch (Exception e) {
+            System.err.println("❌ Failed to start server!");
+            System.err.println("Error: " + e.getMessage());
+            e.printStackTrace();
+            
+            System.err.println("");
+            System.err.println("Possible causes:");
+            System.err.println("1. Port 8081 is already in use");
+            System.err.println("   Check with: lsof -i :8081");
+            System.err.println("2. Firewall is blocking the port");
+            System.err.println("3. Insufficient permissions");
+        }
+    }
+}
diff --git a/src/main/java/de/opcua/app/ui/ActionButtonHelper.java b/src/main/java/de/opcua/app/ui/ActionButtonHelper.java
new file mode 100644
index 0000000..bbbd837
--- /dev/null
+++ b/src/main/java/de/opcua/app/ui/ActionButtonHelper.java
@@ -0,0 +1,352 @@
+package de.opcua.app.ui;
+
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.model.NodeRow;
+import de.opcua.app.model.ScriptTemplate;
+import de.opcua.app.scripting.ScriptSnippetBuilder;
+import de.opcua.app.service.ActionService;
+import de.opcua.app.service.ScriptTemplateService;
+import javafx.application.Platform;
+import javafx.geometry.Insets;
+import javafx.geometry.Pos;
+import javafx.scene.control.*;
+import javafx.scene.layout.GridPane;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.Priority;
+import javafx.scene.layout.VBox;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+/**
+ * Action editor for monitored OPC UA nodes.
+ *
+ * Node selections are used only to generate copyable JavaScript code with fixed
+ * NodeIds. Saved actions do not depend on runtime checkbox state.
+ */
+public class ActionButtonHelper {
+
+    private final ActionService actionService;
+    private final Supplier<List<NodeRow>> monitoredNodesSupplier;
+    private final ScriptTemplateService scriptTemplateService = new ScriptTemplateService();
+
+    public ActionButtonHelper(ActionService actionService) {
+        this(actionService, List::of);
+    }
+
+    public ActionButtonHelper(ActionService actionService, Supplier<List<NodeRow>> monitoredNodesSupplier) {
+        this.actionService = actionService;
+        this.monitoredNodesSupplier = monitoredNodesSupplier != null ? monitoredNodesSupplier : List::of;
+    }
+
+    public TableColumn<NodeRow, Void> createActionColumn() {
+        TableColumn<NodeRow, Void> actionCol = new TableColumn<>("Actions");
+        actionCol.setPrefWidth(130);
+        actionCol.setCellFactory(param -> new TableCell<>() {
+            private final Button btnActions = new Button("Actions");
+            private final HBox container = new HBox(5, btnActions);
+            {
+                btnActions.setMaxWidth(Double.MAX_VALUE);
+                container.setAlignment(Pos.CENTER);
+                btnActions.setOnAction(event -> {
+                    NodeRow row = getTableView().getItems().get(getIndex());
+                    if (row != null && row.isSelected()) showActionDialog(row);
+                });
+            }
+            @Override protected void updateItem(Void item, boolean empty) {
+                super.updateItem(item, empty);
+                if (empty || getIndex() >= getTableView().getItems().size()) setGraphic(null);
+                else {
+                    NodeRow row = getTableView().getItems().get(getIndex());
+                    setGraphic(row != null && row.isSelected() && row.isReadable() ? container : null);
+                }
+            }
+        });
+        return actionCol;
+    }
+
+    private void showActionDialog(NodeRow nodeRow) {
+        Dialog<ButtonType> dialog = new Dialog<>();
+        dialog.setTitle("Manage Actions");
+        dialog.setHeaderText("Actions for: " + nodeRow.getDisplayName() + "\nNode: " + nodeRow.getNodeId());
+
+        VBox mainBox = new VBox(10);
+        mainBox.setPadding(new Insets(10));
+        mainBox.setPrefSize(800, 520);
+
+        ListView<NodeAction> actionList = new ListView<>();
+        actionList.setPrefHeight(340);
+        actionList.getItems().addAll(actionService.getActions(nodeRow.getNodeId()));
+        VBox.setVgrow(actionList, Priority.ALWAYS);
+
+        actionList.setCellFactory(param -> new ListCell<>() {
+            @Override protected void updateItem(NodeAction action, boolean empty) {
+                super.updateItem(action, empty);
+                if (empty || action == null) {
+                    setGraphic(null);
+                    return;
+                }
+                HBox cell = new HBox(10);
+                cell.setAlignment(Pos.CENTER_LEFT);
+                cell.setPadding(new Insets(5));
+
+                CheckBox enabled = new CheckBox();
+                enabled.setSelected(action.isEnabled());
+                enabled.setOnAction(e -> actionService.setActionEnabled(action.getNodeId(), action.getActionName(), enabled.isSelected()));
+
+                Label label = new Label(action.getActionName() + " (" + action.getTriggerType() + ")"
+                        + (action.isInitEnabled() ? " · init" : "")
+                        + (action.isConditionEnabled() ? " · condition" : ""));
+                label.setMinWidth(310);
+                HBox.setHgrow(label, Priority.ALWAYS);
+
+                Button btnEdit = new Button("Edit");
+                btnEdit.setOnAction(e -> { editAction(action); actionList.refresh(); });
+
+                Button btnTest = new Button("Test");
+                btnTest.setOnAction(e -> testAction(action, nodeRow));
+
+                Button btnDelete = new Button("Delete");
+                btnDelete.setOnAction(e -> {
+                    actionService.removeAction(action.getNodeId(), action.getActionName());
+                    actionList.getItems().remove(action);
+                });
+                cell.getChildren().addAll(enabled, label, btnEdit, btnTest, btnDelete);
+                setGraphic(cell);
+            }
+        });
+
+        Button addButton = new Button("Add New Action");
+        addButton.setOnAction(e -> {
+            NodeAction newAction = editActionDialog(null, nodeRow);
+            if (newAction != null) {
+                actionService.addAction(newAction);
+                actionList.getItems().add(newAction);
+            }
+        });
+
+        mainBox.getChildren().addAll(actionList, new HBox(10, addButton));
+        dialog.getDialogPane().setContent(mainBox);
+        dialog.getDialogPane().getButtonTypes().addAll(ButtonType.CLOSE);
+        dialog.setResizable(true);
+        dialog.showAndWait();
+    }
+
+    private void editAction(NodeAction action) {
+        String oldNodeId = action.getNodeId();
+        String oldName = action.getActionName();
+        NodeRow triggerRow = new NodeRow(true, action.getActionName(), "Variable", action.getNodeId(), "", "", "");
+        NodeAction edited = editActionDialog(action, triggerRow);
+        if (edited != null) {
+            if (!String.valueOf(oldName).equals(edited.getActionName()) || !String.valueOf(oldNodeId).equals(edited.getNodeId())) {
+                actionService.removeAction(oldNodeId, oldName);
+            }
+            actionService.addAction(edited);
+        }
+    }
+
+    private NodeAction editActionDialog(NodeAction existing, NodeRow triggerRow) {
+        boolean create = existing == null;
+        Dialog<NodeAction> dialog = new Dialog<>();
+        dialog.setTitle(create ? "Create New Action" : "Edit Action");
+        dialog.setHeaderText((create ? "Add action for: " : "Edit action for: ") + triggerRow.getNodeId());
+        dialog.setResizable(true);
+
+        VBox main = new VBox(12);
+        main.setPadding(new Insets(16));
+        main.setPrefSize(900, 760);
+
+        TextField nameField = new TextField(create ? "" : existing.getActionName());
+        nameField.setPromptText("z. B. Temperatur_Alarm");
+
+        ComboBox<NodeAction.TriggerType> triggerCombo = new ComboBox<>();
+        triggerCombo.getItems().addAll(NodeAction.TriggerType.values());
+        triggerCombo.setValue(create ? NodeAction.TriggerType.ON_CHANGE : existing.getTriggerType());
+        triggerCombo.setMaxWidth(Double.MAX_VALUE);
+
+        TextField triggerValueField = new TextField(create ? "" : nullToEmpty(existing.getTriggerValue()));
+        triggerValueField.setPromptText("nur fuer ON_VALUE / ON_GREATER_THAN / ON_LESS_THAN");
+
+        TextField intervalField = new TextField(create ? "1000" : String.valueOf(existing.getIntervalMs()));
+        intervalField.setPromptText("ms fuer ON_INTERVAL");
+
+        CheckBox initEnabled = new CheckBox("Action-Initial-Script aktivieren");
+        initEnabled.setSelected(!create && existing.isInitEnabled());
+        JavaScriptEditorPane initEditor = new JavaScriptEditorPane(170);
+        initEditor.setText(create ? "" : nullToEmpty(existing.getInitScript()));
+        TitledPane initPane = new TitledPane("Action Init / Session", initEditor);
+        initPane.setExpanded(initEnabled.isSelected());
+        initPane.disableProperty().bind(initEnabled.selectedProperty().not());
+
+        CheckBox conditionEnabled = new CheckBox("Bedingung aktivieren");
+        conditionEnabled.setSelected(!create && existing.isConditionEnabled());
+        JavaScriptEditorPane conditionEditor = new JavaScriptEditorPane(170);
+        conditionEditor.setText(create ? "" : nullToEmpty(existing.getConditionScript()));
+        TitledPane conditionPane = new TitledPane("Condition JavaScript - letzter Ausdruck muss true/false sein", conditionEditor);
+        conditionPane.setExpanded(conditionEnabled.isSelected());
+        conditionPane.disableProperty().bind(conditionEnabled.selectedProperty().not());
+
+        JavaScriptEditorPane scriptEditor = new JavaScriptEditorPane(280);
+        scriptEditor.setText(create ? "" : nullToEmpty(existing.getScript()));
+
+        Label helperInfo = new Label("Auswahl erzeugt echten Code mit festen NodeIDs. Keine Variable haengt von Checkboxen zur Laufzeit ab.");
+        helperInfo.setWrapText(true);
+        HBox helperButtons = new HBox(8);
+        Button addReadNumber = new Button("Auswahl als var Number einfuegen");
+        Button addReadText = new Button("Auswahl als var Text einfuegen");
+        Button addWrite = new Button("Auswahl als opc.write einfuegen");
+        Button addConditionRead = new Button("Auswahl in Bedingung lesen");
+        helperButtons.getChildren().addAll(addReadNumber, addReadText, addWrite, addConditionRead);
+        helperButtons.setAlignment(Pos.CENTER_LEFT);
+
+        VBox templateBox = new VBox(6);
+        Label templateLabel = new Label("Templates aus Configuration");
+        templateLabel.setStyle("-fx-font-weight:bold;");
+        HBox templateButtons = new HBox(8);
+        templateButtons.setAlignment(Pos.CENTER_LEFT);
+        loadTemplateButtons(templateButtons, scriptEditor);
+        templateBox.getChildren().addAll(templateLabel, templateButtons);
+
+        addReadNumber.setOnAction(e -> scriptEditor.insertTextAtCaret(snippetFromSelected("readNumber", "")));
+        addReadText.setOnAction(e -> scriptEditor.insertTextAtCaret(snippetFromSelected("read", "")));
+        addWrite.setOnAction(e -> scriptEditor.insertTextAtCaret(snippetFromSelected("write", "result.value")));
+        addConditionRead.setOnAction(e -> conditionEditor.insertTextAtCaret(snippetFromSelected("readNumber", "")));
+
+        GridPane form = new GridPane();
+        form.setHgap(10);
+        form.setVgap(8);
+        form.add(new Label("Name"), 0, 0); form.add(nameField, 1, 0);
+        form.add(new Label("Trigger"), 0, 1); form.add(triggerCombo, 1, 1);
+        form.add(new Label("Trigger Value"), 0, 2); form.add(triggerValueField, 1, 2);
+        form.add(new Label("Interval ms"), 0, 3); form.add(intervalField, 1, 3);
+        GridPane.setHgrow(nameField, Priority.ALWAYS);
+        GridPane.setHgrow(triggerCombo, Priority.ALWAYS);
+        GridPane.setHgrow(triggerValueField, Priority.ALWAYS);
+        GridPane.setHgrow(intervalField, Priority.ALWAYS);
+
+        updateTriggerFields(triggerCombo.getValue(), triggerValueField, intervalField);
+        triggerCombo.valueProperty().addListener((obs, oldVal, newVal) -> updateTriggerFields(newVal, triggerValueField, intervalField));
+
+        main.getChildren().addAll(
+                form,
+                new Separator(),
+                helperInfo,
+                helperButtons,
+                templateBox,
+                initEnabled, initPane,
+                conditionEnabled, conditionPane,
+                new Label("Hauptscript"), scriptEditor
+        );
+        VBox.setVgrow(scriptEditor, Priority.ALWAYS);
+
+        dialog.getDialogPane().setContent(new ScrollPane(main));
+        dialog.getDialogPane().getButtonTypes().addAll(ButtonType.OK, ButtonType.CANCEL);
+
+        dialog.setResultConverter(buttonType -> {
+            if (buttonType != ButtonType.OK) return null;
+            String name = nullToEmpty(nameField.getText()).trim();
+            String script = nullToEmpty(scriptEditor.getText()).trim();
+            if (name.isEmpty()) { showAlert("Validation", "Name fehlt", "Bitte Action-Namen eingeben."); return null; }
+            if (script.isEmpty()) { showAlert("Validation", "Script fehlt", "Bitte JavaScript-Code eingeben."); return null; }
+
+            NodeAction action = new NodeAction();
+            action.setNodeId(triggerRow.getNodeId());
+            action.setActionName(name);
+            action.setTriggerType(triggerCombo.getValue());
+            action.setTriggerValue(triggerValueField.getText());
+            action.setScript(scriptEditor.getText());
+            action.setInitEnabled(initEnabled.isSelected());
+            action.setInitScript(initEditor.getText());
+            action.setConditionEnabled(conditionEnabled.isSelected());
+            action.setConditionScript(conditionEditor.getText());
+            action.setConditionNodeIds(List.of());
+            action.setNodeAliases(java.util.Map.of());
+            action.setEnabled(create || existing == null || existing.isEnabled());
+            try { action.setIntervalMs(Integer.parseInt(intervalField.getText())); }
+            catch (NumberFormatException ignored) { action.setIntervalMs(1000); }
+            return action;
+        });
+
+        Platform.runLater(nameField::requestFocus);
+        Optional<NodeAction> result = dialog.showAndWait();
+        return result.orElse(null);
+    }
+
+
+    private void loadTemplateButtons(HBox templateButtons, JavaScriptEditorPane scriptEditor) {
+        templateButtons.getChildren().clear();
+        try {
+            List<ScriptTemplate> templates = scriptTemplateService.load();
+            for (ScriptTemplate template : templates) {
+                if (template == null || !template.isEnabled()) continue;
+                Button button = new Button(template.getName());
+                button.setOnAction(e -> scriptEditor.insertTextAtCaret(snippetFromTemplate(template.getId())));
+                templateButtons.getChildren().add(button);
+            }
+            Button manage = new Button("Templates verwalten...");
+            manage.setOnAction(e -> showAlert("Templates", "Templates bearbeiten", "Unter Configuration → Script Templates koennen GET/POST/SET und eigene Templates bearbeitet werden."));
+            templateButtons.getChildren().add(manage);
+        } catch (Exception ex) {
+            Button fallback = new Button("Templates konnten nicht geladen werden");
+            fallback.setDisable(true);
+            templateButtons.getChildren().add(fallback);
+        }
+    }
+
+    private String snippetFromTemplate(String templateId) {
+        try {
+            return scriptTemplateService.render(templateId, selectedSpecs());
+        } catch (Exception ex) {
+            return "// Template Fehler: " + ex.getMessage() + "\n";
+        }
+    }
+
+    private List<ScriptSnippetBuilder.NodeSpec> selectedSpecs() {
+        List<ScriptSnippetBuilder.NodeSpec> specs = new ArrayList<>();
+        List<NodeRow> rows = monitoredNodesSupplier.get();
+        if (rows == null || rows.isEmpty()) return specs;
+        for (NodeRow row : rows) {
+            if (row == null || row.getNodeId() == null || row.getNodeId().isBlank()) continue;
+            specs.add(new ScriptSnippetBuilder.NodeSpec(row.getNodeId(), row.getDisplayName()));
+        }
+        return specs;
+    }
+
+    private String snippetFromSelected(String mode, String writeExpression) {
+        List<ScriptSnippetBuilder.NodeSpec> specs = selectedSpecs();
+        if (specs.isEmpty()) {
+            return "// Keine markierten Nodes vorhanden. NodeID direkt einsetzen:\n" +
+                    ("write".equals(mode)
+                            ? ScriptSnippetBuilder.write("ns=3;s=Node", writeExpression)
+                            : ScriptSnippetBuilder.read("ns=3;s=Node", "Node", true));
+        }
+        return ScriptSnippetBuilder.build(mode, specs, writeExpression);
+    }
+
+    private void updateTriggerFields(NodeAction.TriggerType type, TextField triggerValueField, TextField intervalField) {
+        boolean needsValue = type == NodeAction.TriggerType.ON_VALUE
+                || type == NodeAction.TriggerType.ON_GREATER_THAN
+                || type == NodeAction.TriggerType.ON_LESS_THAN;
+        triggerValueField.setDisable(!needsValue);
+        intervalField.setDisable(type != NodeAction.TriggerType.ON_INTERVAL);
+    }
+
+    private void testAction(NodeAction action, NodeRow nodeRow) {
+        String currentValue = nodeRow.getValue();
+        if (currentValue == null || currentValue.isEmpty()) currentValue = "test-value";
+        actionService.testAction(action.getNodeId(), action.getActionName(), currentValue);
+        showAlert("Action Test", "Testing: " + action.getActionName(), "Action queued with value: " + currentValue);
+    }
+
+    private String nullToEmpty(String s) { return s == null ? "" : s; }
+
+    private void showAlert(String title, String header, String content) {
+        Alert alert = new Alert(Alert.AlertType.INFORMATION);
+        alert.setTitle(title);
+        alert.setHeaderText(header);
+        alert.setContentText(content);
+        alert.showAndWait();
+    }
+}
diff --git a/src/main/java/de/opcua/app/ui/ConfigController.java b/src/main/java/de/opcua/app/ui/ConfigController.java
new file mode 100644
index 0000000..3d7aaf0
--- /dev/null
+++ b/src/main/java/de/opcua/app/ui/ConfigController.java
@@ -0,0 +1,401 @@
+package de.opcua.app.ui;
+
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.AppPaths;
+import de.opcua.app.config.ConfigSecurity;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.model.SystemInitScript;
+import de.opcua.app.model.ScriptTemplate;
+import de.opcua.app.service.SystemInitScriptService;
+import de.opcua.app.service.ScriptTemplateService;
+import javafx.event.ActionEvent;
+import javafx.fxml.FXML;
+import javafx.scene.control.*;
+import javafx.scene.layout.StackPane;
+import javafx.stage.FileChooser;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+public class ConfigController {
+
+  @FXML private TextField endpointTextBox;
+  @FXML private TextField hostTextBox;
+
+  @FXML private CheckBox httpEnabledCheckBox;
+  @FXML private TextField httpPortTextBox;
+
+  @FXML private CheckBox httpsEnabledCheckBox;
+  @FXML private TextField httpsPortTextBox;
+  @FXML private TextField keystorePathTextBox;
+  @FXML private PasswordField keystorePasswordTextBox;
+  @FXML private ComboBox<String> keystoreTypeComboBox;
+
+  @FXML private CheckBox systemInitEnabledCheckBox;
+  @FXML private CheckBox systemInitRunAtProgramStartCheckBox;
+  @FXML private CheckBox systemInitRunAfterConnectCheckBox;
+  @FXML private StackPane systemInitEditorHost;
+  @FXML private Label systemInitPathLabel;
+
+  @FXML private ListView<ScriptTemplate> templateListView;
+  @FXML private TextField templateNameField;
+  @FXML private CheckBox templateEnabledCheckBox;
+  @FXML private StackPane templateEditorHost;
+  @FXML private Label templatePathLabel;
+
+  @FXML private Label configDirectoryLabel;
+  @FXML private Label settingsPathLabel;
+  @FXML private CheckBox configEncryptionEnabledCheckBox;
+  @FXML private PasswordField configEncryptionPasswordField;
+  @FXML private CheckBox restAuthEnabledCheckBox;
+  @FXML private TextField restAuthUserTextBox;
+  @FXML private PasswordField restAuthPasswordField;
+
+  private Settings initial;
+  private Settings updated;
+  private final SettingsService settingsService = new SettingsService();
+  private final SystemInitScriptService systemInitScriptService = new SystemInitScriptService();
+  private final ScriptTemplateService scriptTemplateService = new ScriptTemplateService();
+  private JavaScriptEditorPane systemInitEditor;
+  private JavaScriptEditorPane templateEditor;
+  private boolean loadingTemplateSelection;
+  private Consumer<SystemInitScript> systemInitRunner;
+
+  public void setSettings(Settings s) {
+    this.initial = s;
+    if (endpointTextBox != null) endpointTextBox.setText(s.endpoint());
+    if (hostTextBox != null) hostTextBox.setText(s.host());
+    if (httpEnabledCheckBox != null) httpEnabledCheckBox.setSelected(s.httpEnabled());
+    if (httpPortTextBox != null) httpPortTextBox.setText(String.valueOf(s.httpPort()));
+    if (httpsEnabledCheckBox != null) httpsEnabledCheckBox.setSelected(s.httpsEnabled());
+    if (httpsPortTextBox != null) httpsPortTextBox.setText(String.valueOf(s.httpsPort()));
+    if (keystorePathTextBox != null) keystorePathTextBox.setText(s.keystorePath());
+    if (keystorePasswordTextBox != null) keystorePasswordTextBox.setText(s.keystorePassword());
+    if (keystoreTypeComboBox != null) keystoreTypeComboBox.setValue(s.keystoreType());
+    if (configDirectoryLabel != null) configDirectoryLabel.setText(AppPaths.configDirectory().toString());
+    if (settingsPathLabel != null) settingsPathLabel.setText(settingsService.getFile().toString());
+    if (configEncryptionEnabledCheckBox != null) configEncryptionEnabledCheckBox.setSelected(s.configEncryptionEnabled());
+    if (configEncryptionPasswordField != null) configEncryptionPasswordField.setText(s.configEncryptionPassword());
+    if (restAuthEnabledCheckBox != null) restAuthEnabledCheckBox.setSelected(s.restAuthEnabled());
+    if (restAuthUserTextBox != null) restAuthUserTextBox.setText(s.restAuthUser());
+    if (restAuthPasswordField != null) restAuthPasswordField.clear();
+    loadSystemInitScript();
+    loadScriptTemplates();
+  }
+
+  public void setSystemInitRunner(Consumer<SystemInitScript> systemInitRunner) {
+    this.systemInitRunner = systemInitRunner;
+  }
+
+  @FXML
+  public void initialize() {
+    if (keystoreTypeComboBox != null) {
+      keystoreTypeComboBox.getItems().addAll("JKS", "PKCS12");
+      keystoreTypeComboBox.setValue("JKS");
+    }
+    if (configDirectoryLabel != null) configDirectoryLabel.setText(AppPaths.configDirectory().toString());
+    if (settingsPathLabel != null) settingsPathLabel.setText(settingsService.getFile().toString());
+    systemInitEditor = new JavaScriptEditorPane(260);
+    if (systemInitEditorHost != null) {
+      systemInitEditorHost.getChildren().setAll(systemInitEditor);
+    }
+    if (systemInitPathLabel != null) {
+      systemInitPathLabel.setText(systemInitScriptService.getFilePath());
+    }
+    templateEditor = new JavaScriptEditorPane(260);
+    if (templateEditorHost != null) {
+      templateEditorHost.getChildren().setAll(templateEditor);
+    }
+    if (templatePathLabel != null) {
+      templatePathLabel.setText(scriptTemplateService.getFilePath());
+    }
+    setupTemplateList();
+    loadSystemInitScript();
+    loadScriptTemplates();
+  }
+
+  @FXML
+  public void SaveButton_Click(ActionEvent e) {
+    try {
+      int httpPort = Integer.parseInt(httpPortTextBox.getText());
+      int httpsPort = Integer.parseInt(httpsPortTextBox.getText());
+
+      Settings base = initial != null ? initial : Settings.defaults();
+      String newRestPassword = restAuthPasswordField != null ? restAuthPasswordField.getText() : "";
+      String restHash = (newRestPassword != null && !newRestPassword.isBlank())
+          ? ConfigSecurity.sha256(newRestPassword)
+          : base.restAuthPasswordHash();
+
+      updated = new Settings(
+          endpointTextBox.getText(),
+          hostTextBox.getText(),
+          httpEnabledCheckBox != null && httpEnabledCheckBox.isSelected(),
+          httpPort,
+          httpsEnabledCheckBox != null && httpsEnabledCheckBox.isSelected(),
+          httpsPort,
+          keystorePathTextBox != null ? keystorePathTextBox.getText() : "",
+          keystorePasswordTextBox != null ? keystorePasswordTextBox.getText() : "",
+          keystoreTypeComboBox != null ? keystoreTypeComboBox.getValue() : "JKS",
+          base.scriptLoggingEnabled(),
+          base.scriptLogLevel(),
+          base.scriptLogDirectory(),
+          configEncryptionEnabledCheckBox != null && configEncryptionEnabledCheckBox.isSelected(),
+          configEncryptionPasswordField != null ? configEncryptionPasswordField.getText() : "",
+          restAuthEnabledCheckBox != null && restAuthEnabledCheckBox.isSelected(),
+          restAuthUserTextBox != null && !restAuthUserTextBox.getText().isBlank() ? restAuthUserTextBox.getText() : "admin",
+          restHash
+      );
+
+      // Save settings first so following config writes already use the selected encryption state.
+      settingsService.save(updated);
+      saveSystemInitScript();
+      saveScriptTemplates();
+      endpointTextBox.getScene().getWindow().hide();
+    } catch (NumberFormatException ex) {
+      showError("Invalid port number", ex.getMessage());
+    } catch (IOException ex) {
+      showError("System Init speichern fehlgeschlagen", ex.getMessage());
+    }
+  }
+
+  @FXML
+  public void CancelButton_Click(ActionEvent e) {
+    endpointTextBox.getScene().getWindow().hide();
+  }
+
+  @FXML
+  public void RunSystemInit_Click(ActionEvent e) {
+    try {
+      SystemInitScript config = saveSystemInitScript();
+      if (systemInitRunner != null) systemInitRunner.accept(config);
+    } catch (IOException ex) {
+      showError("System Init speichern/ausfuehren fehlgeschlagen", ex.getMessage());
+    }
+  }
+
+  @FXML
+  public void InsertRegLoginTemplate_Click(ActionEvent e) {
+    if (systemInitEditor == null) return;
+    systemInitEditor.insertTextAtCaret("""
+var response = http.postJson("http://localhost:9000/api/reglogin", {
+  client: "opcua-client",
+  user: "opc",
+  password: "secret"
+});
+
+if (response.status < 200 || response.status >= 300) {
+  throw "RegLogin failed: HTTP " + response.status + " / " + response.body;
+}
+
+var result = JSON.parse(response.body);
+global.session = result;
+global.token = result.token;
+global.apiResult = result;
+log.info("RegLogin OK");
+""");
+  }
+
+
+  @FXML
+  public void NewTemplate_Click(ActionEvent e) {
+    if (templateListView == null) return;
+    ScriptTemplate current = templateListView.getSelectionModel().getSelectedItem();
+    if (current != null) commitTemplate(current);
+    ScriptTemplate template = new ScriptTemplate();
+    template.setName("Neues Template");
+    template.setEnabled(true);
+    template.setBuiltIn(false);
+    template.setScript("""
+// Eigenes Template
+// Platzhalter:
+// {{readNumberVars}}      -> var Name = Number(opc.read("ns=..."));
+// {{readTextVars}}        -> var Name = opc.read("ns=...");
+// {{payloadFields}}       -> JSON-Felder aus selektierten Nodes
+// {{opcWritesFromResult}} -> opc.write(...) fuer selektierte Nodes
+{{readNumberVars}}
+
+var response = http.postJson("http://localhost:9000/api/process", {
+{{payloadFields}}});
+
+var result = JSON.parse(response.body);
+global.apiResult = result;
+{{opcWritesFromResult}}
+""");
+    templateListView.getItems().add(template);
+    templateListView.getSelectionModel().select(template);
+  }
+
+  @FXML
+  public void DeleteTemplate_Click(ActionEvent e) {
+    if (templateListView == null) return;
+    ScriptTemplate selected = templateListView.getSelectionModel().getSelectedItem();
+    if (selected == null) return;
+    templateListView.getItems().remove(selected);
+    if (!templateListView.getItems().isEmpty()) {
+      templateListView.getSelectionModel().select(0);
+      showTemplate(templateListView.getSelectionModel().getSelectedItem());
+    } else clearTemplateForm();
+  }
+
+  @FXML
+  public void ResetTemplates_Click(ActionEvent e) {
+    Alert confirm = new Alert(Alert.AlertType.CONFIRMATION);
+    confirm.setTitle("Templates zuruecksetzen");
+    confirm.setHeaderText("Standard-Templates wiederherstellen?");
+    confirm.setContentText("Eigene Aenderungen in GET/POST/SET und eigene Templates werden ersetzt.");
+    if (confirm.showAndWait().orElse(ButtonType.CANCEL) != ButtonType.OK) return;
+    try {
+      List<ScriptTemplate> defaults = scriptTemplateService.resetDefaults();
+      setTemplateItems(defaults);
+    } catch (IOException ex) {
+      showError("Templates zuruecksetzen fehlgeschlagen", ex.getMessage());
+    }
+  }
+
+  @FXML
+  public void SaveTemplates_Click(ActionEvent e) {
+    try {
+      saveScriptTemplates();
+    } catch (IOException ex) {
+      showError("Templates speichern fehlgeschlagen", ex.getMessage());
+    }
+  }
+
+  @FXML
+  public void InsertTemplatePlaceholders_Click(ActionEvent e) {
+    if (templateEditor == null) return;
+    templateEditor.insertTextAtCaret("""
+
+// Verfuegbare Platzhalter:
+{{readNumberVars}}
+{{payloadFields}}
+{{opcWritesFromResult}}
+""");
+  }
+
+  @FXML
+  public void BrowseKeystore_Click(ActionEvent e) {
+    FileChooser fc = new FileChooser();
+    fc.setTitle("Select Keystore");
+    fc.getExtensionFilters().addAll(
+        new FileChooser.ExtensionFilter("Keystore Files", "*.jks", "*.p12", "*.pfx"),
+        new FileChooser.ExtensionFilter("All Files", "*.*")
+    );
+
+    File file = fc.showOpenDialog(keystorePathTextBox.getScene().getWindow());
+    if (file != null) keystorePathTextBox.setText(file.getAbsolutePath());
+  }
+
+  private void loadSystemInitScript() {
+    try {
+      SystemInitScript config = systemInitScriptService.load();
+      if (systemInitEnabledCheckBox != null) systemInitEnabledCheckBox.setSelected(config.isEnabled());
+      if (systemInitRunAtProgramStartCheckBox != null) systemInitRunAtProgramStartCheckBox.setSelected(config.isRunAtProgramStart());
+      if (systemInitRunAfterConnectCheckBox != null) systemInitRunAfterConnectCheckBox.setSelected(config.isRunAfterConnect());
+      if (systemInitEditor != null) systemInitEditor.setText(config.getScript());
+    } catch (Exception ex) {
+      // keep config window usable even if file is broken
+      if (systemInitEditor != null) systemInitEditor.setText("// System Init konnte nicht geladen werden: " + ex.getMessage());
+    }
+  }
+
+  private SystemInitScript saveSystemInitScript() throws IOException {
+    SystemInitScript config = systemInitScriptService.load();
+    config.setEnabled(systemInitEnabledCheckBox != null && systemInitEnabledCheckBox.isSelected());
+    config.setRunAtProgramStart(systemInitRunAtProgramStartCheckBox != null && systemInitRunAtProgramStartCheckBox.isSelected());
+    config.setRunAfterConnect(systemInitRunAfterConnectCheckBox == null || systemInitRunAfterConnectCheckBox.isSelected());
+    config.setScript(systemInitEditor != null ? systemInitEditor.getText() : "");
+    systemInitScriptService.save(config);
+    return config;
+  }
+
+
+  private void setupTemplateList() {
+    if (templateListView == null) return;
+    templateListView.setCellFactory(list -> new ListCell<>() {
+      @Override protected void updateItem(ScriptTemplate item, boolean empty) {
+        super.updateItem(item, empty);
+        if (empty || item == null) {
+          setText(null);
+        } else {
+          setText((item.isEnabled() ? "● " : "○ ") + item.getName() + (item.isBuiltIn() ? " · Standard" : ""));
+        }
+      }
+    });
+    templateListView.getSelectionModel().selectedItemProperty().addListener((obs, oldVal, newVal) -> {
+      if (loadingTemplateSelection) return;
+      if (oldVal != null) commitTemplate(oldVal);
+      showTemplate(newVal);
+    });
+  }
+
+  private void loadScriptTemplates() {
+    if (templateListView == null) return;
+    try {
+      setTemplateItems(scriptTemplateService.load());
+    } catch (Exception ex) {
+      showError("Templates laden fehlgeschlagen", ex.getMessage());
+    }
+  }
+
+  private void setTemplateItems(List<ScriptTemplate> templates) {
+    if (templateListView == null) return;
+    loadingTemplateSelection = true;
+    templateListView.getItems().setAll(templates == null ? List.of() : templates);
+    loadingTemplateSelection = false;
+    if (!templateListView.getItems().isEmpty()) {
+      templateListView.getSelectionModel().select(0);
+      showTemplate(templateListView.getSelectionModel().getSelectedItem());
+    } else clearTemplateForm();
+  }
+
+  private void showTemplate(ScriptTemplate template) {
+    if (template == null) { clearTemplateForm(); return; }
+    if (templateNameField != null) templateNameField.setText(template.getName());
+    if (templateEnabledCheckBox != null) templateEnabledCheckBox.setSelected(template.isEnabled());
+    if (templateEditor != null) templateEditor.setText(template.getScript() == null ? "" : template.getScript());
+  }
+
+  private void clearTemplateForm() {
+    if (templateNameField != null) templateNameField.clear();
+    if (templateEnabledCheckBox != null) templateEnabledCheckBox.setSelected(true);
+    if (templateEditor != null) templateEditor.setText("");
+  }
+
+  private void commitTemplate(ScriptTemplate template) {
+    if (template == null) return;
+    if (templateNameField != null) template.setName(templateNameField.getText());
+    if (templateEnabledCheckBox != null) template.setEnabled(templateEnabledCheckBox.isSelected());
+    if (templateEditor != null) template.setScript(templateEditor.getText());
+    template.setUpdatedAt(System.currentTimeMillis());
+  }
+
+  private List<ScriptTemplate> collectTemplates() {
+    if (templateListView == null) return List.of();
+    ScriptTemplate current = templateListView.getSelectionModel().getSelectedItem();
+    if (current != null) commitTemplate(current);
+    return new ArrayList<>(templateListView.getItems());
+  }
+
+  private void saveScriptTemplates() throws IOException {
+    if (templateListView == null) return;
+    List<ScriptTemplate> saved = scriptTemplateService.save(collectTemplates());
+    setTemplateItems(saved);
+  }
+
+  private void showError(String title, String message) {
+    Alert alert = new Alert(Alert.AlertType.ERROR);
+    alert.setTitle(title);
+    alert.setHeaderText(title);
+    alert.setContentText(message);
+    alert.showAndWait();
+  }
+
+  public Optional<Settings> getUpdatedSettings() {
+    return Optional.ofNullable(updated);
+  }
+}
diff --git a/src/main/java/de/opcua/app/ui/EditableValueCellFactory.java b/src/main/java/de/opcua/app/ui/EditableValueCellFactory.java
new file mode 100644
index 0000000..dd9aec1
--- /dev/null
+++ b/src/main/java/de/opcua/app/ui/EditableValueCellFactory.java
@@ -0,0 +1,193 @@
+package de.opcua.app.ui;
+
+import de.opcua.app.model.NodeRow;
+import de.opcua.app.opc.OpcUaService;
+import javafx.scene.control.*;
+import javafx.scene.control.cell.TextFieldTableCell;
+import javafx.util.StringConverter;
+
+/**
+ * Makes the Value column editable with OPC UA write-back
+ */
+public class EditableValueCellFactory {
+    
+    private final OpcUaService opcService;
+    
+    public EditableValueCellFactory(OpcUaService opcService) {
+        this.opcService = opcService;
+    }
+    
+    /**
+     * Create editable value column
+     */
+    public TableColumn<NodeRow, String> createEditableValueColumn() {
+        TableColumn<NodeRow, String> col = new TableColumn<>("Value");
+        col.setCellValueFactory(c -> c.getValue().valueProperty());
+        col.setCellFactory(tc -> new EditableValueCell());
+        col.setEditable(true);
+        col.setPrefWidth(150);
+        col.setOnEditCommit(event -> handleValueEdit(event));
+        
+        return col;
+    }
+    
+    private void handleValueEdit(TableColumn.CellEditEvent<NodeRow, String> event) {
+        NodeRow row = event.getRowValue();
+        String newValue = event.getNewValue();
+        String oldValue = event.getOldValue();
+        
+        if (newValue == null || newValue.equals(oldValue)) {
+            return;
+        }
+        
+        // Attempt to write to OPC UA
+        if (!opcService.isConnected()) {
+            showError("Not connected to OPC UA server");
+            row.setValue(oldValue); // Revert
+            return;
+        }
+        
+        if (!row.isReadable()) {
+            showError("Node is not writable");
+            row.setValue(oldValue); // Revert
+            return;
+        }
+        
+        // Write to OPC UA
+        opcService.writeValue(row.getNodeId(), newValue)
+            .thenAccept(success -> {
+                javafx.application.Platform.runLater(() -> {
+                    if (success) {
+                        row.setValue(newValue);
+                        System.out.println("[OPC UA] Write successful: " + row.getNodeId() + " = " + newValue);
+                    } else {
+                        showError("Write failed for " + row.getNodeId());
+                        row.setValue(oldValue); // Revert
+                    }
+                });
+            })
+            .exceptionally(ex -> {
+                javafx.application.Platform.runLater(() -> {
+                    showError("Write error: " + ex.getMessage());
+                    row.setValue(oldValue); // Revert
+                });
+                return null;
+            });
+    }
+    
+    private void showError(String message) {
+        Alert alert = new Alert(Alert.AlertType.ERROR);
+        alert.setTitle("Write Error");
+        alert.setHeaderText("Failed to write value");
+        alert.setContentText(message);
+        alert.show();
+    }
+    
+    /**
+     * Custom editable cell with visual feedback
+     */
+    private class EditableValueCell extends TableCell<NodeRow, String> {
+        private TextField textField;
+        
+        public EditableValueCell() {
+            setConverter(new StringConverter<String>() {
+                @Override
+                public String toString(String object) {
+                    return object == null ? "" : object;
+                }
+                
+                @Override
+                public String fromString(String string) {
+                    return string;
+                }
+            });
+        }
+        
+        @Override
+        public void startEdit() {
+            NodeRow row = getTableRow().getItem();
+            if (row == null || !row.isReadable()) {
+                // Not editable - show tooltip
+                Tooltip tooltip = new Tooltip("This node is read-only");
+                setTooltip(tooltip);
+                return;
+            }
+            
+            if (!opcService.isConnected()) {
+                Tooltip tooltip = new Tooltip("Not connected to OPC UA");
+                setTooltip(tooltip);
+                return;
+            }
+            
+            super.startEdit();
+            
+            if (textField == null) {
+                createTextField();
+            }
+            
+            textField.setText(getItem());
+            setText(null);
+            setGraphic(textField);
+            textField.selectAll();
+            textField.requestFocus();
+        }
+        
+        @Override
+        public void cancelEdit() {
+            super.cancelEdit();
+            setText(getItem());
+            setGraphic(null);
+        }
+        
+        @Override
+        protected void updateItem(String item, boolean empty) {
+            super.updateItem(item, empty);
+            
+            if (empty) {
+                setText(null);
+                setGraphic(null);
+                setStyle("");
+            } else {
+                if (isEditing()) {
+                    if (textField != null) {
+                        textField.setText(getItem());
+                    }
+                    setText(null);
+                    setGraphic(textField);
+                } else {
+                    setText(item);
+                    setGraphic(null);
+                    
+                    // Visual indication of editability
+                    NodeRow row = getTableRow().getItem();
+                    if (row != null && row.isReadable() && opcService.isConnected()) {
+                        setStyle("-fx-background-color: #f0fff0;"); // Light green
+                        setTooltip(new Tooltip("Double-click to edit"));
+                    } else {
+                        setStyle("");
+                        setTooltip(null);
+                    }
+                }
+            }
+        }
+        
+        private void createTextField() {
+            textField = new TextField(getItem());
+            textField.setMinWidth(getWidth() - getGraphicTextGap() * 2);
+            
+            textField.setOnAction(event -> {
+                commitEdit(textField.getText());
+            });
+            
+            textField.focusedProperty().addListener((obs, wasFocused, isNowFocused) -> {
+                if (!isNowFocused) {
+                    commitEdit(textField.getText());
+                }
+            });
+        }
+        
+        private void setConverter(StringConverter<String> converter) {
+            // Helper method for future enhancements
+        }
+    }
+}
diff --git a/src/main/java/de/opcua/app/ui/JavaScriptEditorPane.java b/src/main/java/de/opcua/app/ui/JavaScriptEditorPane.java
new file mode 100644
index 0000000..f1d0f59
--- /dev/null
+++ b/src/main/java/de/opcua/app/ui/JavaScriptEditorPane.java
@@ -0,0 +1,100 @@
+package de.opcua.app.ui;
+
+import javafx.scene.control.Button;
+import javafx.scene.control.Label;
+import javafx.scene.layout.BorderPane;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.Priority;
+import javafx.scene.layout.VBox;
+import org.fxmisc.flowless.VirtualizedScrollPane;
+import org.fxmisc.richtext.CodeArea;
+import org.fxmisc.richtext.LineNumberFactory;
+import org.fxmisc.richtext.model.StyleSpans;
+import org.fxmisc.richtext.model.StyleSpansBuilder;
+
+import java.time.Duration;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/** Lightweight JavaScript editor for JavaFX dialogs. */
+public class JavaScriptEditorPane extends BorderPane {
+    private static final String[] KEYWORDS = new String[] {
+            "break", "case", "catch", "class", "const", "continue", "debugger", "default", "delete", "do",
+            "else", "export", "extends", "finally", "for", "function", "if", "import", "in", "instanceof",
+            "let", "new", "return", "super", "switch", "this", "throw", "try", "typeof", "var", "void",
+            "while", "with", "yield", "true", "false", "null", "undefined"
+    };
+
+    private static final String KEYWORD_PATTERN = "\\b(" + String.join("|", KEYWORDS) + ")\\b";
+    private static final String STRING_PATTERN = "\"([^\"\\\\]|\\\\.)*\"|'([^'\\\\]|\\\\.)*'";
+    private static final String COMMENT_PATTERN = "//[^\\n]*|/\\*(.|\\R)*?\\*/";
+    private static final Pattern PATTERN = Pattern.compile(
+            "(?<KEYWORD>" + KEYWORD_PATTERN + ")"
+                    + "|(?<STRING>" + STRING_PATTERN + ")"
+                    + "|(?<COMMENT>" + COMMENT_PATTERN + ")"
+    );
+
+    private final CodeArea codeArea = new CodeArea();
+
+    public JavaScriptEditorPane() {
+        this(260);
+    }
+
+    public JavaScriptEditorPane(double prefHeight) {
+        getStyleClass().add("js-editor-pane");
+        codeArea.getStyleClass().add("js-code-area");
+        codeArea.setParagraphGraphicFactory(LineNumberFactory.get(codeArea));
+        codeArea.setWrapText(false);
+        codeArea.setPrefHeight(prefHeight);
+        codeArea.multiPlainChanges()
+                .successionEnds(Duration.ofMillis(120))
+                .subscribe(ignore -> codeArea.setStyleSpans(0, computeHighlighting(codeArea.getText())));
+
+        Button formatHint = new Button("JS");
+        formatHint.setDisable(true);
+        Label hint = new Label("GraalVM JavaScript · opc.read(...) · opc.write(...)");
+        HBox header = new HBox(8, formatHint, hint);
+        header.getStyleClass().add("js-editor-header");
+
+        VirtualizedScrollPane<CodeArea> scroll = new VirtualizedScrollPane<>(codeArea);
+        VBox.setVgrow(scroll, Priority.ALWAYS);
+        setTop(header);
+        setCenter(scroll);
+    }
+
+    public void setText(String text) {
+        codeArea.replaceText(text == null ? "" : text);
+        codeArea.setStyleSpans(0, computeHighlighting(codeArea.getText()));
+    }
+
+    public String getText() {
+        return codeArea.getText();
+    }
+
+    public void insertTextAtCaret(String text) {
+        codeArea.insertText(codeArea.getCaretPosition(), text == null ? "" : text);
+        codeArea.requestFocus();
+    }
+
+    public CodeArea getCodeArea() {
+        return codeArea;
+    }
+
+    private static StyleSpans<Collection<String>> computeHighlighting(String text) {
+        Matcher matcher = PATTERN.matcher(text == null ? "" : text);
+        int lastKwEnd = 0;
+        StyleSpansBuilder<Collection<String>> spansBuilder = new StyleSpansBuilder<>();
+        while (matcher.find()) {
+            String styleClass = matcher.group("KEYWORD") != null ? "keyword" :
+                    matcher.group("STRING") != null ? "string" :
+                            matcher.group("COMMENT") != null ? "comment" : null;
+            spansBuilder.add(Collections.emptyList(), matcher.start() - lastKwEnd);
+            spansBuilder.add(Collections.singleton(styleClass), matcher.end() - matcher.start());
+            lastKwEnd = matcher.end();
+        }
+        spansBuilder.add(Collections.emptyList(), (text == null ? 0 : text.length()) - lastKwEnd);
+        return spansBuilder.create();
+    }
+}
diff --git a/src/main/java/de/opcua/app/ui/MainController.java b/src/main/java/de/opcua/app/ui/MainController.java
new file mode 100644
index 0000000..282e652
--- /dev/null
+++ b/src/main/java/de/opcua/app/ui/MainController.java
@@ -0,0 +1,841 @@
+package de.opcua.app.ui;
+
+import de.opcua.app.config.Settings;
+import de.opcua.app.config.SettingsService;
+import de.opcua.app.model.NodeRow;
+import de.opcua.app.model.TreeNodeRef;
+import de.opcua.app.model.NodeAction;
+import de.opcua.app.model.SystemInitScript;
+import de.opcua.app.opc.OpcUaService;
+import de.opcua.app.scripting.ScriptService;
+import de.opcua.app.scripting.Store;
+import de.opcua.app.service.ActionService;
+import de.opcua.app.service.ActionPersistenceService;
+import de.opcua.app.service.SystemInitScriptService;
+import de.opcua.app.rest.OpcUaRestApi;
+import javafx.animation.KeyFrame;
+import javafx.animation.Timeline;
+import javafx.application.Platform;
+import javafx.collections.*;
+import javafx.event.ActionEvent;
+import javafx.fxml.FXML;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Scene;
+import javafx.scene.control.*;
+import javafx.scene.control.cell.CheckBoxTableCell;
+import javafx.scene.layout.Pane;
+import javafx.stage.Modality;
+import javafx.stage.Stage;
+import javafx.util.Duration;
+
+import java.io.IOException;
+import java.util.Optional;
+import java.util.function.Consumer;
+import java.util.List;
+import java.util.Map;
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+public class MainController {
+
+    @FXML private Button connectButton;
+    @FXML private Button saveButton;
+    @FXML private Button settingsButton;
+
+    @FXML private TreeView<TreeNodeRef> myTreeView;
+    @FXML private TableView<NodeRow> nodeListview;
+
+    @FXML private TableColumn<NodeRow, Boolean> checkBoxColumn;
+    @FXML private TableColumn<NodeRow, String> colDisplayName;
+    @FXML private TableColumn<NodeRow, String> colNodeType;
+    @FXML private TableColumn<NodeRow, String> colNodeId;
+    @FXML private TableColumn<NodeRow, String> colNamespaceIndex;
+    @FXML private TableColumn<NodeRow, String> colIdentifierType;
+    @FXML private TableColumn<NodeRow, String> colValue;
+
+    @FXML private TextArea logArea;
+    @FXML private TextField scriptField;
+    @FXML private Button runScriptButton;
+
+    private final ObservableList<NodeRow> rows = FXCollections.observableArrayList();
+
+    private final SettingsService settingsService = new SettingsService();
+    private Settings settings;
+
+    private final OpcUaService opc = new OpcUaService();
+    private final Store store = new Store();
+    private ActionService actionService;
+    private ActionButtonHelper actionButtonHelper;
+    private ActionPersistenceService actionPersistence;
+    private final SystemInitScriptService systemInitScripts = new SystemInitScriptService();
+    private OpcUaRestApi restApi;
+
+    private ScriptService scriptService;
+    private Timeline refreshTimer;
+
+    // ------------------------------------------------------------
+    // INIT
+    // ------------------------------------------------------------
+
+    @FXML
+    public void initialize() {
+        // KEIN try/catch → load() wirft keine IOException
+        settings = settingsService.load();
+
+        checkBoxColumn.setCellValueFactory(c -> c.getValue().selectedProperty());
+        checkBoxColumn.setCellFactory(CheckBoxTableCell.forTableColumn(checkBoxColumn));
+
+        colDisplayName.setCellValueFactory(c -> c.getValue().displayNameProperty());
+        colNodeType.setCellValueFactory(c -> c.getValue().nodeTypeProperty());
+        colNodeId.setCellValueFactory(c -> c.getValue().nodeIdProperty());
+        colNamespaceIndex.setCellValueFactory(c -> c.getValue().namespaceIndexProperty());
+        colIdentifierType.setCellValueFactory(c -> c.getValue().identifierTypeProperty());
+        
+        // ✅ Make value column EDITABLE
+        colValue.setCellValueFactory(c -> c.getValue().valueProperty());
+        colValue.setCellFactory(tc -> new EditableValueCell());
+        colValue.setEditable(true);
+        colValue.setOnEditCommit(event -> handleValueEdit(event));
+
+        nodeListview.setItems(rows);
+        nodeListview.getSelectionModel().setSelectionMode(SelectionMode.SINGLE);
+        nodeListview.setEditable(true);  // ✅ Table must be editable
+        checkBoxColumn.setEditable(true);
+
+        // ✅ Initialize ActionService and add Action Button Column
+        actionService = new ActionService(opc, store);
+        actionButtonHelper = new ActionButtonHelper(actionService, () -> rows.stream()
+                .filter(NodeRow::isSelected)
+                .collect(Collectors.toList()));
+        
+        // Add the action button column to the table
+        TableColumn<NodeRow, Void> actionColumn = actionButtonHelper.createActionColumn();
+        nodeListview.getColumns().add(actionColumn);
+        
+        // ✅ Add DELETE button column
+        TableColumn<NodeRow, Void> deleteColumn = createDeleteColumn();
+        nodeListview.getColumns().add(deleteColumn);
+        
+        // ✅ Initialize persistence and load saved actions
+        actionPersistence = new ActionPersistenceService();
+        java.util.Map<String, java.util.List<NodeAction>> savedActions = actionPersistence.loadActions();
+        if (!savedActions.isEmpty()) {
+            actionService.importActionsFromList(savedActions);
+            log("Loaded " + savedActions.size() + " saved node configurations with actions");
+
+            // Initial-Scripts sofort beim Programmstart versuchen.
+            // Wenn ein Script OPC-UA benötigt und der Client noch nicht verbunden ist,
+            // wird es beim Connect-Klick erneut ausgeführt.
+            actionService.initializeAllActionsAsync("program-start", false)
+                    .whenComplete((summary, ex) -> Platform.runLater(() -> {
+                        if (ex != null) {
+                            log("Initial scripts at program start failed: " + ex.getMessage());
+                        } else {
+                            log("Initial scripts at program start: " + summary);
+                        }
+                    }));
+        }
+        
+        // Globales System-Init-Script optional beim Programmstart ausführen.
+        runSystemInitIfConfigured("program-start", false, false);
+
+        // ✅ Start auto-save (every 60 seconds)
+        actionPersistence.startAutoSave(actionService, 60);
+        log("Action buttons enabled - Auto-save active (every 60s)");
+        
+        // ✅ Start REST API - IMMEDIATELY in initialize (not deferred)
+        log("═══════════════════════════════════");
+        log("Starting HTTP API...");
+        log("═══════════════════════════════════");
+        
+        try {
+            if (!settings.httpEnabled()) {
+                log("HTTP disabled in settings.");
+            } else {
+                int port = settings.httpPort();
+                
+                log("HTTP Port from settings: " + port);
+                
+                log("Creating OpcUaRestApi on port " + port + "...");
+                restApi = new OpcUaRestApi(opc, port, actionService);
+                log("OpcUaRestApi instance created");
+                
+                log("Calling restApi.start()...");
+                restApi.start();
+                log("restApi.start() completed");
+                
+                log("✅✅✅ HTTP API STARTED SUCCESSFULLY! ✅✅✅");
+                log("🌐 Web Interface: http://localhost:" + port + "/");
+                log("📡 API Status: http://localhost:" + port + "/api/status");
+                log("═══════════════════════════════════");
+                
+                // Also print to console
+                System.out.println("\n\n");
+                System.out.println("╔═══════════════════════════════════════════╗");
+                System.out.println("║     🚀 HTTP API STARTED SUCCESSFULLY      ║");
+                System.out.println("╠═══════════════════════════════════════════╣");
+                System.out.println("║  Port: " + port + "                                  ║");
+                System.out.println("║  Web UI: http://localhost:" + port + "/           ║");
+                System.out.println("╚═══════════════════════════════════════════╝");
+               
+    
+
+            }
+            
+        } catch (Exception e) {
+            log("❌❌❌ HTTP API START FAILED! ❌❌❌");
+            log("Error type: " + e.getClass().getName());
+            log("Error message: " + e.getMessage());
+            
+            System.err.println("\n\n");
+            System.err.println("╔═══════════════════════════════════════════╗");
+            System.err.println("║     ❌ HTTP API START FAILED!             ║");
+            System.err.println("╚═══════════════════════════════════════════╝");
+            System.err.println("Error: " + e.getMessage());
+            System.err.println("\nFull stack trace:");
+            e.printStackTrace();
+            System.err.println("\n\n");
+        }
+
+        initScripting();
+        startRefreshTimer();
+
+        log("Loaded settings. Endpoint=" + settings.endpoint());
+    }
+
+    // ------------------------------------------------------------
+    // CONNECT / DISCONNECT
+    // ------------------------------------------------------------
+
+    @FXML
+    public void connectButton_Click(ActionEvent e) {
+        if (opc.isConnected()) {
+            doDisconnect();
+        } else {
+doConnect();
+    }
+
+    }
+
+    @FXML
+    public void onSave(ActionEvent event) {
+        log("Save clicked. Selected rows: " + rows.size());
+    }
+
+    @FXML
+    public void onSettings(ActionEvent event) {
+        try {
+            FXMLLoader loader =
+                    new FXMLLoader(getClass().getResource("/ui/config.fxml"));
+            Pane root = loader.load();   // ← IOException MUSS hier gefangen werden
+
+            ConfigController controller = loader.getController();
+            controller.setSettings(settings);
+            controller.setSystemInitRunner(config -> runSystemInitFromConfiguration(config));
+
+            Stage dlg = new Stage();
+            dlg.setTitle("Configuration");
+            dlg.initModality(Modality.APPLICATION_MODAL);
+            dlg.setScene(new Scene(root, 980, 760));
+            dlg.showAndWait();
+
+        controller.getUpdatedSettings().ifPresent(s -> {
+    try {
+        settings = s;
+        settingsService.save(settings);
+        log("Settings saved. Endpoint=" + settings.endpoint());
+    } catch (IOException ex) {
+        alert("Fehler beim Speichern", ex.getMessage());
+    }
+});
+
+
+        } catch (IOException ex) {
+            alert("Settings Fehler", ex.getMessage());
+        }
+    }
+
+
+    private void runSystemInitFromConfiguration(SystemInitScript config) {
+        if (config == null || !config.isEnabled() || config.getScript() == null || config.getScript().isBlank()) {
+            log("System init from Configuration skipped: disabled or empty");
+            return;
+        }
+        actionService.executeSystemInitScriptAsync(config.getScript(), "configuration-manual", true)
+                .whenComplete((summary, ex) -> Platform.runLater(() -> {
+                    if (ex != null) {
+                        log("System init from Configuration failed: " + ex.getMessage());
+                    } else {
+                        log("System init from Configuration: " + summary);
+                    }
+                }));
+    }
+
+
+private void doConnect() {
+    connectButton.setDisable(true);
+    log("Connecting to " + settings.endpoint() + " ...");
+            System.err.println("Connecting to " + settings.endpoint() + " ...");
+
+    // ✅ opc.connect() selbst auf Background-Thread auslagern
+    CompletableFuture.supplyAsync(() -> opc.connect(settings.endpoint()))
+        .thenCompose(future -> future)  // unwrap das innere CompletableFuture
+        .whenCompleteAsync((v, ex) -> {
+            Platform.runLater(() -> {
+                connectButton.setDisable(false);
+
+                if (ex != null) {
+                    log("Connect failed: " + ex.getMessage());
+                    
+                    alert("Connect fehlgeschlagen", ex.toString());
+                } else {
+                    connectButton.setText("Disconnect");
+                    log("Connected.");
+                    System.err.println("Connected");
+
+                    // Erst globales RegLogin/System-Init ausführen, danach Action-Init.
+                    // Damit steht z. B. global.session vor Event-Scripts zur Verfügung.
+                    runSystemInitIfConfiguredThen("connect-click", true, true, () ->
+                            actionService.initializeAllActionsAsync("connect-click", true)
+                                    .whenComplete((summary, initEx) -> Platform.runLater(() -> {
+                                        if (initEx != null) {
+                                            log("Initial scripts after connect failed: " + initEx.getMessage());
+                                        } else {
+                                            log("Initial scripts after connect: " + summary);
+                                        }
+                                        loadOpcTree();
+                                        buildDigitalTwinInBackground();
+                                    }))
+                    );
+                }
+            });
+        });
+}
+
+    private void runSystemInitIfConfigured(String reason, boolean afterConnect, boolean resetSession) {
+        runSystemInitIfConfiguredThen(reason, afterConnect, resetSession, null);
+    }
+
+    private void runSystemInitIfConfiguredThen(String reason, boolean afterConnect, boolean resetSession, Runnable next) {
+        try {
+            SystemInitScript config = systemInitScripts.load();
+            boolean shouldRun = config.isEnabled()
+                    && !config.getScript().isBlank()
+                    && (afterConnect ? config.isRunAfterConnect() : config.isRunAtProgramStart());
+
+            if (!shouldRun) {
+                log("System init skipped: " + reason);
+                if (next != null) next.run();
+                return;
+            }
+
+            actionService.executeSystemInitScriptAsync(config.getScript(), reason, resetSession)
+                    .whenComplete((summary, ex) -> Platform.runLater(() -> {
+                        if (ex != null) {
+                            log("System init failed (" + reason + "): " + ex.getMessage());
+                        } else {
+                            log("System init " + reason + ": " + summary);
+                        }
+                        if (next != null) next.run();
+                    }));
+        } catch (Exception e) {
+            log("System init load failed: " + e.getMessage());
+            if (next != null) next.run();
+        }
+    }
+
+    /**
+     * Build complete OPC UA tree in background and cache it for API
+     */
+  
+   private void buildDigitalTwinInBackground() {
+    log("🔄 Building digital twin...");
+    
+    if (restApi != null) {
+        restApi.triggerDigitalTwinBuild();  // ✅ RestApi baut selbst, cached selbst
+        log("Digital twin build triggered via RestApi");
+        System.err.println("Digital twin build triggered via RestApi");
+
+        
+    } else {
+        log("⚠️ restApi is null - skipping");
+         System.err.println("restApi is null - skipping");
+
+    }
+}  
+    /**
+     * Browse OPC UA tree recursively for digital twin
+     */
+ private List<Map<String, Object>> browseTreeRecursive(String nodeId, int depth, int maxDepth) 
+        throws Exception {
+    if (depth >= maxDepth) return new ArrayList<>();
+
+    var childrenFuture = nodeId == null 
+        ? opc.browseRoot()
+        : opc.browse(nodeId);
+    
+    var children = childrenFuture.get(30, TimeUnit.SECONDS);
+    List<Map<String, Object>> result = new ArrayList<>();
+
+    for (var child : children) {
+        Map<String, Object> node = new HashMap<>();
+        
+        // ✅ Gleiche Keys wie OpcUaRestApi.browseRecursive()
+        node.put("nodeId",      child.nodeId());
+        node.put("displayName", child.displayName());
+        node.put("browseName",  child.browseName());
+        node.put("nodeClass",   child.nodeClass());
+        node.put("dataType",    child.dataType());
+        node.put("accessLevel", child.accessLevel());
+
+        // ✅ Wert nur für Variables lesen
+        if ("Variable".equals(child.nodeClass())) {
+            try {
+                String val = opc.readValue(child.nodeId()).get(5, TimeUnit.SECONDS);
+                node.put("value", val);
+            } catch (Exception e) {
+                node.put("value", null);
+            }
+        }
+
+        node.put("children", browseTreeRecursive(child.nodeId(), depth + 1, maxDepth));
+        result.add(node);
+    }
+    return result;
+}    
+    /**
+     * Count total nodes in tree
+     */
+    private int countTreeNodes(List<Map<String, Object>> tree) {
+        int count = tree.size();
+        for (var node : tree) {
+            @SuppressWarnings("unchecked")
+            List<Map<String, Object>> children = (List<Map<String, Object>>) node.get("children");
+            if (children != null && !children.isEmpty()) {
+                count += countTreeNodes(children);
+            }
+        }
+        return count;
+    }
+
+    private void doDisconnect() {
+        opc.disconnect();
+        myTreeView.setRoot(null);
+        connectButton.setText("Connect");
+        log("Disconnected.");
+    }
+
+    // ------------------------------------------------------------
+    // OPC UA TREE – ROOT + LAZY LOAD
+    // ------------------------------------------------------------
+
+    private void loadOpcTree() {
+        TreeItem<TreeNodeRef> uiRoot =
+                new TreeItem<>(new TreeNodeRef("OPC UA Server", ""));
+        uiRoot.setExpanded(true);
+        myTreeView.setRoot(uiRoot);
+
+        opc.browseRoot().whenComplete((roots, ex) ->
+            Platform.runLater(() -> {
+                if (ex != null) {
+                    log("Root browse error: " + ex.getMessage());
+                    return;
+                }
+
+                for (TreeNodeRef ref : roots) {
+                    TreeItem<TreeNodeRef> child = new TreeItem<>(ref);
+                    attachLazyLoader(child);
+                    uiRoot.getChildren().add(child);
+                }
+            })
+        );
+    }
+
+    private void attachLazyLoader(TreeItem<TreeNodeRef> item) {
+        item.getChildren().add(new TreeItem<>());
+
+        item.addEventHandler(TreeItem.branchExpandedEvent(), evt -> {
+
+            if (item.getChildren().size() != 1 ||
+                item.getChildren().get(0).getValue() != null) return;
+
+            item.getChildren().clear();
+
+            opc.browse(item.getValue().nodeId())
+               .whenComplete((children, ex) ->
+                   Platform.runLater(() -> {
+                       if (ex != null) {
+                           log("Browse error: " + ex.getMessage());
+                           return;
+                       }
+
+                       for (TreeNodeRef ref : children) {
+                           TreeItem<TreeNodeRef> child = new TreeItem<>(ref);
+                           attachLazyLoader(child);
+                           item.getChildren().add(child);
+                       }
+                   })
+               );
+        });
+    }
+
+    // ------------------------------------------------------------
+    // TREE → TABLE
+    // ------------------------------------------------------------
+
+    @FXML
+    public void myTreeView_AfterSelect() {
+        TreeItem<TreeNodeRef> item =
+                myTreeView.getSelectionModel().getSelectedItem();
+        if (item == null || item.getValue() == null) return;
+
+        TreeNodeRef ref = item.getValue();
+
+        if (rows.stream().anyMatch(r -> r.getNodeId().equals(ref.nodeId()))) return;
+
+        // ✅ Parse NodeId to extract namespace and identifier type
+        String namespaceIndex = "";
+        String identifierType = "";
+        
+        try {
+            org.eclipse.milo.opcua.stack.core.types.builtin.NodeId nid = 
+                org.eclipse.milo.opcua.stack.core.types.builtin.NodeId.parse(ref.nodeId());
+            
+            namespaceIndex = String.valueOf(nid.getNamespaceIndex());
+            
+            Object identifier = nid.getIdentifier();
+            if (identifier instanceof String) {
+                identifierType = "String";
+            } else if (identifier instanceof org.eclipse.milo.opcua.stack.core.types.builtin.unsigned.UInteger) {
+                identifierType = "UInteger";
+            } else if (identifier instanceof java.util.UUID) {
+                identifierType = "UUID";
+            } else if (identifier instanceof org.eclipse.milo.opcua.stack.core.types.builtin.ByteString) {
+                identifierType = "ByteString";
+            } else {
+                identifierType = identifier != null ? identifier.getClass().getSimpleName() : "Unknown";
+            }
+            
+            log("Parsed: ns=" + namespaceIndex + ", type=" + identifierType);
+            
+        } catch (Exception e) {
+            log("Could not parse NodeId: " + e.getMessage());
+        }
+
+        rows.add(new NodeRow(
+                true,
+                ref.displayName(),
+                "Variable",
+                ref.nodeId(),
+                namespaceIndex,    // ✅ Filled
+                identifierType,    // ✅ Filled
+                ""
+        ));
+
+        log("Added node: " + ref.nodeId());
+    }
+
+    // ------------------------------------------------------------
+    // SCRIPTING
+    // ------------------------------------------------------------
+
+    private void initScripting() {
+        scriptService = new ScriptService();
+
+        if (!scriptService.isAvailable()) {
+            runScriptButton.setDisable(true);
+            scriptField.setDisable(true);
+            log("Scripting deaktiviert");
+            return;
+        }
+
+        scriptService.put("store", store);
+        scriptService.put("settings", settings);
+        scriptService.put("opc", new JsOpcBridge(opc));
+        scriptService.put("log",
+                (Consumer<Object>) msg -> Platform.runLater(() -> log(String.valueOf(msg))));
+
+        log("Scripting aktiviert.");
+    }
+
+    @FXML
+    public void runScript(ActionEvent e) {
+        if (scriptService == null || !scriptService.isAvailable()) return;
+
+        String code = Optional.ofNullable(scriptField.getText()).orElse("").trim();
+        if (code.isEmpty()) return;
+
+        try {
+            Object result = scriptService.eval(code);
+            log("JS => " + result);
+        } catch (Exception ex) {
+            log("JS error: " + ex.getMessage());
+        }
+    }
+
+    // ------------------------------------------------------------
+    // REFRESH
+    // ------------------------------------------------------------
+
+    private void startRefreshTimer() {
+        refreshTimer =
+                new Timeline(new KeyFrame(Duration.seconds(1), e -> refreshTick()));
+        refreshTimer.setCycleCount(Timeline.INDEFINITE);
+        refreshTimer.play();
+    }
+
+private void refreshTick() {
+    for (NodeRow r : rows) {
+
+        if (!r.isSelected()) continue;
+        if (!r.isReadable()) continue;
+
+        String oldValue = r.getValue();
+        
+        opc.readValue(r.getNodeId())
+           .whenComplete((val, ex) ->
+               Platform.runLater(() -> {
+                   String newValue = (ex != null ? "<err>" : val);
+                   r.setValue(newValue);
+                   
+                   // ✅ Trigger actions on value change
+                   if (actionService != null && !newValue.equals(oldValue)) {
+                       actionService.processValueChange(r.getNodeId(), newValue);
+                   }
+               }));
+    }
+}
+
+
+
+
+    // ------------------------------------------------------------
+    // HELPERS
+    // ------------------------------------------------------------
+
+    private void log(String s) {
+        logArea.appendText(s + "\n");
+    }
+
+    private void alert(String title, String msg) {
+        Alert a = new Alert(Alert.AlertType.INFORMATION);
+        a.setTitle(title);
+        a.setHeaderText(title);
+        a.setContentText(msg);
+        a.showAndWait();
+    }
+    
+    // ------------------------------------------------------------
+    // DELETE COLUMN
+    // ------------------------------------------------------------
+    
+    private TableColumn<NodeRow, Void> createDeleteColumn() {
+        TableColumn<NodeRow, Void> deleteCol = new TableColumn<>("×");
+        deleteCol.setPrefWidth(50);
+        deleteCol.setMaxWidth(50);
+        deleteCol.setMinWidth(50);
+        deleteCol.setResizable(false);
+        
+        deleteCol.setCellFactory(col -> new TableCell<NodeRow, Void>() {
+            private final Button deleteButton = new Button("×");
+            
+            {
+                deleteButton.setStyle(
+                    "-fx-background-color: transparent; " +
+                    "-fx-text-fill: #ff3b30; " +
+                    "-fx-font-size: 18px; " +
+                    "-fx-font-weight: bold; " +
+                    "-fx-cursor: hand; " +
+                    "-fx-padding: 2px 8px;"
+                );
+                
+                deleteButton.setOnMouseEntered(e -> 
+                    deleteButton.setStyle(
+                        "-fx-background-color: rgba(255, 59, 48, 0.1); " +
+                        "-fx-text-fill: #ff3b30; " +
+                        "-fx-font-size: 18px; " +
+                        "-fx-font-weight: bold; " +
+                        "-fx-cursor: hand; " +
+                        "-fx-padding: 2px 8px; " +
+                        "-fx-background-radius: 4px;"
+                    )
+                );
+                
+                deleteButton.setOnMouseExited(e -> 
+                    deleteButton.setStyle(
+                        "-fx-background-color: transparent; " +
+                        "-fx-text-fill: #ff3b30; " +
+                        "-fx-font-size: 18px; " +
+                        "-fx-font-weight: bold; " +
+                        "-fx-cursor: hand; " +
+                        "-fx-padding: 2px 8px;"
+                    )
+                );
+                
+                deleteButton.setOnAction(event -> {
+                    NodeRow row = getTableRow().getItem();
+                    if (row != null) {
+                        Alert confirm = new Alert(Alert.AlertType.CONFIRMATION);
+                        confirm.setTitle("Remove Node");
+                        confirm.setHeaderText("Remove " + row.getDisplayName() + "?");
+                        confirm.setContentText("This will remove the node from monitoring.");
+                        
+                        Optional<ButtonType> result = confirm.showAndWait();
+                        if (result.isPresent() && result.get() == ButtonType.OK) {
+                            rows.remove(row);
+                            log("Removed node: " + row.getDisplayName());
+                        }
+                    }
+                });
+            }
+            
+            @Override
+            protected void updateItem(Void item, boolean empty) {
+                super.updateItem(item, empty);
+                if (empty) {
+                    setGraphic(null);
+                } else {
+                    setGraphic(deleteButton);
+                }
+            }
+        });
+        
+        return deleteCol;
+    }
+    
+    // ------------------------------------------------------------
+    // EDITABLE VALUE COLUMN
+    // ------------------------------------------------------------
+    
+    private void handleValueEdit(TableColumn.CellEditEvent<NodeRow, String> event) {
+        NodeRow row = event.getRowValue();
+        String newValue = event.getNewValue();
+        String oldValue = event.getOldValue();
+        
+        if (newValue == null || newValue.equals(oldValue)) {
+            return;
+        }
+        
+        if (!opc.isConnected()) {
+            alert("Write Error", "Not connected to OPC UA server");
+            row.setValue(oldValue);
+            return;
+        }
+        
+        if (!row.isReadable()) {
+            alert("Write Error", "Node is not writable");
+            row.setValue(oldValue);
+            return;
+        }
+        
+        log("Writing " + newValue + " to " + row.getNodeId());
+        
+        opc.writeValue(row.getNodeId(), newValue)
+            .thenAccept(success -> Platform.runLater(() -> {
+                if (success) {
+                    row.setValue(newValue);
+                    log("✅ Write successful: " + row.getNodeId() + " = " + newValue);
+                } else {
+                    alert("Write Failed", "Failed to write value to " + row.getNodeId());
+                    row.setValue(oldValue);
+                }
+            }))
+            .exceptionally(ex -> {
+                Platform.runLater(() -> {
+                    alert("Write Error", "Error: " + ex.getMessage());
+                    row.setValue(oldValue);
+                });
+                return null;
+            });
+    }
+    
+    private class EditableValueCell extends TableCell<NodeRow, String> {
+        private TextField textField;
+        
+        @Override
+        public void startEdit() {
+            NodeRow row = getTableRow().getItem();
+            if (row == null || !row.isReadable()) {
+                return;
+            }
+            
+            if (!opc.isConnected()) {
+                return;
+            }
+            
+            super.startEdit();
+            
+            if (textField == null) {
+                createTextField();
+            }
+            
+            textField.setText(getItem());
+            setText(null);
+            setGraphic(textField);
+            textField.selectAll();
+            textField.requestFocus();
+        }
+        
+        @Override
+        public void cancelEdit() {
+            super.cancelEdit();
+            setText(getItem());
+            setGraphic(null);
+        }
+        
+        @Override
+        protected void updateItem(String item, boolean empty) {
+            super.updateItem(item, empty);
+            
+            if (empty) {
+                setText(null);
+                setGraphic(null);
+                setStyle("");
+            } else {
+                if (isEditing()) {
+                    if (textField != null) {
+                        textField.setText(getItem());
+                    }
+                    setText(null);
+                    setGraphic(textField);
+                } else {
+                    setText(item);
+                    setGraphic(null);
+                    
+                    NodeRow row = getTableRow().getItem();
+                    if (row != null && row.isReadable() && opc.isConnected()) {
+                        setStyle("-fx-background-color: #e8f5e9;");
+                        setTooltip(new Tooltip("Double-click to edit"));
+                    } else {
+                        setStyle("");
+                    }
+                }
+            }
+        }
+        
+        private void createTextField() {
+            textField = new TextField(getItem());
+            textField.setMinWidth(getWidth() - getGraphicTextGap() * 2);
+            
+            textField.setOnAction(evt -> commitEdit(textField.getText()));
+            
+            textField.focusedProperty().addListener((obs, was, is) -> {
+                if (!is) {
+                    commitEdit(textField.getText());
+                }
+            });
+        }
+    }
+
+    public static final class JsOpcBridge {
+        private final OpcUaService opc;
+        public JsOpcBridge(OpcUaService opc) { this.opc = opc; }
+        public boolean isConnected() { return opc.isConnected(); }
+    }
+
+
+  }
+
diff --git a/src/main/resources/styles/application.css b/src/main/resources/styles/application.css
new file mode 100644
index 0000000..c4c70ec
--- /dev/null
+++ b/src/main/resources/styles/application.css
@@ -0,0 +1,454 @@
+/* OPCUA GUI Stylesheet */
+/* Place this in src/main/resources/styles/application.css */
+
+/* ============================================================================
+   ROOT & GENERAL
+   ============================================================================ */
+.root {
+    -fx-font-family: "Segoe UI", Arial, sans-serif;
+    -fx-font-size: 13px;
+    -fx-base: #f4f4f4;
+    -fx-background: #ffffff;
+}
+
+/* ============================================================================
+   ACTION BUTTONS
+   ============================================================================ */
+.action-button {
+    -fx-background-color: linear-gradient(to bottom, #4CAF50, #45a049);
+    -fx-text-fill: white;
+    -fx-font-weight: bold;
+    -fx-padding: 5 15 5 15;
+    -fx-border-radius: 4;
+    -fx-background-radius: 4;
+    -fx-cursor: hand;
+}
+
+.action-button:hover {
+    -fx-background-color: linear-gradient(to bottom, #45a049, #3d8b40);
+    -fx-effect: dropshadow(gaussian, rgba(0,0,0,0.3), 4, 0, 0, 1);
+}
+
+.action-button:pressed {
+    -fx-background-color: #3d8b40;
+    -fx-effect: innershadow(gaussian, rgba(0,0,0,0.3), 4, 0, 0, 1);
+}
+
+.action-button:disabled {
+    -fx-opacity: 0.5;
+    -fx-cursor: default;
+}
+
+/* ============================================================================
+   TABLE VIEW
+   ============================================================================ */
+.table-view {
+    -fx-background-color: transparent;
+    -fx-table-cell-border-color: transparent;
+}
+
+.table-view .column-header {
+    -fx-background-color: linear-gradient(to bottom, #e0e0e0, #d0d0d0);
+    -fx-font-weight: bold;
+    -fx-padding: 5;
+}
+
+.table-view .column-header-background {
+    -fx-background-color: #e0e0e0;
+}
+
+.table-row-cell {
+    -fx-border-color: transparent;
+    -fx-border-width: 0;
+}
+
+.table-row-cell:selected {
+    -fx-background-color: #e3f2fd;
+    -fx-table-cell-border-color: #2196F3;
+}
+
+.table-row-cell:hover {
+    -fx-background-color: #f5f5f5;
+}
+
+.table-row-cell:selected:hover {
+    -fx-background-color: #bbdefb;
+}
+
+/* Checkbox column styling */
+.check-box-table-cell .check-box {
+    -fx-cursor: hand;
+}
+
+/* ============================================================================
+   TREE VIEW
+   ============================================================================ */
+.tree-view {
+    -fx-background-color: white;
+    -fx-border-color: #d0d0d0;
+    -fx-border-width: 1;
+}
+
+.tree-cell {
+    -fx-padding: 2 5 2 5;
+}
+
+.tree-cell:selected {
+    -fx-background-color: #2196F3;
+    -fx-text-fill: white;
+}
+
+.tree-cell:hover {
+    -fx-background-color: #e3f2fd;
+}
+
+/* ============================================================================
+   BUTTONS
+   ============================================================================ */
+.button {
+    -fx-background-color: linear-gradient(to bottom, #f0f0f0, #d0d0d0);
+    -fx-border-color: #a0a0a0;
+    -fx-border-width: 1;
+    -fx-border-radius: 3;
+    -fx-background-radius: 3;
+    -fx-padding: 5 15 5 15;
+    -fx-cursor: hand;
+}
+
+.button:hover {
+    -fx-background-color: linear-gradient(to bottom, #e0e0e0, #c0c0c0);
+    -fx-border-color: #808080;
+}
+
+.button:pressed {
+    -fx-background-color: #c0c0c0;
+}
+
+.button:disabled {
+    -fx-opacity: 0.6;
+    -fx-cursor: default;
+}
+
+/* Primary button style */
+.button-primary {
+    -fx-background-color: linear-gradient(to bottom, #2196F3, #1976D2);
+    -fx-text-fill: white;
+    -fx-font-weight: bold;
+}
+
+.button-primary:hover {
+    -fx-background-color: linear-gradient(to bottom, #1976D2, #1565C0);
+}
+
+/* Danger button style */
+.button-danger {
+    -fx-background-color: linear-gradient(to bottom, #f44336, #d32f2f);
+    -fx-text-fill: white;
+}
+
+.button-danger:hover {
+    -fx-background-color: linear-gradient(to bottom, #d32f2f, #c62828);
+}
+
+/* Success button style */
+.button-success {
+    -fx-background-color: linear-gradient(to bottom, #4CAF50, #388E3C);
+    -fx-text-fill: white;
+}
+
+.button-success:hover {
+    -fx-background-color: linear-gradient(to bottom, #388E3C, #2E7D32);
+}
+
+/* ============================================================================
+   TEXT FIELDS & AREAS
+   ============================================================================ */
+.text-field, .text-area {
+    -fx-background-color: white;
+    -fx-border-color: #c0c0c0;
+    -fx-border-width: 1;
+    -fx-border-radius: 3;
+    -fx-background-radius: 3;
+    -fx-padding: 5;
+}
+
+.text-field:focused, .text-area:focused {
+    -fx-border-color: #2196F3;
+    -fx-border-width: 2;
+}
+
+.text-area {
+    -fx-font-family: "Consolas", "Monaco", "Courier New", monospace;
+    -fx-font-size: 12px;
+}
+
+/* ============================================================================
+   DIALOGS
+   ============================================================================ */
+.dialog-pane {
+    -fx-background-color: white;
+    -fx-padding: 10;
+}
+
+.dialog-pane .header-panel {
+    -fx-background-color: linear-gradient(to bottom, #e0e0e0, #d0d0d0);
+    -fx-padding: 10;
+}
+
+.dialog-pane .content {
+    -fx-padding: 20;
+}
+
+.dialog-pane .button-bar .button {
+    -fx-min-width: 80;
+}
+
+/* ============================================================================
+   COMBO BOX
+   ============================================================================ */
+.combo-box {
+    -fx-background-color: white;
+    -fx-border-color: #c0c0c0;
+    -fx-border-width: 1;
+    -fx-border-radius: 3;
+    -fx-background-radius: 3;
+}
+
+.combo-box:focused {
+    -fx-border-color: #2196F3;
+    -fx-border-width: 2;
+}
+
+.combo-box-popup .list-view {
+    -fx-background-color: white;
+    -fx-border-color: #2196F3;
+    -fx-border-width: 1;
+}
+
+.combo-box-popup .list-cell {
+    -fx-padding: 5;
+}
+
+.combo-box-popup .list-cell:hover {
+    -fx-background-color: #e3f2fd;
+}
+
+/* ============================================================================
+   LIST VIEW
+   ============================================================================ */
+.list-view {
+    -fx-background-color: white;
+    -fx-border-color: #d0d0d0;
+    -fx-border-width: 1;
+}
+
+.list-cell {
+    -fx-padding: 5;
+}
+
+.list-cell:selected {
+    -fx-background-color: #2196F3;
+    -fx-text-fill: white;
+}
+
+.list-cell:hover {
+    -fx-background-color: #e3f2fd;
+}
+
+/* ============================================================================
+   CHECK BOX
+   ============================================================================ */
+.check-box {
+    -fx-cursor: hand;
+}
+
+.check-box:selected .box {
+    -fx-background-color: #2196F3;
+    -fx-border-color: #1976D2;
+}
+
+/* ============================================================================
+   LABELS
+   ============================================================================ */
+.label {
+    -fx-text-fill: #333333;
+}
+
+.label-header {
+    -fx-font-size: 16px;
+    -fx-font-weight: bold;
+    -fx-text-fill: #1976D2;
+}
+
+.label-error {
+    -fx-text-fill: #d32f2f;
+    -fx-font-weight: bold;
+}
+
+.label-success {
+    -fx-text-fill: #388E3C;
+    -fx-font-weight: bold;
+}
+
+.label-warning {
+    -fx-text-fill: #F57C00;
+    -fx-font-weight: bold;
+}
+
+/* ============================================================================
+   PROGRESS INDICATOR
+   ============================================================================ */
+.progress-indicator {
+    -fx-progress-color: #2196F3;
+}
+
+/* ============================================================================
+   SEPARATOR
+   ============================================================================ */
+.separator {
+    -fx-background-color: #d0d0d0;
+}
+
+/* ============================================================================
+   SCROLL BAR
+   ============================================================================ */
+.scroll-bar {
+    -fx-background-color: transparent;
+}
+
+.scroll-bar .thumb {
+    -fx-background-color: #c0c0c0;
+    -fx-background-radius: 5;
+}
+
+.scroll-bar .thumb:hover {
+    -fx-background-color: #a0a0a0;
+}
+
+.scroll-bar .increment-button,
+.scroll-bar .decrement-button {
+    -fx-background-color: transparent;
+}
+
+/* ============================================================================
+   CUSTOM CLASSES
+   ============================================================================ */
+
+/* Action list item in dialog */
+.action-list-item {
+    -fx-padding: 5;
+    -fx-border-color: #e0e0e0;
+    -fx-border-width: 0 0 1 0;
+}
+
+.action-list-item:hover {
+    -fx-background-color: #f5f5f5;
+}
+
+/* Script editor */
+.script-editor {
+    -fx-font-family: "Consolas", "Monaco", "Courier New", monospace;
+    -fx-font-size: 12px;
+    -fx-background-color: #f8f8f8;
+    -fx-border-color: #2196F3;
+    -fx-border-width: 2;
+    -fx-padding: 10;
+}
+
+/* Status indicator */
+.status-connected {
+    -fx-background-color: #4CAF50;
+    -fx-background-radius: 50%;
+    -fx-min-width: 12;
+    -fx-min-height: 12;
+    -fx-max-width: 12;
+    -fx-max-height: 12;
+}
+
+.status-disconnected {
+    -fx-background-color: #f44336;
+    -fx-background-radius: 50%;
+    -fx-min-width: 12;
+    -fx-min-height: 12;
+    -fx-max-width: 12;
+    -fx-max-height: 12;
+}
+
+/* Tooltip */
+.tooltip {
+    -fx-background-color: #333333;
+    -fx-text-fill: white;
+    -fx-padding: 5 10 5 10;
+    -fx-background-radius: 4;
+    -fx-font-size: 12px;
+}
+
+/* Badge for action count */
+.badge {
+    -fx-background-color: #2196F3;
+    -fx-text-fill: white;
+    -fx-background-radius: 10;
+    -fx-padding: 2 6 2 6;
+    -fx-font-size: 10px;
+    -fx-font-weight: bold;
+}
+
+/* Grid pane for forms */
+.form-grid {
+    -fx-hgap: 10;
+    -fx-vgap: 10;
+    -fx-padding: 10;
+}
+
+/* ============================================================================
+   RESPONSIVE MAIN WINDOW
+   ============================================================================ */
+.top-bar {
+    -fx-background-color: linear-gradient(to bottom, #ffffff, #eef3f9);
+    -fx-border-color: #d0d7de;
+    -fx-border-width: 0 0 1 0;
+}
+
+.app-title {
+    -fx-font-size: 18px;
+    -fx-font-weight: bold;
+    -fx-text-fill: #17456b;
+}
+
+.script-bar {
+    -fx-padding: 4 0 0 0;
+}
+
+.split-pane {
+    -fx-background-color: #f7f9fb;
+}
+
+.split-pane-divider {
+    -fx-background-color: #d0d7de;
+    -fx-padding: 0 1 0 1;
+}
+
+.table-view {
+    -fx-column-resize-policy: constrained-resize;
+}
+
+/* JavaScript editor (RichTextFX) */
+.js-editor-pane {
+    -fx-border-color: #d0d7de;
+    -fx-border-radius: 8;
+    -fx-background-radius: 8;
+    -fx-background-color: #ffffff;
+}
+.js-editor-header {
+    -fx-padding: 6 8 6 8;
+    -fx-background-color: #f6f8fa;
+    -fx-border-color: transparent transparent #d0d7de transparent;
+}
+.js-code-area {
+    -fx-font-family: "Cascadia Code", "JetBrains Mono", "Consolas", monospace;
+    -fx-font-size: 13px;
+    -fx-background-color: #ffffff;
+}
+.js-code-area .keyword { -fx-fill: #cf222e; -fx-font-weight: bold; }
+.js-code-area .string  { -fx-fill: #0a3069; }
+.js-code-area .comment { -fx-fill: #6e7781; -fx-font-style: italic; }
diff --git a/src/main/resources/styles/opcua-client-logo.png b/src/main/resources/styles/opcua-client-logo.png
new file mode 100644
index 0000000..3da1fd6
Binary files /dev/null and b/src/main/resources/styles/opcua-client-logo.png differ
diff --git a/src/main/resources/styles/opcua-client-logo.svg b/src/main/resources/styles/opcua-client-logo.svg
new file mode 100644
index 0000000..999be1a
--- /dev/null
+++ b/src/main/resources/styles/opcua-client-logo.svg
@@ -0,0 +1,27 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256">
+  <defs>
+    <linearGradient id="g" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0" stop-color="#007aff"/>
+      <stop offset="1" stop-color="#34c759"/>
+    </linearGradient>
+    <filter id="s" x="-20%" y="-20%" width="140%" height="140%">
+      <feDropShadow dx="0" dy="8" stdDeviation="10" flood-color="#0b2a42" flood-opacity="0.25"/>
+    </filter>
+  </defs>
+  <rect x="20" y="20" width="216" height="216" rx="50" fill="url(#g)" filter="url(#s)"/>
+  <circle cx="128" cy="128" r="72" fill="none" stroke="white" stroke-width="14" opacity="0.95"/>
+  <circle cx="128" cy="128" r="22" fill="white"/>
+  <g fill="white" opacity="0.95">
+    <circle cx="128" cy="45" r="12"/>
+    <circle cx="128" cy="211" r="12"/>
+    <circle cx="45" cy="128" r="12"/>
+    <circle cx="211" cy="128" r="12"/>
+  </g>
+  <g stroke="white" stroke-width="10" stroke-linecap="round" opacity="0.85">
+    <line x1="128" y1="57" x2="128" y2="90"/>
+    <line x1="128" y1="166" x2="128" y2="199"/>
+    <line x1="57" y1="128" x2="90" y2="128"/>
+    <line x1="166" y1="128" x2="199" y2="128"/>
+  </g>
+  <text x="128" y="238" text-anchor="middle" font-family="Segoe UI, Arial, sans-serif" font-size="28" font-weight="700" fill="white" opacity="0.95">OPC</text>
+</svg>
diff --git a/src/main/resources/styles/opcua-client.ico b/src/main/resources/styles/opcua-client.ico
new file mode 100644
index 0000000..a3b18c4
Binary files /dev/null and b/src/main/resources/styles/opcua-client.ico differ
diff --git a/src/main/resources/styles/opcua-simulator-icon.png b/src/main/resources/styles/opcua-simulator-icon.png
new file mode 100644
index 0000000..2a339b7
Binary files /dev/null and b/src/main/resources/styles/opcua-simulator-icon.png differ
diff --git a/src/main/resources/ui/config.fxml b/src/main/resources/ui/config.fxml
new file mode 100644
index 0000000..9359124
--- /dev/null
+++ b/src/main/resources/ui/config.fxml
@@ -0,0 +1,159 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.control.*?>
+<?import javafx.scene.layout.*?>
+
+<BorderPane xmlns="http://javafx.com/javafx/21" xmlns:fx="http://javafx.com/fxml/1"
+            fx:controller="de.opcua.app.ui.ConfigController"
+            prefWidth="980" prefHeight="760">
+  <top>
+    <Label text="Configuration" style="-fx-font-size:22px;-fx-font-weight:bold;" BorderPane.alignment="CENTER_LEFT">
+      <padding><Insets top="14" right="18" bottom="8" left="18"/></padding>
+    </Label>
+  </top>
+  <center>
+    <ScrollPane fitToWidth="true">
+      <VBox spacing="16">
+        <padding><Insets top="18" right="18" bottom="18" left="18"/></padding>
+        <TitledPane text="OPC UA Server" expanded="true">
+          <GridPane hgap="12" vgap="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <columnConstraints>
+              <ColumnConstraints minWidth="170" halignment="RIGHT"/>
+              <ColumnConstraints hgrow="ALWAYS"/>
+            </columnConstraints>
+            <Label text="Endpoint" GridPane.rowIndex="0" GridPane.columnIndex="0"/>
+            <TextField fx:id="endpointTextBox" GridPane.rowIndex="0" GridPane.columnIndex="1"/>
+            <Label text="Host" GridPane.rowIndex="1" GridPane.columnIndex="0"/>
+            <TextField fx:id="hostTextBox" GridPane.rowIndex="1" GridPane.columnIndex="1"/>
+          </GridPane>
+        </TitledPane>
+
+        <TitledPane text="HTTP / HTTPS" expanded="true">
+          <GridPane hgap="12" vgap="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <columnConstraints>
+              <ColumnConstraints minWidth="170" halignment="RIGHT"/>
+              <ColumnConstraints hgrow="ALWAYS"/>
+              <ColumnConstraints minWidth="110"/>
+            </columnConstraints>
+            <CheckBox fx:id="httpEnabledCheckBox" text="Enable HTTP" GridPane.rowIndex="0" GridPane.columnIndex="1"/>
+            <Label text="HTTP Port" GridPane.rowIndex="1" GridPane.columnIndex="0"/>
+            <TextField fx:id="httpPortTextBox" GridPane.rowIndex="1" GridPane.columnIndex="1" maxWidth="140"/>
+            <Label text="z. B. 8081" GridPane.rowIndex="1" GridPane.columnIndex="2" style="-fx-text-fill:#888;"/>
+
+            <CheckBox fx:id="httpsEnabledCheckBox" text="Enable HTTPS" GridPane.rowIndex="2" GridPane.columnIndex="1"/>
+            <Label text="HTTPS Port" GridPane.rowIndex="3" GridPane.columnIndex="0"/>
+            <TextField fx:id="httpsPortTextBox" GridPane.rowIndex="3" GridPane.columnIndex="1" maxWidth="140"/>
+            <Label text="z. B. 8443" GridPane.rowIndex="3" GridPane.columnIndex="2" style="-fx-text-fill:#888;"/>
+            <Label text="Keystore" GridPane.rowIndex="4" GridPane.columnIndex="0"/>
+            <HBox spacing="8" GridPane.rowIndex="4" GridPane.columnIndex="1" GridPane.columnSpan="2">
+              <TextField fx:id="keystorePathTextBox" HBox.hgrow="ALWAYS"/>
+              <Button text="Browse..." onAction="#BrowseKeystore_Click"/>
+            </HBox>
+            <Label text="Keystore Password" GridPane.rowIndex="5" GridPane.columnIndex="0"/>
+            <PasswordField fx:id="keystorePasswordTextBox" GridPane.rowIndex="5" GridPane.columnIndex="1"/>
+            <Label text="Keystore Type" GridPane.rowIndex="6" GridPane.columnIndex="0"/>
+            <ComboBox fx:id="keystoreTypeComboBox" GridPane.rowIndex="6" GridPane.columnIndex="1" maxWidth="160"/>
+          </GridPane>
+        </TitledPane>
+
+
+        <TitledPane text="Portable Config / Verschluesselung / REST Auth" expanded="true">
+          <GridPane hgap="12" vgap="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <columnConstraints>
+              <ColumnConstraints minWidth="190" halignment="RIGHT"/>
+              <ColumnConstraints hgrow="ALWAYS"/>
+            </columnConstraints>
+
+            <Label text="Config-Verzeichnis" GridPane.rowIndex="0" GridPane.columnIndex="0"/>
+            <Label fx:id="configDirectoryLabel" GridPane.rowIndex="0" GridPane.columnIndex="1" style="-fx-text-fill:#666;-fx-font-family:monospace;" wrapText="true"/>
+
+            <Label text="Settings-Datei" GridPane.rowIndex="1" GridPane.columnIndex="0"/>
+            <Label fx:id="settingsPathLabel" GridPane.rowIndex="1" GridPane.columnIndex="1" style="-fx-text-fill:#666;-fx-font-family:monospace;" wrapText="true"/>
+
+            <CheckBox fx:id="configEncryptionEnabledCheckBox" text="Config-Dateien verschluesseln (Actions, Templates, System Init)" GridPane.rowIndex="2" GridPane.columnIndex="1"/>
+            <Label text="Config-Passwort" GridPane.rowIndex="3" GridPane.columnIndex="0"/>
+            <PasswordField fx:id="configEncryptionPasswordField" GridPane.rowIndex="3" GridPane.columnIndex="1" promptText="Passwort fuer AES-GCM Verschluesselung"/>
+
+            <CheckBox fx:id="restAuthEnabledCheckBox" text="REST-API Authentifizierung aktivieren" GridPane.rowIndex="4" GridPane.columnIndex="1"/>
+            <Label text="REST Benutzer" GridPane.rowIndex="5" GridPane.columnIndex="0"/>
+            <TextField fx:id="restAuthUserTextBox" GridPane.rowIndex="5" GridPane.columnIndex="1" promptText="admin"/>
+            <Label text="REST Passwort" GridPane.rowIndex="6" GridPane.columnIndex="0"/>
+            <PasswordField fx:id="restAuthPasswordField" GridPane.rowIndex="6" GridPane.columnIndex="1" promptText="Leer lassen = bestehendes Passwort behalten"/>
+
+            <Label text="Hinweis" GridPane.rowIndex="7" GridPane.columnIndex="0"/>
+            <Label text="Nach Aktivierung der REST-Authentifizierung muessen REST-Clients Basic Auth verwenden. Die Web-Oberflaeche fragt das Passwort automatisch ab." GridPane.rowIndex="7" GridPane.columnIndex="1" wrapText="true" style="-fx-text-fill:#666;"/>
+          </GridPane>
+        </TitledPane>
+
+        <TitledPane text="System Init / RegLogin" expanded="true">
+          <VBox spacing="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <Label text="Dieses globale Initial-Script wird dauerhaft gespeichert und beim Start/Connect geladen. Im Service-Modus laeuft es nach erfolgreichem OPC-Connect/Reconnect, wenn 'Nach OPC Connect' aktiv ist." wrapText="true"/>
+            <Label fx:id="systemInitPathLabel" style="-fx-text-fill:#666;-fx-font-family:monospace;"/>
+            <HBox spacing="18">
+              <CheckBox fx:id="systemInitEnabledCheckBox" text="Aktiv"/>
+              <CheckBox fx:id="systemInitRunAtProgramStartCheckBox" text="Bei Programmstart"/>
+              <CheckBox fx:id="systemInitRunAfterConnectCheckBox" text="Nach OPC Connect/Reconnect" selected="true"/>
+            </HBox>
+            <HBox spacing="8">
+              <Button text="RegLogin Template einfuegen" onAction="#InsertRegLoginTemplate_Click"/>
+              <Button text="Speichern &amp; jetzt ausfuehren" onAction="#RunSystemInit_Click"/>
+            </HBox>
+            <StackPane fx:id="systemInitEditorHost" minHeight="280" VBox.vgrow="ALWAYS"/>
+          </VBox>
+        </TitledPane>
+
+        <TitledPane text="Script Templates / Button-Vorlagen" expanded="false">
+          <VBox spacing="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <Label text="Hier werden GET/POST/SET und eigene Templates gepflegt. Fuer jedes aktivierte Template erscheint im Create-New-Action-Dialog automatisch ein Button. Platzhalter werden beim Einfuegen durch feste NodeId-Codezeilen ersetzt." wrapText="true"/>
+            <Label fx:id="templatePathLabel" style="-fx-text-fill:#666;-fx-font-family:monospace;"/>
+            <SplitPane dividerPositions="0.30" minHeight="360" VBox.vgrow="ALWAYS">
+              <items>
+                <VBox spacing="8">
+                  <ListView fx:id="templateListView" minWidth="220" VBox.vgrow="ALWAYS"/>
+                  <HBox spacing="8">
+                    <Button text="Neu" onAction="#NewTemplate_Click"/>
+                    <Button text="Loeschen" onAction="#DeleteTemplate_Click"/>
+                  </HBox>
+                </VBox>
+                <VBox spacing="8">
+                  <GridPane hgap="10" vgap="8">
+                    <columnConstraints>
+                      <ColumnConstraints minWidth="90" halignment="RIGHT"/>
+                      <ColumnConstraints hgrow="ALWAYS"/>
+                    </columnConstraints>
+                    <Label text="Name" GridPane.rowIndex="0" GridPane.columnIndex="0"/>
+                    <TextField fx:id="templateNameField" GridPane.rowIndex="0" GridPane.columnIndex="1" promptText="z. B. POST an MES"/>
+                    <Label text="Status" GridPane.rowIndex="1" GridPane.columnIndex="0"/>
+                    <CheckBox fx:id="templateEnabledCheckBox" text="Aktiv / Button anzeigen" selected="true" GridPane.rowIndex="1" GridPane.columnIndex="1"/>
+                  </GridPane>
+                  <HBox spacing="8">
+                    <Button text="Platzhalter einfuegen" onAction="#InsertTemplatePlaceholders_Click"/>
+                    <Button text="Templates speichern" onAction="#SaveTemplates_Click"/>
+                    <Button text="Standard GET/POST/SET wiederherstellen" onAction="#ResetTemplates_Click"/>
+                  </HBox>
+                  <Label text="JavaScript Template" style="-fx-font-weight:bold;"/>
+                  <StackPane fx:id="templateEditorHost" minHeight="260" VBox.vgrow="ALWAYS"/>
+                  <Label text="Platzhalter: {{readNumberVars}}, {{readTextVars}}, {{payloadFields}}, {{opcWritesFromResult}}, {{selectedNodesComment}}, {{firstNodeIdJs}}, {{firstAlias}}" wrapText="true" style="-fx-text-fill:#666;"/>
+                </VBox>
+              </items>
+            </SplitPane>
+          </VBox>
+        </TitledPane>
+
+      </VBox>
+    </ScrollPane>
+  </center>
+  <bottom>
+    <HBox spacing="10" alignment="CENTER_RIGHT">
+      <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+      <Button text="Save" prefWidth="110" onAction="#SaveButton_Click" style="-fx-background-color:#007aff;-fx-text-fill:white;-fx-font-weight:bold;"/>
+      <Button text="Cancel" prefWidth="110" onAction="#CancelButton_Click" style="-fx-background-color:#8e8e93;-fx-text-fill:white;"/>
+    </HBox>
+  </bottom>
+</BorderPane>
diff --git a/src/main/resources/ui/main.fxml b/src/main/resources/ui/main.fxml
new file mode 100644
index 0000000..a04a82a
--- /dev/null
+++ b/src/main/resources/ui/main.fxml
@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.control.*?>
+<?import javafx.scene.image.Image?>
+<?import javafx.scene.image.ImageView?>
+<?import javafx.scene.layout.*?>
+
+<BorderPane xmlns:fx="http://javafx.com/fxml"
+            fx:controller="de.opcua.app.ui.MainController"
+            prefWidth="1262" prefHeight="619"
+            minWidth="900" minHeight="520"
+            stylesheets="@../styles/application.css">
+
+  <top>
+    <HBox spacing="8" alignment="CENTER_LEFT" styleClass="top-bar">
+      <padding>
+        <Insets top="10" right="12" bottom="10" left="12"/>
+      </padding>
+      <ImageView fitWidth="28" fitHeight="28" preserveRatio="true" smooth="true">
+        <image>
+          <Image url="@../styles/opcua-client-logo.png"/>
+        </image>
+      </ImageView>
+      <Label text="OPC UA Client" styleClass="app-title"/>
+      <Region HBox.hgrow="ALWAYS"/>
+      <Button fx:id="connectButton" text="Connect" minWidth="92" onAction="#connectButton_Click" styleClass="button-primary"/>
+      <Button fx:id="saveButton" text="Save" minWidth="80" onAction="#onSave"/>
+      <Button fx:id="settingsButton" text="Settings" minWidth="92" onAction="#onSettings"/>
+    </HBox>
+  </top>
+
+  <center>
+    <SplitPane dividerPositions="0.25" BorderPane.alignment="CENTER">
+      <items>
+        <VBox spacing="8" minWidth="240">
+          <padding>
+            <Insets top="10" right="6" bottom="10" left="10"/>
+          </padding>
+          <Label text="OPC UA Tree" styleClass="label-header"/>
+          <TreeView fx:id="myTreeView" VBox.vgrow="ALWAYS" minWidth="220"
+                    onMouseClicked="#myTreeView_AfterSelect"/>
+        </VBox>
+
+        <VBox spacing="8" minWidth="520">
+          <padding>
+            <Insets top="10" right="10" bottom="10" left="6"/>
+          </padding>
+          <TableView fx:id="nodeListview" VBox.vgrow="ALWAYS" minHeight="260">
+            <columns>
+              <TableColumn fx:id="checkBoxColumn" text="Select" prefWidth="70"/>
+              <TableColumn fx:id="colDisplayName" text="DisplayName" prefWidth="160"/>
+              <TableColumn fx:id="colNodeType" text="NodeType" prefWidth="110"/>
+              <TableColumn fx:id="colNodeId" text="NodeId" prefWidth="280"/>
+              <TableColumn fx:id="colNamespaceIndex" text="NamespaceIndex" prefWidth="120"/>
+              <TableColumn fx:id="colIdentifierType" text="IdentifierType" prefWidth="120"/>
+              <TableColumn fx:id="colValue" text="Value" prefWidth="150"/>
+            </columns>
+            <columnResizePolicy>
+              <TableView fx:constant="CONSTRAINED_RESIZE_POLICY"/>
+            </columnResizePolicy>
+          </TableView>
+
+          <HBox spacing="8" alignment="CENTER_LEFT" styleClass="script-bar">
+            <Label text="JS:"/>
+            <TextField fx:id="scriptField" HBox.hgrow="ALWAYS" promptText="opc.read(&quot;ns=...&quot;)"/>
+            <Button fx:id="runScriptButton" text="Run" minWidth="70" onAction="#runScript"/>
+          </HBox>
+
+          <TextArea fx:id="logArea" visible="false" managed="false" prefRowCount="0"/>
+        </VBox>
+      </items>
+    </SplitPane>
+  </center>
+</BorderPane>
diff --git a/src/main/resources/web/web-interface.html b/src/main/resources/web/web-interface.html
new file mode 100644
index 0000000..54ceed0
--- /dev/null
+++ b/src/main/resources/web/web-interface.html
@@ -0,0 +1,1217 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
+    <meta name="mobile-web-app-capable" content="yes">
+    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
+    <meta name="theme-color" content="#007aff" media="(prefers-color-scheme: light)">
+    <meta name="theme-color" content="#0a0a0a" media="(prefers-color-scheme: dark)">
+    <title>OPC UA Control</title>
+    <link rel="icon" href="/favicon.ico">
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.16/codemirror.min.css">
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.16/theme/material-darker.min.css">
+    <style>
+        :root {
+            --bg-primary: #f2f2f7;
+            --bg-secondary: #ffffff;
+            --bg-tertiary: #f2f2f7;
+            --text-primary: #1c1c1e;
+            --text-secondary: #8e8e93;
+            --border-color: rgba(60,60,67,0.18);
+            --blue: #007aff;
+            --green: #34c759;
+            --red: #ff3b30;
+            --orange: #ff9500;
+            --shadow: 0 1px 3px rgba(0,0,0,0.08);
+        }
+        @media (prefers-color-scheme: dark) {
+            :root {
+                --bg-primary: #000000;
+                --bg-secondary: #1c1c1e;
+                --bg-tertiary: #2c2c2e;
+                --text-primary: #ffffff;
+                --text-secondary: #98989d;
+                --border-color: rgba(84,84,88,0.48);
+                --shadow: 0 1px 3px rgba(0,0,0,0.3);
+            }
+        }
+        * { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
+        body { font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', Arial, sans-serif; background: var(--bg-primary); color: var(--text-primary); }
+        .header { background: var(--blue); color: white; padding: max(env(safe-area-inset-top), 20px) 20px 20px 20px; box-shadow: 0 2px 10px rgba(0,0,0,0.2); position: sticky; top: 0; z-index: 100; }
+        .header h1 { font-size: clamp(20px, 5vw, 28px); font-weight: 700; margin-bottom: 8px; display:flex; align-items:center; gap:10px; }
+        .app-logo { width: 36px; height: 36px; border-radius: 10px; box-shadow: 0 2px 8px rgba(0,0,0,0.20); flex-shrink: 0; }
+        .status-badge { display: inline-flex; align-items: center; gap: 6px; background: rgba(255,255,255,0.2); padding: 6px 12px; border-radius: 20px; font-size: 13px; font-weight: 600; }
+        .status-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--red); }
+        .status-dot.connected { background: var(--green); animation: pulse 2s infinite; }
+        @keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.6; } }
+        .toolbar { background: var(--bg-secondary); padding: 12px 20px; border-bottom: 0.5px solid var(--border-color); display: flex; gap: 8px; overflow-x: auto; -webkit-overflow-scrolling: touch; align-items: center; }
+        .toolbar::-webkit-scrollbar { display: none; }
+        .btn { background: var(--blue); color: white; border: none; padding: 10px 16px; border-radius: 10px; font-size: 15px; font-weight: 600; cursor: pointer; transition: all 0.2s; white-space: nowrap; touch-action: manipulation; }
+        .btn:active { transform: scale(0.96); }
+        .btn-success { background: var(--green); }
+        .btn-danger { background: var(--red); }
+        .btn-secondary { background: var(--text-secondary); }
+        .btn-small { padding: 6px 12px; font-size: 13px; border-radius: 8px; }
+        .btn:disabled { opacity: 0.5; cursor: not-allowed; }
+        .twin-status { font-size: 12px; color: var(--text-secondary); white-space: nowrap; }
+        .container { max-width: 1600px; margin: 0 auto; padding: clamp(12px, 2vw, 20px); padding-bottom: max(env(safe-area-inset-bottom), 16px); }
+        .grid { display: grid; grid-template-columns: 1fr; gap: 16px; }
+        @media (min-width: 768px) { .grid { grid-template-columns: 350px 1fr; } }
+        @media (min-width: 1024px) { .grid { grid-template-columns: 400px 1fr; } }
+        .card { background: var(--bg-secondary); border-radius: 12px; margin-bottom: 16px; box-shadow: var(--shadow); overflow: hidden; }
+        .card-header { padding: 16px; border-bottom: 0.5px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
+        .card-title { font-size: 17px; font-weight: 600; }
+        .tree-container { max-height: 70vh; overflow-y: auto; -webkit-overflow-scrolling: touch; }
+        @media (min-width: 768px) { .tree-container { max-height: 600px; } }
+        .tree-node { padding: 10px 16px; border-bottom: 0.5px solid var(--border-color); cursor: pointer; user-select: none; }
+        .tree-node:active { background: var(--bg-tertiary); }
+        .tree-node-content { display: flex; align-items: center; gap: 8px; }
+        .tree-expand { width: 24px; height: 24px; border-radius: 50%; background: var(--bg-tertiary); display: flex; align-items: center; justify-content: center; font-size: 14px; transition: transform 0.2s; flex-shrink: 0; cursor: pointer; }
+        .tree-expand.expanded { transform: rotate(90deg); }
+        .tree-expand.loading-spin { animation: spin 0.7s linear infinite; }
+        .tree-children { padding-left: 28px; display: none; }
+        .tree-children.show { display: block; }
+        .value-badge { margin-left: 8px; padding: 2px 8px; background: var(--blue); color: white; border-radius: 6px; font-size: 11px; font-weight: 600; font-family: 'SF Mono', Monaco, monospace; }
+        .table-container { overflow-x: auto; -webkit-overflow-scrolling: touch; }
+        table { width: 100%; border-collapse: collapse; font-size: clamp(13px, 2vw, 15px); }
+        thead { background: var(--bg-tertiary); position: sticky; top: 0; z-index: 1; }
+        th { padding: 12px 8px; text-align: left; font-weight: 600; font-size: 13px; color: var(--text-secondary); text-transform: uppercase; border-bottom: 0.5px solid var(--border-color); white-space: nowrap; }
+        td { padding: 12px 8px; border-bottom: 0.5px solid var(--border-color); }
+        .value-cell { font-family: 'SF Mono', Monaco, 'Courier New', monospace; font-size: 14px; font-weight: 500; background: var(--bg-tertiary); padding: 6px 10px; border-radius: 6px; display: inline-block; cursor: pointer; transition: background 0.3s; }
+        .value-cell.updating { animation: highlight 0.5s; }
+        @keyframes highlight { 0%, 100% { background: var(--bg-tertiary); } 50% { background: var(--orange); } }
+        .modal { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.5); z-index: 1000; }
+        .modal.active { display: flex; align-items: flex-end; justify-content: center; }
+        @media (min-width: 768px) { .modal.active { align-items: center; } }
+        .modal-content { background: var(--bg-secondary); border-radius: 12px 12px 0 0; padding: 24px; max-width: 600px; width: 100%; max-height: 85vh; overflow-y: auto; }
+        .modal-content.configuration-content { max-width: 980px; }
+        @media (min-width: 768px) { .modal-content { border-radius: 12px; } }
+        .modal-header { font-size: 20px; font-weight: 700; margin-bottom: 20px; }
+        .configuration-content .modal-header { font-size: 22px; margin-bottom: 14px; }
+        .config-pane { border: 1px solid var(--border-color); border-radius: 12px; margin-bottom: 16px; background: var(--bg-secondary); overflow: hidden; }
+        .config-pane-title { padding: 12px 14px; font-weight: 700; border-bottom: 1px solid var(--border-color); background: var(--bg-tertiary); }
+        .config-pane-body { padding: 14px; }
+        .config-checkbox-row { display:flex; gap:18px; flex-wrap:wrap; align-items:center; margin: 10px 0 12px 0; }
+        .config-path { font-size:12px; color:var(--text-secondary); font-family:'SF Mono', Monaco, monospace; margin: 8px 0 10px 0; word-break: break-all; }
+        .config-actions { display:flex; gap:8px; flex-wrap:wrap; margin-bottom:10px; }
+        .configuration-content .CodeMirror { min-height: 280px; }
+        .form-group { margin-bottom: 16px; }
+        .form-label { display: block; margin-bottom: 8px; font-size: 13px; font-weight: 600; color: var(--text-secondary); text-transform: uppercase; }
+        .form-input, .form-select, .form-textarea { width: 100%; padding: 12px; border: 0.5px solid var(--border-color); border-radius: 10px; font-size: 16px; background: var(--bg-tertiary); color: var(--text-primary); transition: all 0.2s; }
+        .form-input:focus, .form-select:focus, .form-textarea:focus { outline: none; border-color: var(--blue); box-shadow: 0 0 0 4px rgba(0,122,255,0.1); }
+        .form-textarea { min-height: 120px; font-family: 'SF Mono', Monaco, monospace; resize: vertical; }
+        .badge { display: inline-block; padding: 4px 8px; background: var(--blue); color: white; border-radius: 6px; font-size: 12px; font-weight: 600; }
+        .badge-success { background: var(--green); }
+        .badge-warning { background: var(--orange); }
+        .btn-delete { background: none; border: none; color: var(--red); font-size: 20px; cursor: pointer; padding: 4px 8px; border-radius: 6px; }
+        .empty-state { text-align: center; padding: 40px 20px; color: var(--text-secondary); }
+        .empty-icon { font-size: 48px; margin-bottom: 12px; }
+        .spinner { width: 16px; height: 16px; border: 2px solid var(--bg-tertiary); border-top: 2px solid var(--blue); border-radius: 50%; animation: spin 0.8s linear infinite; display: inline-block; vertical-align: middle; }
+        @keyframes spin { to { transform: rotate(360deg); } }
+        .list-item { padding: 12px 16px; border-bottom: 0.5px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
+        .list-item:last-child { border-bottom: none; }
+        .code-helper { border: 1px solid var(--border-color); background: var(--bg-tertiary); border-radius: 10px; padding: 10px; margin-bottom: 12px; }
+        .code-helper-list { max-height: 180px; overflow: auto; border: 1px solid var(--border-color); border-radius: 8px; padding: 8px; background: var(--bg-secondary); margin: 8px 0; }
+        .code-helper-row { display: grid; grid-template-columns: 24px minmax(120px, 1fr) minmax(140px, 1.3fr); gap: 8px; align-items: center; padding: 6px 0; border-bottom: 1px solid var(--border-color); }
+        .code-helper-row:last-child { border-bottom: none; }
+        .code-helper-alias { width: 100%; padding: 6px 8px; border: 1px solid var(--border-color); border-radius: 8px; background: var(--bg-tertiary); color: var(--text-primary); }
+        .CodeMirror { min-height: 220px; border-radius: 10px; font-size: 14px; font-family: 'SF Mono', Monaco, monospace; }
+        .template-manager-grid { display:grid; grid-template-columns:minmax(180px,0.8fr) minmax(260px,1.6fr); gap:12px; }
+        .template-list { min-height:220px; border:1px solid var(--border-color); border-radius:10px; background:var(--bg-secondary); overflow:auto; }
+        .template-list-item { padding:10px 12px; border-bottom:1px solid var(--border-color); cursor:pointer; display:flex; justify-content:space-between; gap:8px; }
+        .template-list-item.active { background:rgba(0,122,255,0.16); }
+        @media(max-width:800px){ .template-manager-grid { grid-template-columns:1fr; } }
+    </style>
+</head>
+<body>
+    <div class="header">
+        <h1><img src="/assets/opcua-client-logo.svg" class="app-logo" alt=""> OPC UA Control</h1>
+        <div class="status-badge">
+            <div class="status-dot" id="statusDot"></div>
+            <span id="statusText">Disconnected</span>
+        </div>
+    </div>
+
+    <div class="toolbar">
+        <button class="btn btn-success" onclick="loadRoot()" id="loadTreeBtn">🌳 Load Tree</button>
+        <button class="btn" onclick="exportTwin()">⬇ Export JSON</button>
+        <button class="btn" onclick="openConfigurationModal()">⚙ Configuration</button>
+        <button class="btn btn-secondary" onclick="window.location.href='/help'">📘 Hilfe / REST API</button>
+        <button class="btn btn-secondary" onclick="window.location.href='/api/openapi.json'">🧭 OpenAPI</button>
+        <button class="btn" onclick="toggleAutoRefresh()"><span id="refreshLabel">▶ Live</span></button>
+        <span class="twin-status" id="twinStatus"></span>
+    </div>
+
+    <div class="container">
+        <div class="grid">
+            <!-- Tree -->
+            <div class="card">
+                <div class="card-header">
+                    <div class="card-title">OPC UA Tree</div>
+                    <div id="treeInfo" style="font-size:12px;color:var(--text-secondary)"></div>
+                </div>
+                <div class="tree-container">
+                    <div id="treeView">
+                        <div class="empty-state">
+                            <div class="empty-icon">🌳</div>
+                            <div>Click "Load Tree"</div>
+                        </div>
+                    </div>
+                </div>
+            </div>
+
+            <!-- Right column -->
+            <div>
+                <div class="card">
+                    <div class="card-header">
+                        <div class="card-title">Monitored Nodes</div>
+                        <span class="badge" id="nodeCount">0</span>
+                    </div>
+                    <div class="table-container">
+                        <table>
+                            <thead>
+                                <tr>
+                                    <th>Name</th>
+                                    <th>NodeID</th>
+                                    <th>NS</th>
+                                    <th>Type</th>
+                                    <th>Value</th>
+                                    <th>Actions</th>
+                                    <th></th>
+                                </tr>
+                            </thead>
+                            <tbody id="nodesTableBody">
+                                <tr><td colspan="7"><div class="empty-state"><div class="empty-icon">📊</div><div>No nodes</div></div></td></tr>
+                            </tbody>
+                        </table>
+                    </div>
+                </div>
+
+                <div class="card">
+                    <div class="card-header">
+                        <div class="card-title">Actions</div>
+                        <span class="badge badge-success" id="actionCount">0</span>
+                    </div>
+                    <div id="actionsList">
+                        <div class="empty-state"><div class="empty-icon">⚡</div><div>No actions</div></div>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+
+
+    <!-- Configuration Modal -->
+    <div class="modal" id="systemInitModal">
+        <div class="modal-content configuration-content">
+            <div class="modal-header">Configuration</div>
+
+            <div class="config-pane">
+                <div class="config-pane-title">Portable Config / Verschlüsselung / REST Auth</div>
+                <div class="config-pane-body">
+                    <div style="font-size:13px;color:var(--text-secondary);line-height:1.45;margin-bottom:8px">
+                        Alle Definitionen werden im Unterordner <b>config</b> neben der Anwendung gespeichert. Optional können Actions, Templates und System Init verschlüsselt werden.
+                    </div>
+                    <div class="config-path" id="configDirectoryLabel">config</div>
+                    <div class="config-path" id="settingsFileLabel">config/settings.json</div>
+
+                    <div class="config-checkbox-row">
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="configEncryptionEnabled"> Config-Dateien verschlüsseln
+                        </label>
+                    </div>
+                    <div class="form-group">
+                        <label class="form-label">Config-Passwort</label>
+                        <input type="password" class="form-input" id="configEncryptionPassword" placeholder="Passwort für AES-GCM Verschlüsselung">
+                    </div>
+
+                    <div class="config-checkbox-row">
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="restAuthEnabled"> REST-API Authentifizierung aktivieren
+                        </label>
+                    </div>
+                    <div class="form-group">
+                        <label class="form-label">REST Benutzer</label>
+                        <input type="text" class="form-input" id="restAuthUser" placeholder="admin">
+                    </div>
+                    <div class="form-group">
+                        <label class="form-label">REST Passwort</label>
+                        <input type="password" class="form-input" id="restAuthPassword" placeholder="Leer lassen = bestehendes Passwort behalten">
+                    </div>
+                    <div id="securityInfo" style="font-size:12px;color:var(--text-secondary);margin-top:8px"></div>
+                </div>
+            </div>
+
+            <div class="config-pane">
+                <div class="config-pane-title">System Init / RegLogin</div>
+                <div class="config-pane-body">
+                    <div style="font-size:13px;color:var(--text-secondary);line-height:1.45;margin-bottom:8px">
+                        Dieses globale Initial-Script wird dauerhaft gespeichert und beim Start/Connect geladen.
+                        Im Service-Modus läuft es nach erfolgreichem OPC-Connect/Reconnect, wenn <b>Nach OPC Connect</b> aktiv ist.
+                    </div>
+                    <div class="config-path" id="systemInitPathLabel">config/system-init-script.json</div>
+
+                    <div class="config-checkbox-row">
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="systemInitEnabled"> Aktiv
+                        </label>
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="systemInitRunAtProgramStart"> Bei Programmstart
+                        </label>
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="systemInitRunAfterConnect"> Nach OPC Connect/Reconnect
+                        </label>
+                    </div>
+
+                    <div class="config-actions">
+                        <button type="button" class="btn" onclick="insertRegLoginTemplate()">RegLogin Template einfügen</button>
+                        <button type="button" class="btn btn-success" onclick="saveSystemInit(true)">Speichern &amp; jetzt ausführen</button>
+                    </div>
+
+                    <label class="form-label">JavaScript</label>
+                    <textarea class="form-textarea js-editor" id="systemInitScript" placeholder="var response = http.postJson(&quot;http://localhost:9000/api/reglogin&quot;, { client: &quot;opcua-client&quot; });&#10;var result = JSON.parse(response.body);&#10;global.session = result;&#10;global.token = result.token;&#10;log.info(&quot;RegLogin OK&quot;);"></textarea>
+                    <div id="systemInitInfo" style="font-size:12px;color:var(--text-secondary);margin-top:10px"></div>
+                </div>
+            </div>
+
+            <div class="config-pane">
+                <div class="config-pane-title">Script Templates / Button-Vorlagen</div>
+                <div class="config-pane-body">
+                    <div style="font-size:13px;color:var(--text-secondary);line-height:1.45;margin-bottom:8px">
+                        GET, POST und SET sind nur Standard-Templates. Du kannst sie ändern, deaktivieren oder beliebig viele eigene Templates anlegen. Für jedes aktive Template wird im Dialog <b>Create New Action</b> automatisch ein Button erzeugt.
+                    </div>
+                    <div class="config-path" id="scriptTemplatePathLabel">config/script-templates.json</div>
+                    <div class="template-manager-grid">
+                        <div>
+                            <div id="scriptTemplateList" class="template-list"></div>
+                            <div style="display:flex;gap:6px;flex-wrap:wrap;margin-top:8px">
+                                <button type="button" class="btn btn-small" onclick="newScriptTemplate()">Neu</button>
+                                <button type="button" class="btn btn-small btn-secondary" onclick="deleteScriptTemplate()">Löschen</button>
+                                <button type="button" class="btn btn-small" onclick="resetScriptTemplates()">GET/POST/SET Reset</button>
+                            </div>
+                        </div>
+                        <div>
+                            <label class="form-label">Name / Button-Text</label>
+                            <input type="text" class="form-input" id="scriptTemplateName" placeholder="z. B. POST an MES">
+                            <label style="display:flex;gap:8px;align-items:center;margin:10px 0">
+                                <input type="checkbox" id="scriptTemplateEnabled" checked> Aktiv / Button anzeigen
+                            </label>
+                            <div style="display:flex;gap:6px;flex-wrap:wrap;margin-bottom:8px">
+                                <button type="button" class="btn btn-small" onclick="insertTemplatePlaceholders()">Platzhalter einfügen</button>
+                                <button type="button" class="btn btn-small btn-success" onclick="saveScriptTemplates()">Templates speichern</button>
+                            </div>
+                            <label class="form-label">JavaScript Template</label>
+                            <textarea class="form-textarea js-editor" id="scriptTemplateCode" placeholder="{{readNumberVars}}&#10;var response = http.postJson(&quot;http://localhost:9000/api/process&quot;, {&#10;{{payloadFields}}});&#10;var result = JSON.parse(response.body);&#10;global.apiResult = result;&#10;{{opcWritesFromResult}}"></textarea>
+                            <div style="font-size:12px;color:var(--text-secondary);margin-top:8px;line-height:1.45">
+                                Platzhalter: <code>{{readNumberVars}}</code>, <code>{{readTextVars}}</code>, <code>{{payloadFields}}</code>, <code>{{opcWritesFromResult}}</code>, <code>{{selectedNodesComment}}</code>, <code>{{firstNodeIdJs}}</code>, <code>{{firstAlias}}</code>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+            </div>
+
+            <div style="display:flex;gap:8px;justify-content:flex-end;flex-wrap:wrap">
+                <button class="btn" style="min-width:110px" onclick="saveConfiguration()">Save</button>
+                <button class="btn btn-secondary" style="min-width:110px" onclick="closeSystemInitModal()">Cancel</button>
+            </div>
+        </div>
+    </div>
+
+    <!-- Action Modal -->
+    <div class="modal" id="actionModal">
+        <div class="modal-content">
+            <div class="modal-header">Create Action</div>
+            <div class="form-group">
+                <label class="form-label">Name</label>
+                <input type="text" class="form-input" id="actionName" placeholder="Temperature Alert">
+            </div>
+            <div class="form-group">
+                <label class="form-label">Trigger Type</label>
+                <select class="form-select" id="triggerType" onchange="updateTriggerFields()">
+                    <option value="ON_CHANGE">On Change</option>
+                    <option value="ON_EVEN">On Even Number</option>
+                    <option value="ON_ODD">On Odd Number</option>
+                    <option value="ON_TRUE">On True</option>
+                    <option value="ON_FALSE">On False</option>
+                    <option value="ON_VALUE">On Specific Value</option>
+                    <option value="ON_GREATER_THAN">On Greater Than</option>
+                    <option value="ON_LESS_THAN">On Less Than</option>
+                    <option value="ON_INTERVAL">On Time Interval</option>
+                </select>
+            </div>
+            <div class="form-group" id="triggerValueGroup" style="display:none">
+                <label class="form-label">Trigger Value</label>
+                <input type="text" class="form-input" id="triggerValue" placeholder="e.g., 100">
+            </div>
+            <div class="form-group" id="intervalGroup" style="display:none">
+                <label class="form-label">Interval (ms)</label>
+                <input type="number" class="form-input" id="intervalMs" value="1000">
+            </div>
+            <div class="form-group">
+                <label class="form-label" style="display:flex;gap:8px;align-items:center">
+                    <input type="checkbox" id="initEnabled" onchange="toggleInitConfig()">
+                    Initial-Call / Session aktivieren
+                </label>
+                <div id="initConfig" style="display:none;margin-top:10px">
+                    <div style="font-size:12px;color:var(--text-secondary);margin-bottom:6px">Läuft beim Programmstart und nach Connect-Klick. Geeignet für RegLogin, Token, Session-ID und globale API-Ergebnisse.</div>
+                    <textarea class="form-textarea js-editor" id="initScript" placeholder="var login = http.postJson(&quot;http://localhost:9000/api/login&quot;, { user: &quot;opc&quot;, password: &quot;secret&quot; });&#10;var result = JSON.parse(login.body);&#10;session.token = result.token;&#10;global.session = result;&#10;global.lastLogin = result;"></textarea>
+                </div>
+            </div>
+            <div class="form-group">
+                <label class="form-label" style="display:flex;gap:8px;align-items:center">
+                    <input type="checkbox" id="conditionEnabled" onchange="toggleConditionConfig()">
+                    Bedingung aktivieren
+                </label>
+                <div id="conditionConfig" style="display:none;margin-top:10px">
+                    <label class="form-label">NodeID-Codebausteine einfügen</label>
+                    <div style="font-size:12px;color:var(--text-secondary);margin-bottom:6px">Die Liste erzeugt nur Code. Beim Speichern ist das Script vollständig eigenständig, z. B. <code>var Temperatur = opc.read(&quot;ns=...&quot;)</code>.</div>
+<div id="conditionNodeList" class="code-helper-list"></div>
+                    <label class="form-label" style="margin-top:10px">Condition JavaScript (muss true/false zurückgeben)</label>
+                    <textarea class="form-textarea js-editor" id="conditionScript" placeholder="var Temperatur = Number(opc.read(&quot;ns=3;s=AirConditioner_1.Temperature&quot;));&#10;Temperatur &gt; 70"></textarea>
+                </div>
+            </div>
+            <div class="form-group">
+                <label class="form-label">NodeID-Codegenerator fuer Hauptscript</label>
+                <div class="code-helper">
+                    <div style="font-size:12px;color:var(--text-secondary)">Checkboxen erzeugen nur feste Codezeilen. Es werden keine Runtime-Variablen aus Checkboxen gespeichert.</div>
+                    <div id="actionNodeCodeList" class="code-helper-list"></div>
+                    <div style="display:flex;gap:6px;flex-wrap:wrap">
+                        <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('actionNodeCodeList','scriptCode','readNumber')">var Number einfuegen</button>
+                        <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('actionNodeCodeList','scriptCode','read')">var Text einfuegen</button>
+                        <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('actionNodeCodeList','scriptCode','write','result.value')">opc.write einfuegen</button>
+                    </div>
+                    <div id="actionTemplateButtons" style="display:flex;gap:6px;flex-wrap:wrap;margin-top:6px"></div>
+                </div>
+                <label class="form-label">JavaScript Code</label>
+                <textarea class="form-textarea js-editor" id="scriptCode" placeholder="var Temperatur = Number(opc.read(&quot;ns=3;s=AirConditioner_1.Temperature&quot;));&#10;var response = http.postJson(&quot;http://localhost:9000/api/check&quot;, { temperature: Temperatur });&#10;var result = JSON.parse(response.body);&#10;opc.write(&quot;ns=3;s=AirConditioner_1.Result&quot;, result.value);"></textarea>
+            </div>
+            <div style="display:flex;gap:8px">
+                <button class="btn" style="flex:1" onclick="saveAction()">Save</button>
+                <button class="btn btn-secondary" style="flex:1" onclick="closeModal()">Cancel</button>
+            </div>
+        </div>
+    </div>
+
+    <!-- Edit Value Modal -->
+    <div class="modal" id="editValueModal">
+        <div class="modal-content">
+            <div class="modal-header">Edit Value</div>
+            <div class="form-group">
+                <label class="form-label">Node ID</label>
+                <input type="text" class="form-input" id="editNodeId" readonly>
+            </div>
+            <div class="form-group">
+                <label class="form-label">New Value</label>
+                <input type="text" class="form-input" id="editValue">
+            </div>
+            <div style="display:flex;gap:8px">
+                <button class="btn btn-success" style="flex:1" onclick="writeValue()">Write</button>
+                <button class="btn btn-secondary" style="flex:1" onclick="closeEditValueModal()">Cancel</button>
+            </div>
+        </div>
+    </div>
+
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.16/codemirror.min.js"></script>
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.16/mode/javascript/javascript.min.js"></script>
+    <script>
+        const API = window.location.origin + '/api';
+        let nodes = [], actions = [], systemInitConfig = {}, scriptTemplates = [], securityConfig = {}, selectedTemplateIndex = -1, isConnected = false, currentNodeForAction = null, autoRefreshInterval = null;
+        let restAuth = { enabled: false, user: 'admin', password: sessionStorage.getItem('opcuaRestPassword') || '' };
+        const jsEditors = {};
+
+        function buildAuthHeaders() {
+            if (!restAuth.enabled || !restAuth.password) return {};
+            return { 'Authorization': 'Basic ' + btoa((restAuth.user || 'admin') + ':' + restAuth.password) };
+        }
+
+        async function apiFetch(path, options = {}) {
+            options.headers = Object.assign({}, options.headers || {}, buildAuthHeaders());
+            let response = await fetch(API + path, options);
+            if (response.status === 401) {
+                const pw = prompt('REST Passwort für Benutzer ' + (restAuth.user || 'admin') + ':');
+                if (pw === null) return response;
+                restAuth.password = pw;
+                sessionStorage.setItem('opcuaRestPassword', pw);
+                options.headers = Object.assign({}, options.headers || {}, buildAuthHeaders());
+                response = await fetch(API + path, options);
+            }
+            return response;
+        }
+
+        async function loadAuthStatus() {
+            try {
+                const d = await (await fetch(API + '/auth/status')).json();
+                restAuth.enabled = !!d.restAuthEnabled;
+                restAuth.user = d.restAuthUser || 'admin';
+            } catch(e) {}
+        }
+
+        // ── Status polling ────────────────────────────────────────────────────
+        setInterval(checkStatus, 5000);
+        loadAuthStatus().then(() => { checkStatus(); loadActions(); loadSystemInit(); loadScriptTemplates(); });
+        checkStatus();
+        setInterval(pollTwinStatus, 4000);
+
+        async function checkStatus() {
+            try {
+                const d = await (await apiFetch('/status')).json();
+                isConnected = d.connected;
+                document.getElementById('statusDot').classList.toggle('connected', isConnected);
+                document.getElementById('statusText').textContent = isConnected ? 'Connected' : 'Disconnected';
+            } catch(e) { isConnected = false; }
+        }
+
+        async function pollTwinStatus() {
+            try {
+                const d = await (await apiFetch('/twin-status')).json();
+                const el = document.getElementById('twinStatus');
+                if (d.ready) {
+                    el.textContent = '✅ Export bereit (' + d.nodeCount + ' Nodes)';
+                } else if (d.building) {
+                    el.textContent = '⏳ Export wird gebaut…';
+                } else {
+                    el.textContent = '';
+                }
+            } catch(e) {}
+        }
+
+        // ── Tree: lazy browse ─────────────────────────────────────────────────
+        async function loadRoot() {
+            if (!isConnected) { alert('Not connected'); return; }
+            const btn = document.getElementById('loadTreeBtn');
+            btn.disabled = true;
+            const container = document.getElementById('treeView');
+            container.innerHTML = '<div style="padding:20px;text-align:center"><span class="spinner"></span> Loading…</div>';
+
+            try {
+                const d = await browseNode(null);
+                container.innerHTML = '';
+                container.appendChild(buildUl(d.children));
+                document.getElementById('treeInfo').textContent = d.children.length + ' root nodes';
+            } catch(e) {
+                container.innerHTML = '<div class="empty-state"><div>Error: ' + e.message + '</div></div>';
+            } finally {
+                btn.disabled = false;
+            }
+        }
+
+        async function browseNode(nodeId) {
+            const r = await apiFetch('/browse-tree', {
+                method: 'POST',
+                headers: {'Content-Type': 'application/json'},
+                body: JSON.stringify(nodeId ? {nodeId} : {})
+            });
+            const d = await r.json();
+            if (!d.success) throw new Error(d.error || 'Browse failed');
+            return d;
+        }
+
+        function buildUl(children) {
+            const ul = document.createElement('div');
+            for (const n of children) {
+                const wrap = document.createElement('div');
+
+                const row = document.createElement('div');
+                row.className = 'tree-node';
+
+                const content = document.createElement('div');
+                content.className = 'tree-node-content';
+
+                // Expand button
+                const expand = document.createElement('div');
+                expand.className = 'tree-expand';
+                expand.textContent = '›';
+                expand.onclick = async (e) => {
+                    e.stopPropagation();
+                    const childContainer = wrap.querySelector('.tree-children');
+                    if (childContainer.classList.contains('show')) {
+                        childContainer.classList.remove('show');
+                        expand.classList.remove('expanded');
+                        return;
+                    }
+                    // Lazy load children
+                    if (childContainer.children.length === 0) {
+                        expand.classList.add('loading-spin');
+                        expand.textContent = '○';
+                        try {
+                            const d = await browseNode(n.nodeId);
+                            if (d.children.length > 0) {
+                                childContainer.appendChild(buildUl(d.children));
+                            } else {
+                                childContainer.innerHTML = '<div style="padding:8px 16px;font-size:12px;color:var(--text-secondary)">No children</div>';
+                            }
+                        } catch(err) {
+                            childContainer.innerHTML = '<div style="padding:8px;color:var(--red)">Error loading</div>';
+                        }
+                        expand.classList.remove('loading-spin');
+                        expand.textContent = '›';
+                    }
+                    childContainer.classList.add('show');
+                    expand.classList.add('expanded');
+                };
+
+                const isVar = n.nodeClass === 'Variable';
+                const icon = isVar ? '📊' : (n.nodeClass === 'View' ? '👁' : '📁');
+
+                const label = document.createElement('span');
+                label.style.flex = '1';
+                label.innerHTML = `<span style="margin-right:6px">${icon}</span><b>${esc(n.displayName || n.browseName)}</b><span style="font-size:11px;color:var(--text-secondary);margin-left:6px">${n.nodeClass || ''}</span>`;
+
+                // Value badge for Variables
+                if (isVar && n.value != null) {
+                    const badge = document.createElement('span');
+                    badge.className = 'value-badge';
+                    badge.textContent = n.value;
+                    label.appendChild(badge);
+                }
+
+                // Click to add to monitoring
+                label.onclick = () => addNode(n.nodeId, n.displayName || n.browseName);
+                label.style.cursor = 'pointer';
+
+                content.appendChild(expand);
+                content.appendChild(label);
+                row.appendChild(content);
+
+                const childContainer = document.createElement('div');
+                childContainer.className = 'tree-children';
+
+                wrap.appendChild(row);
+                wrap.appendChild(childContainer);
+                ul.appendChild(wrap);
+            }
+            return ul;
+        }
+
+        // ── Monitoring table ──────────────────────────────────────────────────
+        function addNode(nodeId, name) {
+            if (nodes.find(n => n.id === nodeId)) { alert('Already added'); return; }
+            const m = nodeId.match(/ns=(\d+);([a-z])=/i);
+            nodes.push({
+                id: nodeId, name,
+                ns:   m ? m[1] : '?',
+                type: m ? (m[2].toLowerCase() === 's' ? 'String' : 'UInteger') : '?',
+                value: '…'
+            });
+            renderTable();
+            readValue(nodeId);
+        }
+
+        async function readValue(nodeId) {
+            try {
+                const d = await (await apiFetch('/read', {
+                    method: 'POST',
+                    headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId})
+                })).json();
+                if (d.success) {
+                    const n = nodes.find(x => x.id === nodeId);
+                    if (n) {
+                        const cell = document.querySelector(`[data-node-id="${nodeId}"] .value-cell`);
+                        if (cell && n.value !== d.value) {
+                            cell.classList.add('updating');
+                            setTimeout(() => cell.classList.remove('updating'), 500);
+                        }
+                        n.value = d.value;
+                        renderTable();
+                    }
+                }
+            } catch(e) {}
+        }
+
+        function renderTable() {
+            const tb = document.getElementById('nodesTableBody');
+            document.getElementById('nodeCount').textContent = nodes.length;
+            if (nodes.length === 0) {
+                tb.innerHTML = '<tr><td colspan="7"><div class="empty-state"><div class="empty-icon">📊</div><div>No nodes — click a tree node to add</div></div></td></tr>';
+                return;
+            }
+            tb.innerHTML = nodes.map((n, i) => `
+                <tr data-node-id="${esc(n.id)}">
+                    <td style="font-weight:600">${esc(n.name)}</td>
+                    <td style="font-size:12px;color:var(--text-secondary)">${esc(n.id)}</td>
+                    <td><span class="badge">${n.ns}</span></td>
+                    <td><span class="badge badge-warning">${n.type}</span></td>
+                    <td><span class="value-cell" onclick="editVal('${esc(n.id)}','${esc(n.value)}')">${esc(n.value)}</span></td>
+                    <td><button class="btn btn-small" onclick="openActions('${esc(n.id)}')">Actions</button></td>
+                    <td><button class="btn-delete" onclick="removeNode(${i})">×</button></td>
+                </tr>`).join('');
+        }
+
+        function removeNode(idx) {
+            if (confirm('Remove ' + nodes[idx].name + '?')) { nodes.splice(idx, 1); renderTable(); }
+        }
+
+        function toggleAutoRefresh() {
+            if (autoRefreshInterval) {
+                clearInterval(autoRefreshInterval);
+                autoRefreshInterval = null;
+                document.getElementById('refreshLabel').textContent = '▶ Live';
+            } else {
+                autoRefreshInterval = setInterval(() => nodes.forEach(n => readValue(n.id)), 2000);
+                document.getElementById('refreshLabel').textContent = '⏹ Stop';
+                nodes.forEach(n => readValue(n.id));
+            }
+        }
+
+        // ── Export ────────────────────────────────────────────────────────────
+        function exportTwin() {
+            window.open(API + '/export', '_blank');
+        }
+
+        // ── Write value ───────────────────────────────────────────────────────
+        function editVal(nodeId, val) {
+            document.getElementById('editNodeId').value = nodeId;
+            document.getElementById('editValue').value = val;
+            document.getElementById('editValueModal').classList.add('active');
+        }
+        function closeEditValueModal() { document.getElementById('editValueModal').classList.remove('active'); }
+
+        async function writeValue() {
+            const nodeId = document.getElementById('editNodeId').value;
+            const value  = document.getElementById('editValue').value;
+            try {
+                const d = await (await apiFetch('/write', {
+                    method: 'POST',
+                    headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId, value})
+                })).json();
+                if (d.success) {
+                    const n = nodes.find(x => x.id === nodeId);
+                    if (n) { n.value = value; renderTable(); }
+                    closeEditValueModal();
+                } else alert('Write failed');
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        // ── System Init / RegLogin ──────────────────────────────────────────────
+        async function loadSecurityConfig() {
+            try {
+                const d = await (await apiFetch('/config/security')).json();
+                if (d.success) {
+                    securityConfig = d;
+                    const dir = document.getElementById('configDirectoryLabel');
+                    const settings = document.getElementById('settingsFileLabel');
+                    if (dir) dir.textContent = d.configDirectory || 'config';
+                    if (settings) settings.textContent = d.settingsFile || 'config/settings.json';
+                    const enc = document.getElementById('configEncryptionEnabled');
+                    const rp = document.getElementById('restAuthEnabled');
+                    const ru = document.getElementById('restAuthUser');
+                    if (enc) enc.checked = !!d.configEncryptionEnabled;
+                    if (rp) rp.checked = !!d.restAuthEnabled;
+                    if (ru) ru.value = d.restAuthUser || 'admin';
+                    const info = document.getElementById('securityInfo');
+                    if (info) info.textContent = 'REST Passwort gesetzt: ' + (d.restAuthPasswordSet ? 'ja' : 'nein') + ' · Config Passwort gesetzt: ' + (d.configEncryptionPasswordSet ? 'ja' : 'nein');
+                }
+            } catch(e) {
+                const info = document.getElementById('securityInfo');
+                if (info) info.textContent = 'Security-Config konnte nicht geladen werden: ' + e.message;
+            }
+        }
+
+        async function saveSecurityConfig() {
+            const payload = {
+                configEncryptionEnabled: document.getElementById('configEncryptionEnabled')?.checked || false,
+                configEncryptionPassword: document.getElementById('configEncryptionPassword')?.value || '',
+                restAuthEnabled: document.getElementById('restAuthEnabled')?.checked || false,
+                restAuthUser: document.getElementById('restAuthUser')?.value || 'admin',
+                restAuthPassword: document.getElementById('restAuthPassword')?.value || ''
+            };
+            const d = await (await apiFetch('/config/security', {
+                method: 'POST',
+                headers: {'Content-Type': 'application/json'},
+                body: JSON.stringify(payload)
+            })).json();
+            if (!d.success) throw new Error(d.error || 'Security speichern fehlgeschlagen');
+            securityConfig = d;
+            restAuth.enabled = !!d.restAuthEnabled && !!d.restAuthPasswordSet;
+            restAuth.user = d.restAuthUser || 'admin';
+            const pw = payload.restAuthPassword;
+            if (pw) {
+                restAuth.password = pw;
+                sessionStorage.setItem('opcuaRestPassword', pw);
+            }
+            document.getElementById('restAuthPassword').value = '';
+            document.getElementById('configDirectoryLabel').textContent = d.configDirectory || 'config';
+            document.getElementById('settingsFileLabel').textContent = d.settingsFile || 'config/settings.json';
+            document.getElementById('securityInfo').textContent = 'Gespeichert. REST Auth: ' + (restAuth.enabled ? 'aktiv' : 'aus');
+        }
+
+        async function loadSystemInit() {
+            try {
+                const d = await (await apiFetch('/system-init')).json();
+                if (d.success) systemInitConfig = Object.assign({}, d.config || {}, {file: d.file});
+            } catch(e) {}
+        }
+
+        async function openConfigurationModal() {
+            await loadAuthStatus();
+            await loadSecurityConfig();
+            await loadSystemInit();
+            await loadScriptTemplates();
+            document.getElementById('systemInitEnabled').checked = !!systemInitConfig.enabled;
+            document.getElementById('systemInitRunAtProgramStart').checked = !!systemInitConfig.runAtProgramStart;
+            document.getElementById('systemInitRunAfterConnect').checked = systemInitConfig.runAfterConnect !== false;
+            setEditorValue('systemInitScript', systemInitConfig.script || '');
+            document.getElementById('systemInitPathLabel').textContent = systemInitConfig.file || 'config/system-init-script.json';
+            document.getElementById('systemInitInfo').textContent = systemInitConfig.updatedAt ? ('Zuletzt gespeichert: ' + new Date(systemInitConfig.updatedAt).toLocaleString()) : '';
+            document.getElementById('systemInitModal').classList.add('active');
+            ensureEditor('systemInitScript');
+            ensureEditor('scriptTemplateCode');
+            renderScriptTemplateList();
+            setTimeout(() => { 
+                if (jsEditors.systemInitScript) jsEditors.systemInitScript.refresh();
+                if (jsEditors.scriptTemplateCode) jsEditors.scriptTemplateCode.refresh();
+            }, 50);
+        }
+
+        function insertRegLoginTemplate() {
+            insertAtCursor('systemInitScript', `var response = http.postJson("http://localhost:9000/api/reglogin", {
+  client: "opcua-client",
+  user: "opc",
+  password: "secret"
+});
+
+if (response.status < 200 || response.status >= 300) {
+  throw "RegLogin failed: HTTP " + response.status + " / " + response.body;
+}
+
+var result = JSON.parse(response.body);
+global.session = result;
+global.token = result.token;
+global.apiResult = result;
+log.info("RegLogin OK");
+`);
+        }
+
+        async function saveConfiguration() {
+            try { await saveSecurityConfig(); } catch(e) { alert('Security speichern Fehler: ' + e.message); return; }
+            await saveSystemInit(false);
+            await saveScriptTemplates(false);
+            closeSystemInitModal();
+        }
+
+        function closeSystemInitModal() {
+            document.getElementById('systemInitModal').classList.remove('active');
+        }
+
+        async function saveSystemInit(runAfterSave) {
+            const payload = {
+                enabled: document.getElementById('systemInitEnabled').checked,
+                runAtProgramStart: document.getElementById('systemInitRunAtProgramStart').checked,
+                runAfterConnect: document.getElementById('systemInitRunAfterConnect').checked,
+                script: getEditorValue('systemInitScript')
+            };
+            try {
+                const d = await (await apiFetch('/system-init', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify(payload)
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Save failed');
+                systemInitConfig = Object.assign({}, d.config || payload, {file: d.file});
+                const file = d.file || 'config/system-init-script.json';
+                document.getElementById('systemInitPathLabel').textContent = file;
+                document.getElementById('systemInitInfo').textContent = 'Gespeichert in: ' + file;
+                if (runAfterSave) await runSystemInit();
+            } catch(e) { alert('System Init Fehler: ' + e.message); }
+        }
+
+        async function runSystemInit() {
+            try {
+                const d = await (await apiFetch('/system-init/run', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({reason: 'manual-ui', force: true})
+                })).json();
+                if (!d.success && !d.skipped) throw new Error(d.error || 'Run failed');
+                document.getElementById('systemInitInfo').textContent = d.skipped
+                    ? ('Nicht ausgeführt: ' + (d.message || 'skipped'))
+                    : ('Ausgeführt. Globals: ' + JSON.stringify(d.globals || {}));
+            } catch(e) { alert('System Init Run Fehler: ' + e.message); }
+        }
+
+
+        // ── Script Templates ───────────────────────────────────────────────────
+        async function loadScriptTemplates() {
+            try {
+                const d = await (await apiFetch('/script/templates')).json();
+                if (d.success) {
+                    scriptTemplates = d.templates || [];
+                    const path = document.getElementById('scriptTemplatePathLabel');
+                    if (path) path.textContent = d.file || 'config/script-templates.json';
+                }
+            } catch(e) {}
+        }
+
+        function commitSelectedTemplate() {
+            if (selectedTemplateIndex < 0 || selectedTemplateIndex >= scriptTemplates.length) return;
+            const t = scriptTemplates[selectedTemplateIndex];
+            const nameEl = document.getElementById('scriptTemplateName');
+            const enabledEl = document.getElementById('scriptTemplateEnabled');
+            if (nameEl) t.name = nameEl.value || 'Template';
+            if (enabledEl) t.enabled = !!enabledEl.checked;
+            t.script = getEditorValue('scriptTemplateCode');
+            t.updatedAt = Date.now();
+        }
+
+        function renderScriptTemplateList() {
+            const list = document.getElementById('scriptTemplateList');
+            if (!list) return;
+            if (!scriptTemplates.length) {
+                list.innerHTML = '<div style="padding:12px;color:var(--text-secondary)">Keine Templates vorhanden.</div>';
+                selectedTemplateIndex = -1;
+                setTemplateForm(null);
+                return;
+            }
+            if (selectedTemplateIndex < 0 || selectedTemplateIndex >= scriptTemplates.length) selectedTemplateIndex = 0;
+            list.innerHTML = scriptTemplates.map((t, i) => `
+                <div class="template-list-item ${i === selectedTemplateIndex ? 'active' : ''}" onclick="selectScriptTemplate(${i})">
+                    <span>${t.enabled === false ? '○' : '●'} ${esc(t.name || 'Template')}</span>
+                    <span style="color:var(--text-secondary);font-size:11px">${t.builtIn ? 'Standard' : 'Eigen'}</span>
+                </div>`).join('');
+            setTemplateForm(scriptTemplates[selectedTemplateIndex]);
+        }
+
+        function setTemplateForm(t) {
+            const nameEl = document.getElementById('scriptTemplateName');
+            const enabledEl = document.getElementById('scriptTemplateEnabled');
+            if (nameEl) nameEl.value = t ? (t.name || '') : '';
+            if (enabledEl) enabledEl.checked = !t || t.enabled !== false;
+            setEditorValue('scriptTemplateCode', t ? (t.script || '') : '');
+        }
+
+        function selectScriptTemplate(index) {
+            commitSelectedTemplate();
+            selectedTemplateIndex = index;
+            renderScriptTemplateList();
+            if (jsEditors.scriptTemplateCode) setTimeout(() => jsEditors.scriptTemplateCode.refresh(), 20);
+        }
+
+        function newScriptTemplate() {
+            commitSelectedTemplate();
+            scriptTemplates.push({
+                id: '', name: 'Neues Template', enabled: true, builtIn: false, updatedAt: Date.now(),
+                script: `// Eigenes Template\n// Die Platzhalter werden beim Einfügen durch feste NodeID-Codezeilen ersetzt.\n{{readNumberVars}}\n\nvar response = http.postJson("http://localhost:9000/api/process", {\n{{payloadFields}}});\n\nvar result = JSON.parse(response.body);\nglobal.apiResult = result;\n{{opcWritesFromResult}}\n`
+            });
+            selectedTemplateIndex = scriptTemplates.length - 1;
+            renderScriptTemplateList();
+        }
+
+        function deleteScriptTemplate() {
+            if (selectedTemplateIndex < 0) return;
+            if (!confirm('Template löschen?')) return;
+            scriptTemplates.splice(selectedTemplateIndex, 1);
+            selectedTemplateIndex = Math.min(selectedTemplateIndex, scriptTemplates.length - 1);
+            renderScriptTemplateList();
+        }
+
+        async function resetScriptTemplates() {
+            if (!confirm('Standard GET/POST/SET wiederherstellen? Eigene Template-Änderungen werden ersetzt.')) return;
+            try {
+                const d = await (await apiFetch('/script/templates', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify({resetDefaults: true})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Reset failed');
+                scriptTemplates = d.templates || [];
+                selectedTemplateIndex = 0;
+                renderScriptTemplateList();
+                renderActionTemplateButtons();
+            } catch(e) { alert('Template Reset Fehler: ' + e.message); }
+        }
+
+        async function saveScriptTemplates(showMessage = true) {
+            commitSelectedTemplate();
+            try {
+                const d = await (await apiFetch('/script/templates', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify({templates: scriptTemplates})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Save failed');
+                scriptTemplates = d.templates || [];
+                renderScriptTemplateList();
+                renderActionTemplateButtons();
+                if (showMessage) alert('Templates gespeichert');
+            } catch(e) { alert('Templates speichern Fehler: ' + e.message); }
+        }
+
+        function insertTemplatePlaceholders() {
+            insertAtCursor('scriptTemplateCode', `\n// Platzhalter:\n{{readNumberVars}}\n{{payloadFields}}\n{{opcWritesFromResult}}\n`);
+        }
+
+        async function renderActionTemplateButtons() {
+            const box = document.getElementById('actionTemplateButtons');
+            if (!box) return;
+            if (!scriptTemplates.length) await loadScriptTemplates();
+            const active = scriptTemplates.filter(t => t.enabled !== false);
+            if (!active.length) {
+                box.innerHTML = '<span style="font-size:12px;color:var(--text-secondary)">Keine aktiven Templates. Unter Configuration → Script Templates anlegen.</span>';
+                return;
+            }
+            box.innerHTML = active.map(t => `<button type="button" class="btn btn-small" onclick="insertUserTemplate('${escAttr(t.id || t.name)}')">${esc(t.name || 'Template')}</button>`).join('');
+        }
+
+        async function insertUserTemplate(templateId) {
+            const selected = getCheckedNodeSpecs('actionNodeCodeList');
+            try {
+                const d = await (await apiFetch('/script/template-snippet', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({templateId, nodes: selected})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Template failed');
+                insertAtCursor('scriptCode', d.script);
+            } catch(e) { alert('Template Fehler: ' + e.message); }
+        }
+
+        // ── Actions ───────────────────────────────────────────────────────────
+        async function openActions(nodeId) {
+            currentNodeForAction = nodeId;
+            await loadScriptTemplates();
+            renderConditionNodeList();
+            renderNodeCodeList('actionNodeCodeList');
+            renderActionTemplateButtons();
+            document.getElementById('actionModal').classList.add('active');
+            ['initScript','conditionScript','scriptCode'].forEach(ensureEditor);
+        }
+        function closeModal() { document.getElementById('actionModal').classList.remove('active'); }
+
+        function updateTriggerFields() {
+            const t = document.getElementById('triggerType').value;
+            document.getElementById('triggerValueGroup').style.display =
+                ['ON_VALUE','ON_GREATER_THAN','ON_LESS_THAN'].includes(t) ? 'block' : 'none';
+            document.getElementById('intervalGroup').style.display =
+                t === 'ON_INTERVAL' ? 'block' : 'none';
+        }
+
+        function toggleConditionConfig() {
+            document.getElementById('conditionConfig').style.display =
+                document.getElementById('conditionEnabled').checked ? 'block' : 'none';
+        }
+
+        function toggleInitConfig() {
+            document.getElementById('initConfig').style.display =
+                document.getElementById('initEnabled').checked ? 'block' : 'none';
+        }
+
+        function renderConditionNodeList() {
+            renderNodeCodeList('conditionNodeList');
+            const box = document.getElementById('conditionNodeList');
+            if (box && nodes.length) {
+                const buttons = document.createElement('div');
+                buttons.style.display = 'flex';
+                buttons.style.gap = '6px';
+                buttons.style.flexWrap = 'wrap';
+                buttons.style.marginTop = '8px';
+                buttons.innerHTML = `
+                    <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('conditionNodeList','conditionScript','readNumber')">var Number in Bedingung</button>
+                    <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('conditionNodeList','conditionScript','read')">var Text in Bedingung</button>`;
+                box.appendChild(buttons);
+            }
+        }
+
+        function renderNodeCodeList(containerId) {
+            const box = document.getElementById(containerId);
+            if (!box) return;
+            if (!nodes.length) {
+                box.innerHTML = '<div style="font-size:12px;color:var(--text-secondary)">Keine ueberwachten Nodes vorhanden.</div>';
+                return;
+            }
+            box.innerHTML = nodes.map((n, i) => {
+                const alias = safeAlias(n.name || n.id);
+                return `<label class="code-helper-row">
+                    <input type="checkbox" data-node-id="${esc(n.id)}" checked>
+                    <input class="code-helper-alias" value="${esc(alias)}" title="Variablenname im erzeugten Script">
+                    <span style="font-size:11px;color:var(--text-secondary);overflow:hidden;text-overflow:ellipsis">${esc(n.id)}</span>
+                </label>`;
+            }).join('');
+        }
+
+        function getCheckedNodeSpecs(containerId) {
+            const box = document.getElementById(containerId);
+            if (!box) return [];
+            return [...box.querySelectorAll('input[type="checkbox"][data-node-id]:checked')].map(cb => {
+                const row = cb.closest('.code-helper-row');
+                const aliasInput = row ? row.querySelector('.code-helper-alias') : null;
+                return { nodeId: cb.dataset.nodeId, alias: aliasInput ? aliasInput.value : undefined };
+            });
+        }
+
+        async function insertCheckedNodeSnippets(containerId, targetId, mode, writeExpression) {
+            const selected = getCheckedNodeSpecs(containerId);
+            if (!selected.length) { alert('Keine Node markiert'); return; }
+            try {
+                const d = await (await apiFetch('/script/snippet', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({mode, nodes: selected, writeExpression})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Snippet failed');
+                insertAtCursor(targetId, d.script);
+            } catch(e) {
+                alert('Snippet Fehler: ' + e.message);
+            }
+        }
+
+        function selectedConditionNodes() {
+            // Keinen Runtime-Zustand aus Checkboxen speichern. Die NodeIDs stehen explizit im Script.
+            return {ids: [], aliases: {}};
+        }
+
+        function insertNodeSnippet(btn) {
+            const target = btn.dataset.target;
+            const nodeId = btn.dataset.nodeId;
+            const alias = safeAlias(btn.dataset.alias || nodeId);
+            let snippet;
+            if (btn.dataset.mode === 'readNumber') {
+                snippet = `var ${alias} = Number(opc.read(${JSON.stringify(nodeId)}));\n`;
+            } else if (btn.dataset.mode === 'write') {
+                snippet = `opc.write(${JSON.stringify(nodeId)}, /* value */);\n`;
+            } else {
+                snippet = `var ${alias} = opc.read(${JSON.stringify(nodeId)});\n`;
+            }
+            insertAtCursor(target, snippet);
+        }
+
+        function ensureEditor(id) {
+            const el = document.getElementById(id);
+            if (!el || jsEditors[id]) return jsEditors[id];
+            if (window.CodeMirror) {
+                jsEditors[id] = CodeMirror.fromTextArea(el, {
+                    mode: 'javascript', theme: 'material-darker', lineNumbers: true,
+                    lineWrapping: false, indentUnit: 2, tabSize: 2
+                });
+            }
+            return jsEditors[id];
+        }
+
+        function getEditorValue(id) {
+            return jsEditors[id] ? jsEditors[id].getValue() : (document.getElementById(id)?.value || '');
+        }
+
+        function setEditorValue(id, value) {
+            if (jsEditors[id]) jsEditors[id].setValue(value || '');
+            else { const el = document.getElementById(id); if (el) el.value = value || ''; }
+        }
+
+        function insertAtCursor(elementId, text) {
+            const cm = jsEditors[elementId];
+            if (cm) {
+                cm.replaceSelection(text);
+                cm.focus();
+                return;
+            }
+            const el = document.getElementById(elementId);
+            if (!el) return;
+            const start = el.selectionStart ?? el.value.length;
+            const end = el.selectionEnd ?? el.value.length;
+            el.value = el.value.slice(0, start) + text + el.value.slice(end);
+            const pos = start + text.length;
+            el.focus();
+            el.setSelectionRange(pos, pos);
+        }
+
+        async function loadActions() {
+            try {
+                const d = await (await apiFetch('/actions')).json();
+                if (d.success) {
+                    actions = d.actions || [];
+                    renderActions();
+                }
+            } catch(e) {}
+        }
+
+        async function saveAction() {
+            const a = {
+                nodeId:   currentNodeForAction,
+                name:     document.getElementById('actionName').value,
+                trigger:  document.getElementById('triggerType').value,
+                value:    document.getElementById('triggerValue').value,
+                interval: document.getElementById('intervalMs').value,
+                initEnabled: document.getElementById('initEnabled').checked,
+                initScript: getEditorValue('initScript'),
+                conditionEnabled: document.getElementById('conditionEnabled').checked,
+                conditionScript: getEditorValue('conditionScript'),
+                conditionNodeIds: [],
+                nodeAliases: {},
+                script:   getEditorValue('scriptCode')
+            };
+            if (!a.name || !a.script) { alert('Name and Script required!'); return; }
+            try {
+                const d = await (await apiFetch('/actions', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify(a)
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Save action failed');
+                await loadActions();
+                closeModal();
+                document.getElementById('actionName').value = '';
+                setEditorValue('scriptCode', '');
+                setEditorValue('initScript', '');
+                document.getElementById('initEnabled').checked = false;
+                toggleInitConfig();
+                setEditorValue('conditionScript', '');
+                document.getElementById('conditionEnabled').checked = false;
+                toggleConditionConfig();
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        function renderActions() {
+            const al = document.getElementById('actionsList');
+            document.getElementById('actionCount').textContent = actions.length;
+            if (actions.length === 0) {
+                al.innerHTML = '<div class="empty-state"><div class="empty-icon">⚡</div><div>No actions</div></div>';
+                return;
+            }
+            al.innerHTML = actions.map((a, i) => `
+                <div class="list-item">
+                    <div>
+                        <div style="font-weight:600">${esc(a.actionName || a.name)}</div>
+                        <div style="font-size:12px;color:var(--text-secondary);margin-top:4px">
+                            ${esc(a.triggerType || a.trigger)} · ${esc(a.nodeId || '')}
+                            ${a.initEnabled ? ' · init/session' : ''}
+                            ${a.conditionEnabled ? ' · condition' : ''}
+                        </div>
+                    </div>
+                    <div style="display:flex;gap:6px">
+                        <button class="btn btn-small" onclick="testAction(${i})">Test</button>
+                        <button class="btn-delete" onclick="deleteAction(${i})">×</button>
+                    </div>
+                </div>`).join('');
+        }
+
+        async function testAction(i) {
+            const a = actions[i];
+            try {
+                const d = await (await apiFetch('/actions/test', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId: a.nodeId, actionName: a.actionName || a.name, value: 'TEST'})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Test failed');
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        async function deleteAction(i) {
+            const a = actions[i];
+            if (!confirm('Delete: ' + (a.actionName || a.name) + '?')) return;
+            try {
+                const d = await (await apiFetch('/actions/delete', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId: a.nodeId, actionName: a.actionName || a.name})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Delete failed');
+                await loadActions();
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        function safeAlias(s) {
+            s = (s || 'node').toString().replace(/[^A-Za-z0-9_$]/g, '_');
+            return /^[A-Za-z_$]/.test(s) ? s : 'n_' + s;
+        }
+
+        function esc(s) {
+            if (!s) return '';
+            return s.toString().replace(/[&<>"']/g, m =>
+                ({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;',"'":'&#039;'}[m]));
+        }
+
+        function escAttr(s) {
+            return esc(s).replace(/`/g, '&#096;');
+        }
+    </script>
+</body>
+</html>
\ No newline at end of file
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diff --git a/target/classes/styles/application.css b/target/classes/styles/application.css
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index 0000000..c4c70ec
--- /dev/null
+++ b/target/classes/styles/application.css
@@ -0,0 +1,454 @@
+/* OPCUA GUI Stylesheet */
+/* Place this in src/main/resources/styles/application.css */
+
+/* ============================================================================
+   ROOT & GENERAL
+   ============================================================================ */
+.root {
+    -fx-font-family: "Segoe UI", Arial, sans-serif;
+    -fx-font-size: 13px;
+    -fx-base: #f4f4f4;
+    -fx-background: #ffffff;
+}
+
+/* ============================================================================
+   ACTION BUTTONS
+   ============================================================================ */
+.action-button {
+    -fx-background-color: linear-gradient(to bottom, #4CAF50, #45a049);
+    -fx-text-fill: white;
+    -fx-font-weight: bold;
+    -fx-padding: 5 15 5 15;
+    -fx-border-radius: 4;
+    -fx-background-radius: 4;
+    -fx-cursor: hand;
+}
+
+.action-button:hover {
+    -fx-background-color: linear-gradient(to bottom, #45a049, #3d8b40);
+    -fx-effect: dropshadow(gaussian, rgba(0,0,0,0.3), 4, 0, 0, 1);
+}
+
+.action-button:pressed {
+    -fx-background-color: #3d8b40;
+    -fx-effect: innershadow(gaussian, rgba(0,0,0,0.3), 4, 0, 0, 1);
+}
+
+.action-button:disabled {
+    -fx-opacity: 0.5;
+    -fx-cursor: default;
+}
+
+/* ============================================================================
+   TABLE VIEW
+   ============================================================================ */
+.table-view {
+    -fx-background-color: transparent;
+    -fx-table-cell-border-color: transparent;
+}
+
+.table-view .column-header {
+    -fx-background-color: linear-gradient(to bottom, #e0e0e0, #d0d0d0);
+    -fx-font-weight: bold;
+    -fx-padding: 5;
+}
+
+.table-view .column-header-background {
+    -fx-background-color: #e0e0e0;
+}
+
+.table-row-cell {
+    -fx-border-color: transparent;
+    -fx-border-width: 0;
+}
+
+.table-row-cell:selected {
+    -fx-background-color: #e3f2fd;
+    -fx-table-cell-border-color: #2196F3;
+}
+
+.table-row-cell:hover {
+    -fx-background-color: #f5f5f5;
+}
+
+.table-row-cell:selected:hover {
+    -fx-background-color: #bbdefb;
+}
+
+/* Checkbox column styling */
+.check-box-table-cell .check-box {
+    -fx-cursor: hand;
+}
+
+/* ============================================================================
+   TREE VIEW
+   ============================================================================ */
+.tree-view {
+    -fx-background-color: white;
+    -fx-border-color: #d0d0d0;
+    -fx-border-width: 1;
+}
+
+.tree-cell {
+    -fx-padding: 2 5 2 5;
+}
+
+.tree-cell:selected {
+    -fx-background-color: #2196F3;
+    -fx-text-fill: white;
+}
+
+.tree-cell:hover {
+    -fx-background-color: #e3f2fd;
+}
+
+/* ============================================================================
+   BUTTONS
+   ============================================================================ */
+.button {
+    -fx-background-color: linear-gradient(to bottom, #f0f0f0, #d0d0d0);
+    -fx-border-color: #a0a0a0;
+    -fx-border-width: 1;
+    -fx-border-radius: 3;
+    -fx-background-radius: 3;
+    -fx-padding: 5 15 5 15;
+    -fx-cursor: hand;
+}
+
+.button:hover {
+    -fx-background-color: linear-gradient(to bottom, #e0e0e0, #c0c0c0);
+    -fx-border-color: #808080;
+}
+
+.button:pressed {
+    -fx-background-color: #c0c0c0;
+}
+
+.button:disabled {
+    -fx-opacity: 0.6;
+    -fx-cursor: default;
+}
+
+/* Primary button style */
+.button-primary {
+    -fx-background-color: linear-gradient(to bottom, #2196F3, #1976D2);
+    -fx-text-fill: white;
+    -fx-font-weight: bold;
+}
+
+.button-primary:hover {
+    -fx-background-color: linear-gradient(to bottom, #1976D2, #1565C0);
+}
+
+/* Danger button style */
+.button-danger {
+    -fx-background-color: linear-gradient(to bottom, #f44336, #d32f2f);
+    -fx-text-fill: white;
+}
+
+.button-danger:hover {
+    -fx-background-color: linear-gradient(to bottom, #d32f2f, #c62828);
+}
+
+/* Success button style */
+.button-success {
+    -fx-background-color: linear-gradient(to bottom, #4CAF50, #388E3C);
+    -fx-text-fill: white;
+}
+
+.button-success:hover {
+    -fx-background-color: linear-gradient(to bottom, #388E3C, #2E7D32);
+}
+
+/* ============================================================================
+   TEXT FIELDS & AREAS
+   ============================================================================ */
+.text-field, .text-area {
+    -fx-background-color: white;
+    -fx-border-color: #c0c0c0;
+    -fx-border-width: 1;
+    -fx-border-radius: 3;
+    -fx-background-radius: 3;
+    -fx-padding: 5;
+}
+
+.text-field:focused, .text-area:focused {
+    -fx-border-color: #2196F3;
+    -fx-border-width: 2;
+}
+
+.text-area {
+    -fx-font-family: "Consolas", "Monaco", "Courier New", monospace;
+    -fx-font-size: 12px;
+}
+
+/* ============================================================================
+   DIALOGS
+   ============================================================================ */
+.dialog-pane {
+    -fx-background-color: white;
+    -fx-padding: 10;
+}
+
+.dialog-pane .header-panel {
+    -fx-background-color: linear-gradient(to bottom, #e0e0e0, #d0d0d0);
+    -fx-padding: 10;
+}
+
+.dialog-pane .content {
+    -fx-padding: 20;
+}
+
+.dialog-pane .button-bar .button {
+    -fx-min-width: 80;
+}
+
+/* ============================================================================
+   COMBO BOX
+   ============================================================================ */
+.combo-box {
+    -fx-background-color: white;
+    -fx-border-color: #c0c0c0;
+    -fx-border-width: 1;
+    -fx-border-radius: 3;
+    -fx-background-radius: 3;
+}
+
+.combo-box:focused {
+    -fx-border-color: #2196F3;
+    -fx-border-width: 2;
+}
+
+.combo-box-popup .list-view {
+    -fx-background-color: white;
+    -fx-border-color: #2196F3;
+    -fx-border-width: 1;
+}
+
+.combo-box-popup .list-cell {
+    -fx-padding: 5;
+}
+
+.combo-box-popup .list-cell:hover {
+    -fx-background-color: #e3f2fd;
+}
+
+/* ============================================================================
+   LIST VIEW
+   ============================================================================ */
+.list-view {
+    -fx-background-color: white;
+    -fx-border-color: #d0d0d0;
+    -fx-border-width: 1;
+}
+
+.list-cell {
+    -fx-padding: 5;
+}
+
+.list-cell:selected {
+    -fx-background-color: #2196F3;
+    -fx-text-fill: white;
+}
+
+.list-cell:hover {
+    -fx-background-color: #e3f2fd;
+}
+
+/* ============================================================================
+   CHECK BOX
+   ============================================================================ */
+.check-box {
+    -fx-cursor: hand;
+}
+
+.check-box:selected .box {
+    -fx-background-color: #2196F3;
+    -fx-border-color: #1976D2;
+}
+
+/* ============================================================================
+   LABELS
+   ============================================================================ */
+.label {
+    -fx-text-fill: #333333;
+}
+
+.label-header {
+    -fx-font-size: 16px;
+    -fx-font-weight: bold;
+    -fx-text-fill: #1976D2;
+}
+
+.label-error {
+    -fx-text-fill: #d32f2f;
+    -fx-font-weight: bold;
+}
+
+.label-success {
+    -fx-text-fill: #388E3C;
+    -fx-font-weight: bold;
+}
+
+.label-warning {
+    -fx-text-fill: #F57C00;
+    -fx-font-weight: bold;
+}
+
+/* ============================================================================
+   PROGRESS INDICATOR
+   ============================================================================ */
+.progress-indicator {
+    -fx-progress-color: #2196F3;
+}
+
+/* ============================================================================
+   SEPARATOR
+   ============================================================================ */
+.separator {
+    -fx-background-color: #d0d0d0;
+}
+
+/* ============================================================================
+   SCROLL BAR
+   ============================================================================ */
+.scroll-bar {
+    -fx-background-color: transparent;
+}
+
+.scroll-bar .thumb {
+    -fx-background-color: #c0c0c0;
+    -fx-background-radius: 5;
+}
+
+.scroll-bar .thumb:hover {
+    -fx-background-color: #a0a0a0;
+}
+
+.scroll-bar .increment-button,
+.scroll-bar .decrement-button {
+    -fx-background-color: transparent;
+}
+
+/* ============================================================================
+   CUSTOM CLASSES
+   ============================================================================ */
+
+/* Action list item in dialog */
+.action-list-item {
+    -fx-padding: 5;
+    -fx-border-color: #e0e0e0;
+    -fx-border-width: 0 0 1 0;
+}
+
+.action-list-item:hover {
+    -fx-background-color: #f5f5f5;
+}
+
+/* Script editor */
+.script-editor {
+    -fx-font-family: "Consolas", "Monaco", "Courier New", monospace;
+    -fx-font-size: 12px;
+    -fx-background-color: #f8f8f8;
+    -fx-border-color: #2196F3;
+    -fx-border-width: 2;
+    -fx-padding: 10;
+}
+
+/* Status indicator */
+.status-connected {
+    -fx-background-color: #4CAF50;
+    -fx-background-radius: 50%;
+    -fx-min-width: 12;
+    -fx-min-height: 12;
+    -fx-max-width: 12;
+    -fx-max-height: 12;
+}
+
+.status-disconnected {
+    -fx-background-color: #f44336;
+    -fx-background-radius: 50%;
+    -fx-min-width: 12;
+    -fx-min-height: 12;
+    -fx-max-width: 12;
+    -fx-max-height: 12;
+}
+
+/* Tooltip */
+.tooltip {
+    -fx-background-color: #333333;
+    -fx-text-fill: white;
+    -fx-padding: 5 10 5 10;
+    -fx-background-radius: 4;
+    -fx-font-size: 12px;
+}
+
+/* Badge for action count */
+.badge {
+    -fx-background-color: #2196F3;
+    -fx-text-fill: white;
+    -fx-background-radius: 10;
+    -fx-padding: 2 6 2 6;
+    -fx-font-size: 10px;
+    -fx-font-weight: bold;
+}
+
+/* Grid pane for forms */
+.form-grid {
+    -fx-hgap: 10;
+    -fx-vgap: 10;
+    -fx-padding: 10;
+}
+
+/* ============================================================================
+   RESPONSIVE MAIN WINDOW
+   ============================================================================ */
+.top-bar {
+    -fx-background-color: linear-gradient(to bottom, #ffffff, #eef3f9);
+    -fx-border-color: #d0d7de;
+    -fx-border-width: 0 0 1 0;
+}
+
+.app-title {
+    -fx-font-size: 18px;
+    -fx-font-weight: bold;
+    -fx-text-fill: #17456b;
+}
+
+.script-bar {
+    -fx-padding: 4 0 0 0;
+}
+
+.split-pane {
+    -fx-background-color: #f7f9fb;
+}
+
+.split-pane-divider {
+    -fx-background-color: #d0d7de;
+    -fx-padding: 0 1 0 1;
+}
+
+.table-view {
+    -fx-column-resize-policy: constrained-resize;
+}
+
+/* JavaScript editor (RichTextFX) */
+.js-editor-pane {
+    -fx-border-color: #d0d7de;
+    -fx-border-radius: 8;
+    -fx-background-radius: 8;
+    -fx-background-color: #ffffff;
+}
+.js-editor-header {
+    -fx-padding: 6 8 6 8;
+    -fx-background-color: #f6f8fa;
+    -fx-border-color: transparent transparent #d0d7de transparent;
+}
+.js-code-area {
+    -fx-font-family: "Cascadia Code", "JetBrains Mono", "Consolas", monospace;
+    -fx-font-size: 13px;
+    -fx-background-color: #ffffff;
+}
+.js-code-area .keyword { -fx-fill: #cf222e; -fx-font-weight: bold; }
+.js-code-area .string  { -fx-fill: #0a3069; }
+.js-code-area .comment { -fx-fill: #6e7781; -fx-font-style: italic; }
diff --git a/target/classes/styles/opcua-client-logo.png b/target/classes/styles/opcua-client-logo.png
new file mode 100644
index 0000000..3da1fd6
Binary files /dev/null and b/target/classes/styles/opcua-client-logo.png differ
diff --git a/target/classes/styles/opcua-client-logo.svg b/target/classes/styles/opcua-client-logo.svg
new file mode 100644
index 0000000..999be1a
--- /dev/null
+++ b/target/classes/styles/opcua-client-logo.svg
@@ -0,0 +1,27 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256">
+  <defs>
+    <linearGradient id="g" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0" stop-color="#007aff"/>
+      <stop offset="1" stop-color="#34c759"/>
+    </linearGradient>
+    <filter id="s" x="-20%" y="-20%" width="140%" height="140%">
+      <feDropShadow dx="0" dy="8" stdDeviation="10" flood-color="#0b2a42" flood-opacity="0.25"/>
+    </filter>
+  </defs>
+  <rect x="20" y="20" width="216" height="216" rx="50" fill="url(#g)" filter="url(#s)"/>
+  <circle cx="128" cy="128" r="72" fill="none" stroke="white" stroke-width="14" opacity="0.95"/>
+  <circle cx="128" cy="128" r="22" fill="white"/>
+  <g fill="white" opacity="0.95">
+    <circle cx="128" cy="45" r="12"/>
+    <circle cx="128" cy="211" r="12"/>
+    <circle cx="45" cy="128" r="12"/>
+    <circle cx="211" cy="128" r="12"/>
+  </g>
+  <g stroke="white" stroke-width="10" stroke-linecap="round" opacity="0.85">
+    <line x1="128" y1="57" x2="128" y2="90"/>
+    <line x1="128" y1="166" x2="128" y2="199"/>
+    <line x1="57" y1="128" x2="90" y2="128"/>
+    <line x1="166" y1="128" x2="199" y2="128"/>
+  </g>
+  <text x="128" y="238" text-anchor="middle" font-family="Segoe UI, Arial, sans-serif" font-size="28" font-weight="700" fill="white" opacity="0.95">OPC</text>
+</svg>
diff --git a/target/classes/styles/opcua-client.ico b/target/classes/styles/opcua-client.ico
new file mode 100644
index 0000000..a3b18c4
Binary files /dev/null and b/target/classes/styles/opcua-client.ico differ
diff --git a/target/classes/styles/opcua-simulator-icon.png b/target/classes/styles/opcua-simulator-icon.png
new file mode 100644
index 0000000..2a339b7
Binary files /dev/null and b/target/classes/styles/opcua-simulator-icon.png differ
diff --git a/target/classes/ui/config.fxml b/target/classes/ui/config.fxml
new file mode 100644
index 0000000..9359124
--- /dev/null
+++ b/target/classes/ui/config.fxml
@@ -0,0 +1,159 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.control.*?>
+<?import javafx.scene.layout.*?>
+
+<BorderPane xmlns="http://javafx.com/javafx/21" xmlns:fx="http://javafx.com/fxml/1"
+            fx:controller="de.opcua.app.ui.ConfigController"
+            prefWidth="980" prefHeight="760">
+  <top>
+    <Label text="Configuration" style="-fx-font-size:22px;-fx-font-weight:bold;" BorderPane.alignment="CENTER_LEFT">
+      <padding><Insets top="14" right="18" bottom="8" left="18"/></padding>
+    </Label>
+  </top>
+  <center>
+    <ScrollPane fitToWidth="true">
+      <VBox spacing="16">
+        <padding><Insets top="18" right="18" bottom="18" left="18"/></padding>
+        <TitledPane text="OPC UA Server" expanded="true">
+          <GridPane hgap="12" vgap="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <columnConstraints>
+              <ColumnConstraints minWidth="170" halignment="RIGHT"/>
+              <ColumnConstraints hgrow="ALWAYS"/>
+            </columnConstraints>
+            <Label text="Endpoint" GridPane.rowIndex="0" GridPane.columnIndex="0"/>
+            <TextField fx:id="endpointTextBox" GridPane.rowIndex="0" GridPane.columnIndex="1"/>
+            <Label text="Host" GridPane.rowIndex="1" GridPane.columnIndex="0"/>
+            <TextField fx:id="hostTextBox" GridPane.rowIndex="1" GridPane.columnIndex="1"/>
+          </GridPane>
+        </TitledPane>
+
+        <TitledPane text="HTTP / HTTPS" expanded="true">
+          <GridPane hgap="12" vgap="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <columnConstraints>
+              <ColumnConstraints minWidth="170" halignment="RIGHT"/>
+              <ColumnConstraints hgrow="ALWAYS"/>
+              <ColumnConstraints minWidth="110"/>
+            </columnConstraints>
+            <CheckBox fx:id="httpEnabledCheckBox" text="Enable HTTP" GridPane.rowIndex="0" GridPane.columnIndex="1"/>
+            <Label text="HTTP Port" GridPane.rowIndex="1" GridPane.columnIndex="0"/>
+            <TextField fx:id="httpPortTextBox" GridPane.rowIndex="1" GridPane.columnIndex="1" maxWidth="140"/>
+            <Label text="z. B. 8081" GridPane.rowIndex="1" GridPane.columnIndex="2" style="-fx-text-fill:#888;"/>
+
+            <CheckBox fx:id="httpsEnabledCheckBox" text="Enable HTTPS" GridPane.rowIndex="2" GridPane.columnIndex="1"/>
+            <Label text="HTTPS Port" GridPane.rowIndex="3" GridPane.columnIndex="0"/>
+            <TextField fx:id="httpsPortTextBox" GridPane.rowIndex="3" GridPane.columnIndex="1" maxWidth="140"/>
+            <Label text="z. B. 8443" GridPane.rowIndex="3" GridPane.columnIndex="2" style="-fx-text-fill:#888;"/>
+            <Label text="Keystore" GridPane.rowIndex="4" GridPane.columnIndex="0"/>
+            <HBox spacing="8" GridPane.rowIndex="4" GridPane.columnIndex="1" GridPane.columnSpan="2">
+              <TextField fx:id="keystorePathTextBox" HBox.hgrow="ALWAYS"/>
+              <Button text="Browse..." onAction="#BrowseKeystore_Click"/>
+            </HBox>
+            <Label text="Keystore Password" GridPane.rowIndex="5" GridPane.columnIndex="0"/>
+            <PasswordField fx:id="keystorePasswordTextBox" GridPane.rowIndex="5" GridPane.columnIndex="1"/>
+            <Label text="Keystore Type" GridPane.rowIndex="6" GridPane.columnIndex="0"/>
+            <ComboBox fx:id="keystoreTypeComboBox" GridPane.rowIndex="6" GridPane.columnIndex="1" maxWidth="160"/>
+          </GridPane>
+        </TitledPane>
+
+
+        <TitledPane text="Portable Config / Verschluesselung / REST Auth" expanded="true">
+          <GridPane hgap="12" vgap="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <columnConstraints>
+              <ColumnConstraints minWidth="190" halignment="RIGHT"/>
+              <ColumnConstraints hgrow="ALWAYS"/>
+            </columnConstraints>
+
+            <Label text="Config-Verzeichnis" GridPane.rowIndex="0" GridPane.columnIndex="0"/>
+            <Label fx:id="configDirectoryLabel" GridPane.rowIndex="0" GridPane.columnIndex="1" style="-fx-text-fill:#666;-fx-font-family:monospace;" wrapText="true"/>
+
+            <Label text="Settings-Datei" GridPane.rowIndex="1" GridPane.columnIndex="0"/>
+            <Label fx:id="settingsPathLabel" GridPane.rowIndex="1" GridPane.columnIndex="1" style="-fx-text-fill:#666;-fx-font-family:monospace;" wrapText="true"/>
+
+            <CheckBox fx:id="configEncryptionEnabledCheckBox" text="Config-Dateien verschluesseln (Actions, Templates, System Init)" GridPane.rowIndex="2" GridPane.columnIndex="1"/>
+            <Label text="Config-Passwort" GridPane.rowIndex="3" GridPane.columnIndex="0"/>
+            <PasswordField fx:id="configEncryptionPasswordField" GridPane.rowIndex="3" GridPane.columnIndex="1" promptText="Passwort fuer AES-GCM Verschluesselung"/>
+
+            <CheckBox fx:id="restAuthEnabledCheckBox" text="REST-API Authentifizierung aktivieren" GridPane.rowIndex="4" GridPane.columnIndex="1"/>
+            <Label text="REST Benutzer" GridPane.rowIndex="5" GridPane.columnIndex="0"/>
+            <TextField fx:id="restAuthUserTextBox" GridPane.rowIndex="5" GridPane.columnIndex="1" promptText="admin"/>
+            <Label text="REST Passwort" GridPane.rowIndex="6" GridPane.columnIndex="0"/>
+            <PasswordField fx:id="restAuthPasswordField" GridPane.rowIndex="6" GridPane.columnIndex="1" promptText="Leer lassen = bestehendes Passwort behalten"/>
+
+            <Label text="Hinweis" GridPane.rowIndex="7" GridPane.columnIndex="0"/>
+            <Label text="Nach Aktivierung der REST-Authentifizierung muessen REST-Clients Basic Auth verwenden. Die Web-Oberflaeche fragt das Passwort automatisch ab." GridPane.rowIndex="7" GridPane.columnIndex="1" wrapText="true" style="-fx-text-fill:#666;"/>
+          </GridPane>
+        </TitledPane>
+
+        <TitledPane text="System Init / RegLogin" expanded="true">
+          <VBox spacing="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <Label text="Dieses globale Initial-Script wird dauerhaft gespeichert und beim Start/Connect geladen. Im Service-Modus laeuft es nach erfolgreichem OPC-Connect/Reconnect, wenn 'Nach OPC Connect' aktiv ist." wrapText="true"/>
+            <Label fx:id="systemInitPathLabel" style="-fx-text-fill:#666;-fx-font-family:monospace;"/>
+            <HBox spacing="18">
+              <CheckBox fx:id="systemInitEnabledCheckBox" text="Aktiv"/>
+              <CheckBox fx:id="systemInitRunAtProgramStartCheckBox" text="Bei Programmstart"/>
+              <CheckBox fx:id="systemInitRunAfterConnectCheckBox" text="Nach OPC Connect/Reconnect" selected="true"/>
+            </HBox>
+            <HBox spacing="8">
+              <Button text="RegLogin Template einfuegen" onAction="#InsertRegLoginTemplate_Click"/>
+              <Button text="Speichern &amp; jetzt ausfuehren" onAction="#RunSystemInit_Click"/>
+            </HBox>
+            <StackPane fx:id="systemInitEditorHost" minHeight="280" VBox.vgrow="ALWAYS"/>
+          </VBox>
+        </TitledPane>
+
+        <TitledPane text="Script Templates / Button-Vorlagen" expanded="false">
+          <VBox spacing="10">
+            <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+            <Label text="Hier werden GET/POST/SET und eigene Templates gepflegt. Fuer jedes aktivierte Template erscheint im Create-New-Action-Dialog automatisch ein Button. Platzhalter werden beim Einfuegen durch feste NodeId-Codezeilen ersetzt." wrapText="true"/>
+            <Label fx:id="templatePathLabel" style="-fx-text-fill:#666;-fx-font-family:monospace;"/>
+            <SplitPane dividerPositions="0.30" minHeight="360" VBox.vgrow="ALWAYS">
+              <items>
+                <VBox spacing="8">
+                  <ListView fx:id="templateListView" minWidth="220" VBox.vgrow="ALWAYS"/>
+                  <HBox spacing="8">
+                    <Button text="Neu" onAction="#NewTemplate_Click"/>
+                    <Button text="Loeschen" onAction="#DeleteTemplate_Click"/>
+                  </HBox>
+                </VBox>
+                <VBox spacing="8">
+                  <GridPane hgap="10" vgap="8">
+                    <columnConstraints>
+                      <ColumnConstraints minWidth="90" halignment="RIGHT"/>
+                      <ColumnConstraints hgrow="ALWAYS"/>
+                    </columnConstraints>
+                    <Label text="Name" GridPane.rowIndex="0" GridPane.columnIndex="0"/>
+                    <TextField fx:id="templateNameField" GridPane.rowIndex="0" GridPane.columnIndex="1" promptText="z. B. POST an MES"/>
+                    <Label text="Status" GridPane.rowIndex="1" GridPane.columnIndex="0"/>
+                    <CheckBox fx:id="templateEnabledCheckBox" text="Aktiv / Button anzeigen" selected="true" GridPane.rowIndex="1" GridPane.columnIndex="1"/>
+                  </GridPane>
+                  <HBox spacing="8">
+                    <Button text="Platzhalter einfuegen" onAction="#InsertTemplatePlaceholders_Click"/>
+                    <Button text="Templates speichern" onAction="#SaveTemplates_Click"/>
+                    <Button text="Standard GET/POST/SET wiederherstellen" onAction="#ResetTemplates_Click"/>
+                  </HBox>
+                  <Label text="JavaScript Template" style="-fx-font-weight:bold;"/>
+                  <StackPane fx:id="templateEditorHost" minHeight="260" VBox.vgrow="ALWAYS"/>
+                  <Label text="Platzhalter: {{readNumberVars}}, {{readTextVars}}, {{payloadFields}}, {{opcWritesFromResult}}, {{selectedNodesComment}}, {{firstNodeIdJs}}, {{firstAlias}}" wrapText="true" style="-fx-text-fill:#666;"/>
+                </VBox>
+              </items>
+            </SplitPane>
+          </VBox>
+        </TitledPane>
+
+      </VBox>
+    </ScrollPane>
+  </center>
+  <bottom>
+    <HBox spacing="10" alignment="CENTER_RIGHT">
+      <padding><Insets top="14" right="14" bottom="14" left="14"/></padding>
+      <Button text="Save" prefWidth="110" onAction="#SaveButton_Click" style="-fx-background-color:#007aff;-fx-text-fill:white;-fx-font-weight:bold;"/>
+      <Button text="Cancel" prefWidth="110" onAction="#CancelButton_Click" style="-fx-background-color:#8e8e93;-fx-text-fill:white;"/>
+    </HBox>
+  </bottom>
+</BorderPane>
diff --git a/target/classes/ui/main.fxml b/target/classes/ui/main.fxml
new file mode 100644
index 0000000..a04a82a
--- /dev/null
+++ b/target/classes/ui/main.fxml
@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.control.*?>
+<?import javafx.scene.image.Image?>
+<?import javafx.scene.image.ImageView?>
+<?import javafx.scene.layout.*?>
+
+<BorderPane xmlns:fx="http://javafx.com/fxml"
+            fx:controller="de.opcua.app.ui.MainController"
+            prefWidth="1262" prefHeight="619"
+            minWidth="900" minHeight="520"
+            stylesheets="@../styles/application.css">
+
+  <top>
+    <HBox spacing="8" alignment="CENTER_LEFT" styleClass="top-bar">
+      <padding>
+        <Insets top="10" right="12" bottom="10" left="12"/>
+      </padding>
+      <ImageView fitWidth="28" fitHeight="28" preserveRatio="true" smooth="true">
+        <image>
+          <Image url="@../styles/opcua-client-logo.png"/>
+        </image>
+      </ImageView>
+      <Label text="OPC UA Client" styleClass="app-title"/>
+      <Region HBox.hgrow="ALWAYS"/>
+      <Button fx:id="connectButton" text="Connect" minWidth="92" onAction="#connectButton_Click" styleClass="button-primary"/>
+      <Button fx:id="saveButton" text="Save" minWidth="80" onAction="#onSave"/>
+      <Button fx:id="settingsButton" text="Settings" minWidth="92" onAction="#onSettings"/>
+    </HBox>
+  </top>
+
+  <center>
+    <SplitPane dividerPositions="0.25" BorderPane.alignment="CENTER">
+      <items>
+        <VBox spacing="8" minWidth="240">
+          <padding>
+            <Insets top="10" right="6" bottom="10" left="10"/>
+          </padding>
+          <Label text="OPC UA Tree" styleClass="label-header"/>
+          <TreeView fx:id="myTreeView" VBox.vgrow="ALWAYS" minWidth="220"
+                    onMouseClicked="#myTreeView_AfterSelect"/>
+        </VBox>
+
+        <VBox spacing="8" minWidth="520">
+          <padding>
+            <Insets top="10" right="10" bottom="10" left="6"/>
+          </padding>
+          <TableView fx:id="nodeListview" VBox.vgrow="ALWAYS" minHeight="260">
+            <columns>
+              <TableColumn fx:id="checkBoxColumn" text="Select" prefWidth="70"/>
+              <TableColumn fx:id="colDisplayName" text="DisplayName" prefWidth="160"/>
+              <TableColumn fx:id="colNodeType" text="NodeType" prefWidth="110"/>
+              <TableColumn fx:id="colNodeId" text="NodeId" prefWidth="280"/>
+              <TableColumn fx:id="colNamespaceIndex" text="NamespaceIndex" prefWidth="120"/>
+              <TableColumn fx:id="colIdentifierType" text="IdentifierType" prefWidth="120"/>
+              <TableColumn fx:id="colValue" text="Value" prefWidth="150"/>
+            </columns>
+            <columnResizePolicy>
+              <TableView fx:constant="CONSTRAINED_RESIZE_POLICY"/>
+            </columnResizePolicy>
+          </TableView>
+
+          <HBox spacing="8" alignment="CENTER_LEFT" styleClass="script-bar">
+            <Label text="JS:"/>
+            <TextField fx:id="scriptField" HBox.hgrow="ALWAYS" promptText="opc.read(&quot;ns=...&quot;)"/>
+            <Button fx:id="runScriptButton" text="Run" minWidth="70" onAction="#runScript"/>
+          </HBox>
+
+          <TextArea fx:id="logArea" visible="false" managed="false" prefRowCount="0"/>
+        </VBox>
+      </items>
+    </SplitPane>
+  </center>
+</BorderPane>
diff --git a/target/classes/web/web-interface.html b/target/classes/web/web-interface.html
new file mode 100644
index 0000000..54ceed0
--- /dev/null
+++ b/target/classes/web/web-interface.html
@@ -0,0 +1,1217 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
+    <meta name="mobile-web-app-capable" content="yes">
+    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
+    <meta name="theme-color" content="#007aff" media="(prefers-color-scheme: light)">
+    <meta name="theme-color" content="#0a0a0a" media="(prefers-color-scheme: dark)">
+    <title>OPC UA Control</title>
+    <link rel="icon" href="/favicon.ico">
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.16/codemirror.min.css">
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.16/theme/material-darker.min.css">
+    <style>
+        :root {
+            --bg-primary: #f2f2f7;
+            --bg-secondary: #ffffff;
+            --bg-tertiary: #f2f2f7;
+            --text-primary: #1c1c1e;
+            --text-secondary: #8e8e93;
+            --border-color: rgba(60,60,67,0.18);
+            --blue: #007aff;
+            --green: #34c759;
+            --red: #ff3b30;
+            --orange: #ff9500;
+            --shadow: 0 1px 3px rgba(0,0,0,0.08);
+        }
+        @media (prefers-color-scheme: dark) {
+            :root {
+                --bg-primary: #000000;
+                --bg-secondary: #1c1c1e;
+                --bg-tertiary: #2c2c2e;
+                --text-primary: #ffffff;
+                --text-secondary: #98989d;
+                --border-color: rgba(84,84,88,0.48);
+                --shadow: 0 1px 3px rgba(0,0,0,0.3);
+            }
+        }
+        * { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
+        body { font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', Arial, sans-serif; background: var(--bg-primary); color: var(--text-primary); }
+        .header { background: var(--blue); color: white; padding: max(env(safe-area-inset-top), 20px) 20px 20px 20px; box-shadow: 0 2px 10px rgba(0,0,0,0.2); position: sticky; top: 0; z-index: 100; }
+        .header h1 { font-size: clamp(20px, 5vw, 28px); font-weight: 700; margin-bottom: 8px; display:flex; align-items:center; gap:10px; }
+        .app-logo { width: 36px; height: 36px; border-radius: 10px; box-shadow: 0 2px 8px rgba(0,0,0,0.20); flex-shrink: 0; }
+        .status-badge { display: inline-flex; align-items: center; gap: 6px; background: rgba(255,255,255,0.2); padding: 6px 12px; border-radius: 20px; font-size: 13px; font-weight: 600; }
+        .status-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--red); }
+        .status-dot.connected { background: var(--green); animation: pulse 2s infinite; }
+        @keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.6; } }
+        .toolbar { background: var(--bg-secondary); padding: 12px 20px; border-bottom: 0.5px solid var(--border-color); display: flex; gap: 8px; overflow-x: auto; -webkit-overflow-scrolling: touch; align-items: center; }
+        .toolbar::-webkit-scrollbar { display: none; }
+        .btn { background: var(--blue); color: white; border: none; padding: 10px 16px; border-radius: 10px; font-size: 15px; font-weight: 600; cursor: pointer; transition: all 0.2s; white-space: nowrap; touch-action: manipulation; }
+        .btn:active { transform: scale(0.96); }
+        .btn-success { background: var(--green); }
+        .btn-danger { background: var(--red); }
+        .btn-secondary { background: var(--text-secondary); }
+        .btn-small { padding: 6px 12px; font-size: 13px; border-radius: 8px; }
+        .btn:disabled { opacity: 0.5; cursor: not-allowed; }
+        .twin-status { font-size: 12px; color: var(--text-secondary); white-space: nowrap; }
+        .container { max-width: 1600px; margin: 0 auto; padding: clamp(12px, 2vw, 20px); padding-bottom: max(env(safe-area-inset-bottom), 16px); }
+        .grid { display: grid; grid-template-columns: 1fr; gap: 16px; }
+        @media (min-width: 768px) { .grid { grid-template-columns: 350px 1fr; } }
+        @media (min-width: 1024px) { .grid { grid-template-columns: 400px 1fr; } }
+        .card { background: var(--bg-secondary); border-radius: 12px; margin-bottom: 16px; box-shadow: var(--shadow); overflow: hidden; }
+        .card-header { padding: 16px; border-bottom: 0.5px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
+        .card-title { font-size: 17px; font-weight: 600; }
+        .tree-container { max-height: 70vh; overflow-y: auto; -webkit-overflow-scrolling: touch; }
+        @media (min-width: 768px) { .tree-container { max-height: 600px; } }
+        .tree-node { padding: 10px 16px; border-bottom: 0.5px solid var(--border-color); cursor: pointer; user-select: none; }
+        .tree-node:active { background: var(--bg-tertiary); }
+        .tree-node-content { display: flex; align-items: center; gap: 8px; }
+        .tree-expand { width: 24px; height: 24px; border-radius: 50%; background: var(--bg-tertiary); display: flex; align-items: center; justify-content: center; font-size: 14px; transition: transform 0.2s; flex-shrink: 0; cursor: pointer; }
+        .tree-expand.expanded { transform: rotate(90deg); }
+        .tree-expand.loading-spin { animation: spin 0.7s linear infinite; }
+        .tree-children { padding-left: 28px; display: none; }
+        .tree-children.show { display: block; }
+        .value-badge { margin-left: 8px; padding: 2px 8px; background: var(--blue); color: white; border-radius: 6px; font-size: 11px; font-weight: 600; font-family: 'SF Mono', Monaco, monospace; }
+        .table-container { overflow-x: auto; -webkit-overflow-scrolling: touch; }
+        table { width: 100%; border-collapse: collapse; font-size: clamp(13px, 2vw, 15px); }
+        thead { background: var(--bg-tertiary); position: sticky; top: 0; z-index: 1; }
+        th { padding: 12px 8px; text-align: left; font-weight: 600; font-size: 13px; color: var(--text-secondary); text-transform: uppercase; border-bottom: 0.5px solid var(--border-color); white-space: nowrap; }
+        td { padding: 12px 8px; border-bottom: 0.5px solid var(--border-color); }
+        .value-cell { font-family: 'SF Mono', Monaco, 'Courier New', monospace; font-size: 14px; font-weight: 500; background: var(--bg-tertiary); padding: 6px 10px; border-radius: 6px; display: inline-block; cursor: pointer; transition: background 0.3s; }
+        .value-cell.updating { animation: highlight 0.5s; }
+        @keyframes highlight { 0%, 100% { background: var(--bg-tertiary); } 50% { background: var(--orange); } }
+        .modal { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.5); z-index: 1000; }
+        .modal.active { display: flex; align-items: flex-end; justify-content: center; }
+        @media (min-width: 768px) { .modal.active { align-items: center; } }
+        .modal-content { background: var(--bg-secondary); border-radius: 12px 12px 0 0; padding: 24px; max-width: 600px; width: 100%; max-height: 85vh; overflow-y: auto; }
+        .modal-content.configuration-content { max-width: 980px; }
+        @media (min-width: 768px) { .modal-content { border-radius: 12px; } }
+        .modal-header { font-size: 20px; font-weight: 700; margin-bottom: 20px; }
+        .configuration-content .modal-header { font-size: 22px; margin-bottom: 14px; }
+        .config-pane { border: 1px solid var(--border-color); border-radius: 12px; margin-bottom: 16px; background: var(--bg-secondary); overflow: hidden; }
+        .config-pane-title { padding: 12px 14px; font-weight: 700; border-bottom: 1px solid var(--border-color); background: var(--bg-tertiary); }
+        .config-pane-body { padding: 14px; }
+        .config-checkbox-row { display:flex; gap:18px; flex-wrap:wrap; align-items:center; margin: 10px 0 12px 0; }
+        .config-path { font-size:12px; color:var(--text-secondary); font-family:'SF Mono', Monaco, monospace; margin: 8px 0 10px 0; word-break: break-all; }
+        .config-actions { display:flex; gap:8px; flex-wrap:wrap; margin-bottom:10px; }
+        .configuration-content .CodeMirror { min-height: 280px; }
+        .form-group { margin-bottom: 16px; }
+        .form-label { display: block; margin-bottom: 8px; font-size: 13px; font-weight: 600; color: var(--text-secondary); text-transform: uppercase; }
+        .form-input, .form-select, .form-textarea { width: 100%; padding: 12px; border: 0.5px solid var(--border-color); border-radius: 10px; font-size: 16px; background: var(--bg-tertiary); color: var(--text-primary); transition: all 0.2s; }
+        .form-input:focus, .form-select:focus, .form-textarea:focus { outline: none; border-color: var(--blue); box-shadow: 0 0 0 4px rgba(0,122,255,0.1); }
+        .form-textarea { min-height: 120px; font-family: 'SF Mono', Monaco, monospace; resize: vertical; }
+        .badge { display: inline-block; padding: 4px 8px; background: var(--blue); color: white; border-radius: 6px; font-size: 12px; font-weight: 600; }
+        .badge-success { background: var(--green); }
+        .badge-warning { background: var(--orange); }
+        .btn-delete { background: none; border: none; color: var(--red); font-size: 20px; cursor: pointer; padding: 4px 8px; border-radius: 6px; }
+        .empty-state { text-align: center; padding: 40px 20px; color: var(--text-secondary); }
+        .empty-icon { font-size: 48px; margin-bottom: 12px; }
+        .spinner { width: 16px; height: 16px; border: 2px solid var(--bg-tertiary); border-top: 2px solid var(--blue); border-radius: 50%; animation: spin 0.8s linear infinite; display: inline-block; vertical-align: middle; }
+        @keyframes spin { to { transform: rotate(360deg); } }
+        .list-item { padding: 12px 16px; border-bottom: 0.5px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
+        .list-item:last-child { border-bottom: none; }
+        .code-helper { border: 1px solid var(--border-color); background: var(--bg-tertiary); border-radius: 10px; padding: 10px; margin-bottom: 12px; }
+        .code-helper-list { max-height: 180px; overflow: auto; border: 1px solid var(--border-color); border-radius: 8px; padding: 8px; background: var(--bg-secondary); margin: 8px 0; }
+        .code-helper-row { display: grid; grid-template-columns: 24px minmax(120px, 1fr) minmax(140px, 1.3fr); gap: 8px; align-items: center; padding: 6px 0; border-bottom: 1px solid var(--border-color); }
+        .code-helper-row:last-child { border-bottom: none; }
+        .code-helper-alias { width: 100%; padding: 6px 8px; border: 1px solid var(--border-color); border-radius: 8px; background: var(--bg-tertiary); color: var(--text-primary); }
+        .CodeMirror { min-height: 220px; border-radius: 10px; font-size: 14px; font-family: 'SF Mono', Monaco, monospace; }
+        .template-manager-grid { display:grid; grid-template-columns:minmax(180px,0.8fr) minmax(260px,1.6fr); gap:12px; }
+        .template-list { min-height:220px; border:1px solid var(--border-color); border-radius:10px; background:var(--bg-secondary); overflow:auto; }
+        .template-list-item { padding:10px 12px; border-bottom:1px solid var(--border-color); cursor:pointer; display:flex; justify-content:space-between; gap:8px; }
+        .template-list-item.active { background:rgba(0,122,255,0.16); }
+        @media(max-width:800px){ .template-manager-grid { grid-template-columns:1fr; } }
+    </style>
+</head>
+<body>
+    <div class="header">
+        <h1><img src="/assets/opcua-client-logo.svg" class="app-logo" alt=""> OPC UA Control</h1>
+        <div class="status-badge">
+            <div class="status-dot" id="statusDot"></div>
+            <span id="statusText">Disconnected</span>
+        </div>
+    </div>
+
+    <div class="toolbar">
+        <button class="btn btn-success" onclick="loadRoot()" id="loadTreeBtn">🌳 Load Tree</button>
+        <button class="btn" onclick="exportTwin()">⬇ Export JSON</button>
+        <button class="btn" onclick="openConfigurationModal()">⚙ Configuration</button>
+        <button class="btn btn-secondary" onclick="window.location.href='/help'">📘 Hilfe / REST API</button>
+        <button class="btn btn-secondary" onclick="window.location.href='/api/openapi.json'">🧭 OpenAPI</button>
+        <button class="btn" onclick="toggleAutoRefresh()"><span id="refreshLabel">▶ Live</span></button>
+        <span class="twin-status" id="twinStatus"></span>
+    </div>
+
+    <div class="container">
+        <div class="grid">
+            <!-- Tree -->
+            <div class="card">
+                <div class="card-header">
+                    <div class="card-title">OPC UA Tree</div>
+                    <div id="treeInfo" style="font-size:12px;color:var(--text-secondary)"></div>
+                </div>
+                <div class="tree-container">
+                    <div id="treeView">
+                        <div class="empty-state">
+                            <div class="empty-icon">🌳</div>
+                            <div>Click "Load Tree"</div>
+                        </div>
+                    </div>
+                </div>
+            </div>
+
+            <!-- Right column -->
+            <div>
+                <div class="card">
+                    <div class="card-header">
+                        <div class="card-title">Monitored Nodes</div>
+                        <span class="badge" id="nodeCount">0</span>
+                    </div>
+                    <div class="table-container">
+                        <table>
+                            <thead>
+                                <tr>
+                                    <th>Name</th>
+                                    <th>NodeID</th>
+                                    <th>NS</th>
+                                    <th>Type</th>
+                                    <th>Value</th>
+                                    <th>Actions</th>
+                                    <th></th>
+                                </tr>
+                            </thead>
+                            <tbody id="nodesTableBody">
+                                <tr><td colspan="7"><div class="empty-state"><div class="empty-icon">📊</div><div>No nodes</div></div></td></tr>
+                            </tbody>
+                        </table>
+                    </div>
+                </div>
+
+                <div class="card">
+                    <div class="card-header">
+                        <div class="card-title">Actions</div>
+                        <span class="badge badge-success" id="actionCount">0</span>
+                    </div>
+                    <div id="actionsList">
+                        <div class="empty-state"><div class="empty-icon">⚡</div><div>No actions</div></div>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+
+
+    <!-- Configuration Modal -->
+    <div class="modal" id="systemInitModal">
+        <div class="modal-content configuration-content">
+            <div class="modal-header">Configuration</div>
+
+            <div class="config-pane">
+                <div class="config-pane-title">Portable Config / Verschlüsselung / REST Auth</div>
+                <div class="config-pane-body">
+                    <div style="font-size:13px;color:var(--text-secondary);line-height:1.45;margin-bottom:8px">
+                        Alle Definitionen werden im Unterordner <b>config</b> neben der Anwendung gespeichert. Optional können Actions, Templates und System Init verschlüsselt werden.
+                    </div>
+                    <div class="config-path" id="configDirectoryLabel">config</div>
+                    <div class="config-path" id="settingsFileLabel">config/settings.json</div>
+
+                    <div class="config-checkbox-row">
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="configEncryptionEnabled"> Config-Dateien verschlüsseln
+                        </label>
+                    </div>
+                    <div class="form-group">
+                        <label class="form-label">Config-Passwort</label>
+                        <input type="password" class="form-input" id="configEncryptionPassword" placeholder="Passwort für AES-GCM Verschlüsselung">
+                    </div>
+
+                    <div class="config-checkbox-row">
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="restAuthEnabled"> REST-API Authentifizierung aktivieren
+                        </label>
+                    </div>
+                    <div class="form-group">
+                        <label class="form-label">REST Benutzer</label>
+                        <input type="text" class="form-input" id="restAuthUser" placeholder="admin">
+                    </div>
+                    <div class="form-group">
+                        <label class="form-label">REST Passwort</label>
+                        <input type="password" class="form-input" id="restAuthPassword" placeholder="Leer lassen = bestehendes Passwort behalten">
+                    </div>
+                    <div id="securityInfo" style="font-size:12px;color:var(--text-secondary);margin-top:8px"></div>
+                </div>
+            </div>
+
+            <div class="config-pane">
+                <div class="config-pane-title">System Init / RegLogin</div>
+                <div class="config-pane-body">
+                    <div style="font-size:13px;color:var(--text-secondary);line-height:1.45;margin-bottom:8px">
+                        Dieses globale Initial-Script wird dauerhaft gespeichert und beim Start/Connect geladen.
+                        Im Service-Modus läuft es nach erfolgreichem OPC-Connect/Reconnect, wenn <b>Nach OPC Connect</b> aktiv ist.
+                    </div>
+                    <div class="config-path" id="systemInitPathLabel">config/system-init-script.json</div>
+
+                    <div class="config-checkbox-row">
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="systemInitEnabled"> Aktiv
+                        </label>
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="systemInitRunAtProgramStart"> Bei Programmstart
+                        </label>
+                        <label style="display:flex;gap:8px;align-items:center">
+                            <input type="checkbox" id="systemInitRunAfterConnect"> Nach OPC Connect/Reconnect
+                        </label>
+                    </div>
+
+                    <div class="config-actions">
+                        <button type="button" class="btn" onclick="insertRegLoginTemplate()">RegLogin Template einfügen</button>
+                        <button type="button" class="btn btn-success" onclick="saveSystemInit(true)">Speichern &amp; jetzt ausführen</button>
+                    </div>
+
+                    <label class="form-label">JavaScript</label>
+                    <textarea class="form-textarea js-editor" id="systemInitScript" placeholder="var response = http.postJson(&quot;http://localhost:9000/api/reglogin&quot;, { client: &quot;opcua-client&quot; });&#10;var result = JSON.parse(response.body);&#10;global.session = result;&#10;global.token = result.token;&#10;log.info(&quot;RegLogin OK&quot;);"></textarea>
+                    <div id="systemInitInfo" style="font-size:12px;color:var(--text-secondary);margin-top:10px"></div>
+                </div>
+            </div>
+
+            <div class="config-pane">
+                <div class="config-pane-title">Script Templates / Button-Vorlagen</div>
+                <div class="config-pane-body">
+                    <div style="font-size:13px;color:var(--text-secondary);line-height:1.45;margin-bottom:8px">
+                        GET, POST und SET sind nur Standard-Templates. Du kannst sie ändern, deaktivieren oder beliebig viele eigene Templates anlegen. Für jedes aktive Template wird im Dialog <b>Create New Action</b> automatisch ein Button erzeugt.
+                    </div>
+                    <div class="config-path" id="scriptTemplatePathLabel">config/script-templates.json</div>
+                    <div class="template-manager-grid">
+                        <div>
+                            <div id="scriptTemplateList" class="template-list"></div>
+                            <div style="display:flex;gap:6px;flex-wrap:wrap;margin-top:8px">
+                                <button type="button" class="btn btn-small" onclick="newScriptTemplate()">Neu</button>
+                                <button type="button" class="btn btn-small btn-secondary" onclick="deleteScriptTemplate()">Löschen</button>
+                                <button type="button" class="btn btn-small" onclick="resetScriptTemplates()">GET/POST/SET Reset</button>
+                            </div>
+                        </div>
+                        <div>
+                            <label class="form-label">Name / Button-Text</label>
+                            <input type="text" class="form-input" id="scriptTemplateName" placeholder="z. B. POST an MES">
+                            <label style="display:flex;gap:8px;align-items:center;margin:10px 0">
+                                <input type="checkbox" id="scriptTemplateEnabled" checked> Aktiv / Button anzeigen
+                            </label>
+                            <div style="display:flex;gap:6px;flex-wrap:wrap;margin-bottom:8px">
+                                <button type="button" class="btn btn-small" onclick="insertTemplatePlaceholders()">Platzhalter einfügen</button>
+                                <button type="button" class="btn btn-small btn-success" onclick="saveScriptTemplates()">Templates speichern</button>
+                            </div>
+                            <label class="form-label">JavaScript Template</label>
+                            <textarea class="form-textarea js-editor" id="scriptTemplateCode" placeholder="{{readNumberVars}}&#10;var response = http.postJson(&quot;http://localhost:9000/api/process&quot;, {&#10;{{payloadFields}}});&#10;var result = JSON.parse(response.body);&#10;global.apiResult = result;&#10;{{opcWritesFromResult}}"></textarea>
+                            <div style="font-size:12px;color:var(--text-secondary);margin-top:8px;line-height:1.45">
+                                Platzhalter: <code>{{readNumberVars}}</code>, <code>{{readTextVars}}</code>, <code>{{payloadFields}}</code>, <code>{{opcWritesFromResult}}</code>, <code>{{selectedNodesComment}}</code>, <code>{{firstNodeIdJs}}</code>, <code>{{firstAlias}}</code>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+            </div>
+
+            <div style="display:flex;gap:8px;justify-content:flex-end;flex-wrap:wrap">
+                <button class="btn" style="min-width:110px" onclick="saveConfiguration()">Save</button>
+                <button class="btn btn-secondary" style="min-width:110px" onclick="closeSystemInitModal()">Cancel</button>
+            </div>
+        </div>
+    </div>
+
+    <!-- Action Modal -->
+    <div class="modal" id="actionModal">
+        <div class="modal-content">
+            <div class="modal-header">Create Action</div>
+            <div class="form-group">
+                <label class="form-label">Name</label>
+                <input type="text" class="form-input" id="actionName" placeholder="Temperature Alert">
+            </div>
+            <div class="form-group">
+                <label class="form-label">Trigger Type</label>
+                <select class="form-select" id="triggerType" onchange="updateTriggerFields()">
+                    <option value="ON_CHANGE">On Change</option>
+                    <option value="ON_EVEN">On Even Number</option>
+                    <option value="ON_ODD">On Odd Number</option>
+                    <option value="ON_TRUE">On True</option>
+                    <option value="ON_FALSE">On False</option>
+                    <option value="ON_VALUE">On Specific Value</option>
+                    <option value="ON_GREATER_THAN">On Greater Than</option>
+                    <option value="ON_LESS_THAN">On Less Than</option>
+                    <option value="ON_INTERVAL">On Time Interval</option>
+                </select>
+            </div>
+            <div class="form-group" id="triggerValueGroup" style="display:none">
+                <label class="form-label">Trigger Value</label>
+                <input type="text" class="form-input" id="triggerValue" placeholder="e.g., 100">
+            </div>
+            <div class="form-group" id="intervalGroup" style="display:none">
+                <label class="form-label">Interval (ms)</label>
+                <input type="number" class="form-input" id="intervalMs" value="1000">
+            </div>
+            <div class="form-group">
+                <label class="form-label" style="display:flex;gap:8px;align-items:center">
+                    <input type="checkbox" id="initEnabled" onchange="toggleInitConfig()">
+                    Initial-Call / Session aktivieren
+                </label>
+                <div id="initConfig" style="display:none;margin-top:10px">
+                    <div style="font-size:12px;color:var(--text-secondary);margin-bottom:6px">Läuft beim Programmstart und nach Connect-Klick. Geeignet für RegLogin, Token, Session-ID und globale API-Ergebnisse.</div>
+                    <textarea class="form-textarea js-editor" id="initScript" placeholder="var login = http.postJson(&quot;http://localhost:9000/api/login&quot;, { user: &quot;opc&quot;, password: &quot;secret&quot; });&#10;var result = JSON.parse(login.body);&#10;session.token = result.token;&#10;global.session = result;&#10;global.lastLogin = result;"></textarea>
+                </div>
+            </div>
+            <div class="form-group">
+                <label class="form-label" style="display:flex;gap:8px;align-items:center">
+                    <input type="checkbox" id="conditionEnabled" onchange="toggleConditionConfig()">
+                    Bedingung aktivieren
+                </label>
+                <div id="conditionConfig" style="display:none;margin-top:10px">
+                    <label class="form-label">NodeID-Codebausteine einfügen</label>
+                    <div style="font-size:12px;color:var(--text-secondary);margin-bottom:6px">Die Liste erzeugt nur Code. Beim Speichern ist das Script vollständig eigenständig, z. B. <code>var Temperatur = opc.read(&quot;ns=...&quot;)</code>.</div>
+<div id="conditionNodeList" class="code-helper-list"></div>
+                    <label class="form-label" style="margin-top:10px">Condition JavaScript (muss true/false zurückgeben)</label>
+                    <textarea class="form-textarea js-editor" id="conditionScript" placeholder="var Temperatur = Number(opc.read(&quot;ns=3;s=AirConditioner_1.Temperature&quot;));&#10;Temperatur &gt; 70"></textarea>
+                </div>
+            </div>
+            <div class="form-group">
+                <label class="form-label">NodeID-Codegenerator fuer Hauptscript</label>
+                <div class="code-helper">
+                    <div style="font-size:12px;color:var(--text-secondary)">Checkboxen erzeugen nur feste Codezeilen. Es werden keine Runtime-Variablen aus Checkboxen gespeichert.</div>
+                    <div id="actionNodeCodeList" class="code-helper-list"></div>
+                    <div style="display:flex;gap:6px;flex-wrap:wrap">
+                        <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('actionNodeCodeList','scriptCode','readNumber')">var Number einfuegen</button>
+                        <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('actionNodeCodeList','scriptCode','read')">var Text einfuegen</button>
+                        <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('actionNodeCodeList','scriptCode','write','result.value')">opc.write einfuegen</button>
+                    </div>
+                    <div id="actionTemplateButtons" style="display:flex;gap:6px;flex-wrap:wrap;margin-top:6px"></div>
+                </div>
+                <label class="form-label">JavaScript Code</label>
+                <textarea class="form-textarea js-editor" id="scriptCode" placeholder="var Temperatur = Number(opc.read(&quot;ns=3;s=AirConditioner_1.Temperature&quot;));&#10;var response = http.postJson(&quot;http://localhost:9000/api/check&quot;, { temperature: Temperatur });&#10;var result = JSON.parse(response.body);&#10;opc.write(&quot;ns=3;s=AirConditioner_1.Result&quot;, result.value);"></textarea>
+            </div>
+            <div style="display:flex;gap:8px">
+                <button class="btn" style="flex:1" onclick="saveAction()">Save</button>
+                <button class="btn btn-secondary" style="flex:1" onclick="closeModal()">Cancel</button>
+            </div>
+        </div>
+    </div>
+
+    <!-- Edit Value Modal -->
+    <div class="modal" id="editValueModal">
+        <div class="modal-content">
+            <div class="modal-header">Edit Value</div>
+            <div class="form-group">
+                <label class="form-label">Node ID</label>
+                <input type="text" class="form-input" id="editNodeId" readonly>
+            </div>
+            <div class="form-group">
+                <label class="form-label">New Value</label>
+                <input type="text" class="form-input" id="editValue">
+            </div>
+            <div style="display:flex;gap:8px">
+                <button class="btn btn-success" style="flex:1" onclick="writeValue()">Write</button>
+                <button class="btn btn-secondary" style="flex:1" onclick="closeEditValueModal()">Cancel</button>
+            </div>
+        </div>
+    </div>
+
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.16/codemirror.min.js"></script>
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.16/mode/javascript/javascript.min.js"></script>
+    <script>
+        const API = window.location.origin + '/api';
+        let nodes = [], actions = [], systemInitConfig = {}, scriptTemplates = [], securityConfig = {}, selectedTemplateIndex = -1, isConnected = false, currentNodeForAction = null, autoRefreshInterval = null;
+        let restAuth = { enabled: false, user: 'admin', password: sessionStorage.getItem('opcuaRestPassword') || '' };
+        const jsEditors = {};
+
+        function buildAuthHeaders() {
+            if (!restAuth.enabled || !restAuth.password) return {};
+            return { 'Authorization': 'Basic ' + btoa((restAuth.user || 'admin') + ':' + restAuth.password) };
+        }
+
+        async function apiFetch(path, options = {}) {
+            options.headers = Object.assign({}, options.headers || {}, buildAuthHeaders());
+            let response = await fetch(API + path, options);
+            if (response.status === 401) {
+                const pw = prompt('REST Passwort für Benutzer ' + (restAuth.user || 'admin') + ':');
+                if (pw === null) return response;
+                restAuth.password = pw;
+                sessionStorage.setItem('opcuaRestPassword', pw);
+                options.headers = Object.assign({}, options.headers || {}, buildAuthHeaders());
+                response = await fetch(API + path, options);
+            }
+            return response;
+        }
+
+        async function loadAuthStatus() {
+            try {
+                const d = await (await fetch(API + '/auth/status')).json();
+                restAuth.enabled = !!d.restAuthEnabled;
+                restAuth.user = d.restAuthUser || 'admin';
+            } catch(e) {}
+        }
+
+        // ── Status polling ────────────────────────────────────────────────────
+        setInterval(checkStatus, 5000);
+        loadAuthStatus().then(() => { checkStatus(); loadActions(); loadSystemInit(); loadScriptTemplates(); });
+        checkStatus();
+        setInterval(pollTwinStatus, 4000);
+
+        async function checkStatus() {
+            try {
+                const d = await (await apiFetch('/status')).json();
+                isConnected = d.connected;
+                document.getElementById('statusDot').classList.toggle('connected', isConnected);
+                document.getElementById('statusText').textContent = isConnected ? 'Connected' : 'Disconnected';
+            } catch(e) { isConnected = false; }
+        }
+
+        async function pollTwinStatus() {
+            try {
+                const d = await (await apiFetch('/twin-status')).json();
+                const el = document.getElementById('twinStatus');
+                if (d.ready) {
+                    el.textContent = '✅ Export bereit (' + d.nodeCount + ' Nodes)';
+                } else if (d.building) {
+                    el.textContent = '⏳ Export wird gebaut…';
+                } else {
+                    el.textContent = '';
+                }
+            } catch(e) {}
+        }
+
+        // ── Tree: lazy browse ─────────────────────────────────────────────────
+        async function loadRoot() {
+            if (!isConnected) { alert('Not connected'); return; }
+            const btn = document.getElementById('loadTreeBtn');
+            btn.disabled = true;
+            const container = document.getElementById('treeView');
+            container.innerHTML = '<div style="padding:20px;text-align:center"><span class="spinner"></span> Loading…</div>';
+
+            try {
+                const d = await browseNode(null);
+                container.innerHTML = '';
+                container.appendChild(buildUl(d.children));
+                document.getElementById('treeInfo').textContent = d.children.length + ' root nodes';
+            } catch(e) {
+                container.innerHTML = '<div class="empty-state"><div>Error: ' + e.message + '</div></div>';
+            } finally {
+                btn.disabled = false;
+            }
+        }
+
+        async function browseNode(nodeId) {
+            const r = await apiFetch('/browse-tree', {
+                method: 'POST',
+                headers: {'Content-Type': 'application/json'},
+                body: JSON.stringify(nodeId ? {nodeId} : {})
+            });
+            const d = await r.json();
+            if (!d.success) throw new Error(d.error || 'Browse failed');
+            return d;
+        }
+
+        function buildUl(children) {
+            const ul = document.createElement('div');
+            for (const n of children) {
+                const wrap = document.createElement('div');
+
+                const row = document.createElement('div');
+                row.className = 'tree-node';
+
+                const content = document.createElement('div');
+                content.className = 'tree-node-content';
+
+                // Expand button
+                const expand = document.createElement('div');
+                expand.className = 'tree-expand';
+                expand.textContent = '›';
+                expand.onclick = async (e) => {
+                    e.stopPropagation();
+                    const childContainer = wrap.querySelector('.tree-children');
+                    if (childContainer.classList.contains('show')) {
+                        childContainer.classList.remove('show');
+                        expand.classList.remove('expanded');
+                        return;
+                    }
+                    // Lazy load children
+                    if (childContainer.children.length === 0) {
+                        expand.classList.add('loading-spin');
+                        expand.textContent = '○';
+                        try {
+                            const d = await browseNode(n.nodeId);
+                            if (d.children.length > 0) {
+                                childContainer.appendChild(buildUl(d.children));
+                            } else {
+                                childContainer.innerHTML = '<div style="padding:8px 16px;font-size:12px;color:var(--text-secondary)">No children</div>';
+                            }
+                        } catch(err) {
+                            childContainer.innerHTML = '<div style="padding:8px;color:var(--red)">Error loading</div>';
+                        }
+                        expand.classList.remove('loading-spin');
+                        expand.textContent = '›';
+                    }
+                    childContainer.classList.add('show');
+                    expand.classList.add('expanded');
+                };
+
+                const isVar = n.nodeClass === 'Variable';
+                const icon = isVar ? '📊' : (n.nodeClass === 'View' ? '👁' : '📁');
+
+                const label = document.createElement('span');
+                label.style.flex = '1';
+                label.innerHTML = `<span style="margin-right:6px">${icon}</span><b>${esc(n.displayName || n.browseName)}</b><span style="font-size:11px;color:var(--text-secondary);margin-left:6px">${n.nodeClass || ''}</span>`;
+
+                // Value badge for Variables
+                if (isVar && n.value != null) {
+                    const badge = document.createElement('span');
+                    badge.className = 'value-badge';
+                    badge.textContent = n.value;
+                    label.appendChild(badge);
+                }
+
+                // Click to add to monitoring
+                label.onclick = () => addNode(n.nodeId, n.displayName || n.browseName);
+                label.style.cursor = 'pointer';
+
+                content.appendChild(expand);
+                content.appendChild(label);
+                row.appendChild(content);
+
+                const childContainer = document.createElement('div');
+                childContainer.className = 'tree-children';
+
+                wrap.appendChild(row);
+                wrap.appendChild(childContainer);
+                ul.appendChild(wrap);
+            }
+            return ul;
+        }
+
+        // ── Monitoring table ──────────────────────────────────────────────────
+        function addNode(nodeId, name) {
+            if (nodes.find(n => n.id === nodeId)) { alert('Already added'); return; }
+            const m = nodeId.match(/ns=(\d+);([a-z])=/i);
+            nodes.push({
+                id: nodeId, name,
+                ns:   m ? m[1] : '?',
+                type: m ? (m[2].toLowerCase() === 's' ? 'String' : 'UInteger') : '?',
+                value: '…'
+            });
+            renderTable();
+            readValue(nodeId);
+        }
+
+        async function readValue(nodeId) {
+            try {
+                const d = await (await apiFetch('/read', {
+                    method: 'POST',
+                    headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId})
+                })).json();
+                if (d.success) {
+                    const n = nodes.find(x => x.id === nodeId);
+                    if (n) {
+                        const cell = document.querySelector(`[data-node-id="${nodeId}"] .value-cell`);
+                        if (cell && n.value !== d.value) {
+                            cell.classList.add('updating');
+                            setTimeout(() => cell.classList.remove('updating'), 500);
+                        }
+                        n.value = d.value;
+                        renderTable();
+                    }
+                }
+            } catch(e) {}
+        }
+
+        function renderTable() {
+            const tb = document.getElementById('nodesTableBody');
+            document.getElementById('nodeCount').textContent = nodes.length;
+            if (nodes.length === 0) {
+                tb.innerHTML = '<tr><td colspan="7"><div class="empty-state"><div class="empty-icon">📊</div><div>No nodes — click a tree node to add</div></div></td></tr>';
+                return;
+            }
+            tb.innerHTML = nodes.map((n, i) => `
+                <tr data-node-id="${esc(n.id)}">
+                    <td style="font-weight:600">${esc(n.name)}</td>
+                    <td style="font-size:12px;color:var(--text-secondary)">${esc(n.id)}</td>
+                    <td><span class="badge">${n.ns}</span></td>
+                    <td><span class="badge badge-warning">${n.type}</span></td>
+                    <td><span class="value-cell" onclick="editVal('${esc(n.id)}','${esc(n.value)}')">${esc(n.value)}</span></td>
+                    <td><button class="btn btn-small" onclick="openActions('${esc(n.id)}')">Actions</button></td>
+                    <td><button class="btn-delete" onclick="removeNode(${i})">×</button></td>
+                </tr>`).join('');
+        }
+
+        function removeNode(idx) {
+            if (confirm('Remove ' + nodes[idx].name + '?')) { nodes.splice(idx, 1); renderTable(); }
+        }
+
+        function toggleAutoRefresh() {
+            if (autoRefreshInterval) {
+                clearInterval(autoRefreshInterval);
+                autoRefreshInterval = null;
+                document.getElementById('refreshLabel').textContent = '▶ Live';
+            } else {
+                autoRefreshInterval = setInterval(() => nodes.forEach(n => readValue(n.id)), 2000);
+                document.getElementById('refreshLabel').textContent = '⏹ Stop';
+                nodes.forEach(n => readValue(n.id));
+            }
+        }
+
+        // ── Export ────────────────────────────────────────────────────────────
+        function exportTwin() {
+            window.open(API + '/export', '_blank');
+        }
+
+        // ── Write value ───────────────────────────────────────────────────────
+        function editVal(nodeId, val) {
+            document.getElementById('editNodeId').value = nodeId;
+            document.getElementById('editValue').value = val;
+            document.getElementById('editValueModal').classList.add('active');
+        }
+        function closeEditValueModal() { document.getElementById('editValueModal').classList.remove('active'); }
+
+        async function writeValue() {
+            const nodeId = document.getElementById('editNodeId').value;
+            const value  = document.getElementById('editValue').value;
+            try {
+                const d = await (await apiFetch('/write', {
+                    method: 'POST',
+                    headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId, value})
+                })).json();
+                if (d.success) {
+                    const n = nodes.find(x => x.id === nodeId);
+                    if (n) { n.value = value; renderTable(); }
+                    closeEditValueModal();
+                } else alert('Write failed');
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        // ── System Init / RegLogin ──────────────────────────────────────────────
+        async function loadSecurityConfig() {
+            try {
+                const d = await (await apiFetch('/config/security')).json();
+                if (d.success) {
+                    securityConfig = d;
+                    const dir = document.getElementById('configDirectoryLabel');
+                    const settings = document.getElementById('settingsFileLabel');
+                    if (dir) dir.textContent = d.configDirectory || 'config';
+                    if (settings) settings.textContent = d.settingsFile || 'config/settings.json';
+                    const enc = document.getElementById('configEncryptionEnabled');
+                    const rp = document.getElementById('restAuthEnabled');
+                    const ru = document.getElementById('restAuthUser');
+                    if (enc) enc.checked = !!d.configEncryptionEnabled;
+                    if (rp) rp.checked = !!d.restAuthEnabled;
+                    if (ru) ru.value = d.restAuthUser || 'admin';
+                    const info = document.getElementById('securityInfo');
+                    if (info) info.textContent = 'REST Passwort gesetzt: ' + (d.restAuthPasswordSet ? 'ja' : 'nein') + ' · Config Passwort gesetzt: ' + (d.configEncryptionPasswordSet ? 'ja' : 'nein');
+                }
+            } catch(e) {
+                const info = document.getElementById('securityInfo');
+                if (info) info.textContent = 'Security-Config konnte nicht geladen werden: ' + e.message;
+            }
+        }
+
+        async function saveSecurityConfig() {
+            const payload = {
+                configEncryptionEnabled: document.getElementById('configEncryptionEnabled')?.checked || false,
+                configEncryptionPassword: document.getElementById('configEncryptionPassword')?.value || '',
+                restAuthEnabled: document.getElementById('restAuthEnabled')?.checked || false,
+                restAuthUser: document.getElementById('restAuthUser')?.value || 'admin',
+                restAuthPassword: document.getElementById('restAuthPassword')?.value || ''
+            };
+            const d = await (await apiFetch('/config/security', {
+                method: 'POST',
+                headers: {'Content-Type': 'application/json'},
+                body: JSON.stringify(payload)
+            })).json();
+            if (!d.success) throw new Error(d.error || 'Security speichern fehlgeschlagen');
+            securityConfig = d;
+            restAuth.enabled = !!d.restAuthEnabled && !!d.restAuthPasswordSet;
+            restAuth.user = d.restAuthUser || 'admin';
+            const pw = payload.restAuthPassword;
+            if (pw) {
+                restAuth.password = pw;
+                sessionStorage.setItem('opcuaRestPassword', pw);
+            }
+            document.getElementById('restAuthPassword').value = '';
+            document.getElementById('configDirectoryLabel').textContent = d.configDirectory || 'config';
+            document.getElementById('settingsFileLabel').textContent = d.settingsFile || 'config/settings.json';
+            document.getElementById('securityInfo').textContent = 'Gespeichert. REST Auth: ' + (restAuth.enabled ? 'aktiv' : 'aus');
+        }
+
+        async function loadSystemInit() {
+            try {
+                const d = await (await apiFetch('/system-init')).json();
+                if (d.success) systemInitConfig = Object.assign({}, d.config || {}, {file: d.file});
+            } catch(e) {}
+        }
+
+        async function openConfigurationModal() {
+            await loadAuthStatus();
+            await loadSecurityConfig();
+            await loadSystemInit();
+            await loadScriptTemplates();
+            document.getElementById('systemInitEnabled').checked = !!systemInitConfig.enabled;
+            document.getElementById('systemInitRunAtProgramStart').checked = !!systemInitConfig.runAtProgramStart;
+            document.getElementById('systemInitRunAfterConnect').checked = systemInitConfig.runAfterConnect !== false;
+            setEditorValue('systemInitScript', systemInitConfig.script || '');
+            document.getElementById('systemInitPathLabel').textContent = systemInitConfig.file || 'config/system-init-script.json';
+            document.getElementById('systemInitInfo').textContent = systemInitConfig.updatedAt ? ('Zuletzt gespeichert: ' + new Date(systemInitConfig.updatedAt).toLocaleString()) : '';
+            document.getElementById('systemInitModal').classList.add('active');
+            ensureEditor('systemInitScript');
+            ensureEditor('scriptTemplateCode');
+            renderScriptTemplateList();
+            setTimeout(() => { 
+                if (jsEditors.systemInitScript) jsEditors.systemInitScript.refresh();
+                if (jsEditors.scriptTemplateCode) jsEditors.scriptTemplateCode.refresh();
+            }, 50);
+        }
+
+        function insertRegLoginTemplate() {
+            insertAtCursor('systemInitScript', `var response = http.postJson("http://localhost:9000/api/reglogin", {
+  client: "opcua-client",
+  user: "opc",
+  password: "secret"
+});
+
+if (response.status < 200 || response.status >= 300) {
+  throw "RegLogin failed: HTTP " + response.status + " / " + response.body;
+}
+
+var result = JSON.parse(response.body);
+global.session = result;
+global.token = result.token;
+global.apiResult = result;
+log.info("RegLogin OK");
+`);
+        }
+
+        async function saveConfiguration() {
+            try { await saveSecurityConfig(); } catch(e) { alert('Security speichern Fehler: ' + e.message); return; }
+            await saveSystemInit(false);
+            await saveScriptTemplates(false);
+            closeSystemInitModal();
+        }
+
+        function closeSystemInitModal() {
+            document.getElementById('systemInitModal').classList.remove('active');
+        }
+
+        async function saveSystemInit(runAfterSave) {
+            const payload = {
+                enabled: document.getElementById('systemInitEnabled').checked,
+                runAtProgramStart: document.getElementById('systemInitRunAtProgramStart').checked,
+                runAfterConnect: document.getElementById('systemInitRunAfterConnect').checked,
+                script: getEditorValue('systemInitScript')
+            };
+            try {
+                const d = await (await apiFetch('/system-init', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify(payload)
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Save failed');
+                systemInitConfig = Object.assign({}, d.config || payload, {file: d.file});
+                const file = d.file || 'config/system-init-script.json';
+                document.getElementById('systemInitPathLabel').textContent = file;
+                document.getElementById('systemInitInfo').textContent = 'Gespeichert in: ' + file;
+                if (runAfterSave) await runSystemInit();
+            } catch(e) { alert('System Init Fehler: ' + e.message); }
+        }
+
+        async function runSystemInit() {
+            try {
+                const d = await (await apiFetch('/system-init/run', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({reason: 'manual-ui', force: true})
+                })).json();
+                if (!d.success && !d.skipped) throw new Error(d.error || 'Run failed');
+                document.getElementById('systemInitInfo').textContent = d.skipped
+                    ? ('Nicht ausgeführt: ' + (d.message || 'skipped'))
+                    : ('Ausgeführt. Globals: ' + JSON.stringify(d.globals || {}));
+            } catch(e) { alert('System Init Run Fehler: ' + e.message); }
+        }
+
+
+        // ── Script Templates ───────────────────────────────────────────────────
+        async function loadScriptTemplates() {
+            try {
+                const d = await (await apiFetch('/script/templates')).json();
+                if (d.success) {
+                    scriptTemplates = d.templates || [];
+                    const path = document.getElementById('scriptTemplatePathLabel');
+                    if (path) path.textContent = d.file || 'config/script-templates.json';
+                }
+            } catch(e) {}
+        }
+
+        function commitSelectedTemplate() {
+            if (selectedTemplateIndex < 0 || selectedTemplateIndex >= scriptTemplates.length) return;
+            const t = scriptTemplates[selectedTemplateIndex];
+            const nameEl = document.getElementById('scriptTemplateName');
+            const enabledEl = document.getElementById('scriptTemplateEnabled');
+            if (nameEl) t.name = nameEl.value || 'Template';
+            if (enabledEl) t.enabled = !!enabledEl.checked;
+            t.script = getEditorValue('scriptTemplateCode');
+            t.updatedAt = Date.now();
+        }
+
+        function renderScriptTemplateList() {
+            const list = document.getElementById('scriptTemplateList');
+            if (!list) return;
+            if (!scriptTemplates.length) {
+                list.innerHTML = '<div style="padding:12px;color:var(--text-secondary)">Keine Templates vorhanden.</div>';
+                selectedTemplateIndex = -1;
+                setTemplateForm(null);
+                return;
+            }
+            if (selectedTemplateIndex < 0 || selectedTemplateIndex >= scriptTemplates.length) selectedTemplateIndex = 0;
+            list.innerHTML = scriptTemplates.map((t, i) => `
+                <div class="template-list-item ${i === selectedTemplateIndex ? 'active' : ''}" onclick="selectScriptTemplate(${i})">
+                    <span>${t.enabled === false ? '○' : '●'} ${esc(t.name || 'Template')}</span>
+                    <span style="color:var(--text-secondary);font-size:11px">${t.builtIn ? 'Standard' : 'Eigen'}</span>
+                </div>`).join('');
+            setTemplateForm(scriptTemplates[selectedTemplateIndex]);
+        }
+
+        function setTemplateForm(t) {
+            const nameEl = document.getElementById('scriptTemplateName');
+            const enabledEl = document.getElementById('scriptTemplateEnabled');
+            if (nameEl) nameEl.value = t ? (t.name || '') : '';
+            if (enabledEl) enabledEl.checked = !t || t.enabled !== false;
+            setEditorValue('scriptTemplateCode', t ? (t.script || '') : '');
+        }
+
+        function selectScriptTemplate(index) {
+            commitSelectedTemplate();
+            selectedTemplateIndex = index;
+            renderScriptTemplateList();
+            if (jsEditors.scriptTemplateCode) setTimeout(() => jsEditors.scriptTemplateCode.refresh(), 20);
+        }
+
+        function newScriptTemplate() {
+            commitSelectedTemplate();
+            scriptTemplates.push({
+                id: '', name: 'Neues Template', enabled: true, builtIn: false, updatedAt: Date.now(),
+                script: `// Eigenes Template\n// Die Platzhalter werden beim Einfügen durch feste NodeID-Codezeilen ersetzt.\n{{readNumberVars}}\n\nvar response = http.postJson("http://localhost:9000/api/process", {\n{{payloadFields}}});\n\nvar result = JSON.parse(response.body);\nglobal.apiResult = result;\n{{opcWritesFromResult}}\n`
+            });
+            selectedTemplateIndex = scriptTemplates.length - 1;
+            renderScriptTemplateList();
+        }
+
+        function deleteScriptTemplate() {
+            if (selectedTemplateIndex < 0) return;
+            if (!confirm('Template löschen?')) return;
+            scriptTemplates.splice(selectedTemplateIndex, 1);
+            selectedTemplateIndex = Math.min(selectedTemplateIndex, scriptTemplates.length - 1);
+            renderScriptTemplateList();
+        }
+
+        async function resetScriptTemplates() {
+            if (!confirm('Standard GET/POST/SET wiederherstellen? Eigene Template-Änderungen werden ersetzt.')) return;
+            try {
+                const d = await (await apiFetch('/script/templates', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify({resetDefaults: true})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Reset failed');
+                scriptTemplates = d.templates || [];
+                selectedTemplateIndex = 0;
+                renderScriptTemplateList();
+                renderActionTemplateButtons();
+            } catch(e) { alert('Template Reset Fehler: ' + e.message); }
+        }
+
+        async function saveScriptTemplates(showMessage = true) {
+            commitSelectedTemplate();
+            try {
+                const d = await (await apiFetch('/script/templates', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify({templates: scriptTemplates})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Save failed');
+                scriptTemplates = d.templates || [];
+                renderScriptTemplateList();
+                renderActionTemplateButtons();
+                if (showMessage) alert('Templates gespeichert');
+            } catch(e) { alert('Templates speichern Fehler: ' + e.message); }
+        }
+
+        function insertTemplatePlaceholders() {
+            insertAtCursor('scriptTemplateCode', `\n// Platzhalter:\n{{readNumberVars}}\n{{payloadFields}}\n{{opcWritesFromResult}}\n`);
+        }
+
+        async function renderActionTemplateButtons() {
+            const box = document.getElementById('actionTemplateButtons');
+            if (!box) return;
+            if (!scriptTemplates.length) await loadScriptTemplates();
+            const active = scriptTemplates.filter(t => t.enabled !== false);
+            if (!active.length) {
+                box.innerHTML = '<span style="font-size:12px;color:var(--text-secondary)">Keine aktiven Templates. Unter Configuration → Script Templates anlegen.</span>';
+                return;
+            }
+            box.innerHTML = active.map(t => `<button type="button" class="btn btn-small" onclick="insertUserTemplate('${escAttr(t.id || t.name)}')">${esc(t.name || 'Template')}</button>`).join('');
+        }
+
+        async function insertUserTemplate(templateId) {
+            const selected = getCheckedNodeSpecs('actionNodeCodeList');
+            try {
+                const d = await (await apiFetch('/script/template-snippet', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({templateId, nodes: selected})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Template failed');
+                insertAtCursor('scriptCode', d.script);
+            } catch(e) { alert('Template Fehler: ' + e.message); }
+        }
+
+        // ── Actions ───────────────────────────────────────────────────────────
+        async function openActions(nodeId) {
+            currentNodeForAction = nodeId;
+            await loadScriptTemplates();
+            renderConditionNodeList();
+            renderNodeCodeList('actionNodeCodeList');
+            renderActionTemplateButtons();
+            document.getElementById('actionModal').classList.add('active');
+            ['initScript','conditionScript','scriptCode'].forEach(ensureEditor);
+        }
+        function closeModal() { document.getElementById('actionModal').classList.remove('active'); }
+
+        function updateTriggerFields() {
+            const t = document.getElementById('triggerType').value;
+            document.getElementById('triggerValueGroup').style.display =
+                ['ON_VALUE','ON_GREATER_THAN','ON_LESS_THAN'].includes(t) ? 'block' : 'none';
+            document.getElementById('intervalGroup').style.display =
+                t === 'ON_INTERVAL' ? 'block' : 'none';
+        }
+
+        function toggleConditionConfig() {
+            document.getElementById('conditionConfig').style.display =
+                document.getElementById('conditionEnabled').checked ? 'block' : 'none';
+        }
+
+        function toggleInitConfig() {
+            document.getElementById('initConfig').style.display =
+                document.getElementById('initEnabled').checked ? 'block' : 'none';
+        }
+
+        function renderConditionNodeList() {
+            renderNodeCodeList('conditionNodeList');
+            const box = document.getElementById('conditionNodeList');
+            if (box && nodes.length) {
+                const buttons = document.createElement('div');
+                buttons.style.display = 'flex';
+                buttons.style.gap = '6px';
+                buttons.style.flexWrap = 'wrap';
+                buttons.style.marginTop = '8px';
+                buttons.innerHTML = `
+                    <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('conditionNodeList','conditionScript','readNumber')">var Number in Bedingung</button>
+                    <button type="button" class="btn btn-small" onclick="insertCheckedNodeSnippets('conditionNodeList','conditionScript','read')">var Text in Bedingung</button>`;
+                box.appendChild(buttons);
+            }
+        }
+
+        function renderNodeCodeList(containerId) {
+            const box = document.getElementById(containerId);
+            if (!box) return;
+            if (!nodes.length) {
+                box.innerHTML = '<div style="font-size:12px;color:var(--text-secondary)">Keine ueberwachten Nodes vorhanden.</div>';
+                return;
+            }
+            box.innerHTML = nodes.map((n, i) => {
+                const alias = safeAlias(n.name || n.id);
+                return `<label class="code-helper-row">
+                    <input type="checkbox" data-node-id="${esc(n.id)}" checked>
+                    <input class="code-helper-alias" value="${esc(alias)}" title="Variablenname im erzeugten Script">
+                    <span style="font-size:11px;color:var(--text-secondary);overflow:hidden;text-overflow:ellipsis">${esc(n.id)}</span>
+                </label>`;
+            }).join('');
+        }
+
+        function getCheckedNodeSpecs(containerId) {
+            const box = document.getElementById(containerId);
+            if (!box) return [];
+            return [...box.querySelectorAll('input[type="checkbox"][data-node-id]:checked')].map(cb => {
+                const row = cb.closest('.code-helper-row');
+                const aliasInput = row ? row.querySelector('.code-helper-alias') : null;
+                return { nodeId: cb.dataset.nodeId, alias: aliasInput ? aliasInput.value : undefined };
+            });
+        }
+
+        async function insertCheckedNodeSnippets(containerId, targetId, mode, writeExpression) {
+            const selected = getCheckedNodeSpecs(containerId);
+            if (!selected.length) { alert('Keine Node markiert'); return; }
+            try {
+                const d = await (await apiFetch('/script/snippet', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({mode, nodes: selected, writeExpression})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Snippet failed');
+                insertAtCursor(targetId, d.script);
+            } catch(e) {
+                alert('Snippet Fehler: ' + e.message);
+            }
+        }
+
+        function selectedConditionNodes() {
+            // Keinen Runtime-Zustand aus Checkboxen speichern. Die NodeIDs stehen explizit im Script.
+            return {ids: [], aliases: {}};
+        }
+
+        function insertNodeSnippet(btn) {
+            const target = btn.dataset.target;
+            const nodeId = btn.dataset.nodeId;
+            const alias = safeAlias(btn.dataset.alias || nodeId);
+            let snippet;
+            if (btn.dataset.mode === 'readNumber') {
+                snippet = `var ${alias} = Number(opc.read(${JSON.stringify(nodeId)}));\n`;
+            } else if (btn.dataset.mode === 'write') {
+                snippet = `opc.write(${JSON.stringify(nodeId)}, /* value */);\n`;
+            } else {
+                snippet = `var ${alias} = opc.read(${JSON.stringify(nodeId)});\n`;
+            }
+            insertAtCursor(target, snippet);
+        }
+
+        function ensureEditor(id) {
+            const el = document.getElementById(id);
+            if (!el || jsEditors[id]) return jsEditors[id];
+            if (window.CodeMirror) {
+                jsEditors[id] = CodeMirror.fromTextArea(el, {
+                    mode: 'javascript', theme: 'material-darker', lineNumbers: true,
+                    lineWrapping: false, indentUnit: 2, tabSize: 2
+                });
+            }
+            return jsEditors[id];
+        }
+
+        function getEditorValue(id) {
+            return jsEditors[id] ? jsEditors[id].getValue() : (document.getElementById(id)?.value || '');
+        }
+
+        function setEditorValue(id, value) {
+            if (jsEditors[id]) jsEditors[id].setValue(value || '');
+            else { const el = document.getElementById(id); if (el) el.value = value || ''; }
+        }
+
+        function insertAtCursor(elementId, text) {
+            const cm = jsEditors[elementId];
+            if (cm) {
+                cm.replaceSelection(text);
+                cm.focus();
+                return;
+            }
+            const el = document.getElementById(elementId);
+            if (!el) return;
+            const start = el.selectionStart ?? el.value.length;
+            const end = el.selectionEnd ?? el.value.length;
+            el.value = el.value.slice(0, start) + text + el.value.slice(end);
+            const pos = start + text.length;
+            el.focus();
+            el.setSelectionRange(pos, pos);
+        }
+
+        async function loadActions() {
+            try {
+                const d = await (await apiFetch('/actions')).json();
+                if (d.success) {
+                    actions = d.actions || [];
+                    renderActions();
+                }
+            } catch(e) {}
+        }
+
+        async function saveAction() {
+            const a = {
+                nodeId:   currentNodeForAction,
+                name:     document.getElementById('actionName').value,
+                trigger:  document.getElementById('triggerType').value,
+                value:    document.getElementById('triggerValue').value,
+                interval: document.getElementById('intervalMs').value,
+                initEnabled: document.getElementById('initEnabled').checked,
+                initScript: getEditorValue('initScript'),
+                conditionEnabled: document.getElementById('conditionEnabled').checked,
+                conditionScript: getEditorValue('conditionScript'),
+                conditionNodeIds: [],
+                nodeAliases: {},
+                script:   getEditorValue('scriptCode')
+            };
+            if (!a.name || !a.script) { alert('Name and Script required!'); return; }
+            try {
+                const d = await (await apiFetch('/actions', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify(a)
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Save action failed');
+                await loadActions();
+                closeModal();
+                document.getElementById('actionName').value = '';
+                setEditorValue('scriptCode', '');
+                setEditorValue('initScript', '');
+                document.getElementById('initEnabled').checked = false;
+                toggleInitConfig();
+                setEditorValue('conditionScript', '');
+                document.getElementById('conditionEnabled').checked = false;
+                toggleConditionConfig();
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        function renderActions() {
+            const al = document.getElementById('actionsList');
+            document.getElementById('actionCount').textContent = actions.length;
+            if (actions.length === 0) {
+                al.innerHTML = '<div class="empty-state"><div class="empty-icon">⚡</div><div>No actions</div></div>';
+                return;
+            }
+            al.innerHTML = actions.map((a, i) => `
+                <div class="list-item">
+                    <div>
+                        <div style="font-weight:600">${esc(a.actionName || a.name)}</div>
+                        <div style="font-size:12px;color:var(--text-secondary);margin-top:4px">
+                            ${esc(a.triggerType || a.trigger)} · ${esc(a.nodeId || '')}
+                            ${a.initEnabled ? ' · init/session' : ''}
+                            ${a.conditionEnabled ? ' · condition' : ''}
+                        </div>
+                    </div>
+                    <div style="display:flex;gap:6px">
+                        <button class="btn btn-small" onclick="testAction(${i})">Test</button>
+                        <button class="btn-delete" onclick="deleteAction(${i})">×</button>
+                    </div>
+                </div>`).join('');
+        }
+
+        async function testAction(i) {
+            const a = actions[i];
+            try {
+                const d = await (await apiFetch('/actions/test', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId: a.nodeId, actionName: a.actionName || a.name, value: 'TEST'})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Test failed');
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        async function deleteAction(i) {
+            const a = actions[i];
+            if (!confirm('Delete: ' + (a.actionName || a.name) + '?')) return;
+            try {
+                const d = await (await apiFetch('/actions/delete', {
+                    method: 'POST', headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({nodeId: a.nodeId, actionName: a.actionName || a.name})
+                })).json();
+                if (!d.success) throw new Error(d.error || 'Delete failed');
+                await loadActions();
+            } catch(e) { alert('Error: ' + e.message); }
+        }
+
+        function safeAlias(s) {
+            s = (s || 'node').toString().replace(/[^A-Za-z0-9_$]/g, '_');
+            return /^[A-Za-z_$]/.test(s) ? s : 'n_' + s;
+        }
+
+        function esc(s) {
+            if (!s) return '';
+            return s.toString().replace(/[&<>"']/g, m =>
+                ({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;',"'":'&#039;'}[m]));
+        }
+
+        function escAttr(s) {
+            return esc(s).replace(/`/g, '&#096;');
+        }
+    </script>
+</body>
+</html>
\ No newline at end of file
diff --git a/target/config/actions.json b/target/config/actions.json
new file mode 100644
index 0000000..8878e54
--- /dev/null
+++ b/target/config/actions.json
@@ -0,0 +1 @@
+[ ]
\ No newline at end of file
diff --git a/target/config/script-templates.json b/target/config/script-templates.json
new file mode 100644
index 0000000..356b2d0
--- /dev/null
+++ b/target/config/script-templates.json
@@ -0,0 +1,22 @@
+[ {
+  "id" : "get",
+  "name" : "GET",
+  "script" : "// GET Template: OPC-UA Werte lesen, REST GET aufrufen, Ergebnis global merken\n{{readNumberVars}}\nvar query = {\n{{payloadFields}}  eventNode: event.nodeId,\n  eventValue: currentValue\n};\n\nvar url = \"http://localhost:9000/api/process?\" + Object.keys(query)\n  .map(function(k) { return encodeURIComponent(k) + \"=\" + encodeURIComponent(String(query[k])); })\n  .join(\"&\");\n\nvar response = http.get(url, {\n  Authorization: \"Bearer \" + (global.session && global.session.token ? global.session.token : \"\")\n});\n\nif (response.status < 200 || response.status >= 300) {\n  global.apiResult = { ok: false, status: response.status, body: response.body };\n  throw \"REST Fehler HTTP \" + response.status + \": \" + response.body;\n}\n\nvar result = JSON.parse(response.body);\nglobal.apiResult = result;\nlog.info(\"GET Ergebnis in global.apiResult gespeichert\");\n\n// Optional direkt in OPC-UA schreiben:\n{{opcWritesFromResult}}\n",
+  "enabled" : true,
+  "builtIn" : true,
+  "updatedAt" : 1778514770324
+}, {
+  "id" : "post",
+  "name" : "POST",
+  "script" : "// POST Template: OPC-UA Werte lesen, REST POST senden, Ergebnis global merken\n{{readNumberVars}}\nvar payload = {\n{{payloadFields}}  eventNode: event.nodeId,\n  eventValue: currentValue,\n  timestamp: new Date().toISOString()\n};\n\nvar response = http.postJson(\"http://localhost:9000/api/process\", payload, {\n  Authorization: \"Bearer \" + (global.session && global.session.token ? global.session.token : \"\")\n});\n\nif (response.status < 200 || response.status >= 300) {\n  global.apiResult = { ok: false, status: response.status, body: response.body };\n  throw \"REST Fehler HTTP \" + response.status + \": \" + response.body;\n}\n\nvar result = JSON.parse(response.body);\nglobal.apiResult = result;\nlog.info(\"POST Ergebnis in global.apiResult gespeichert\");\n\n// Optional direkt in OPC-UA schreiben:\n{{opcWritesFromResult}}\n",
+  "enabled" : true,
+  "builtIn" : true,
+  "updatedAt" : 1778514770324
+}, {
+  "id" : "set",
+  "name" : "SET / opc.write",
+  "script" : "// SET Template: Ergebnis aus global.apiResult per opc.write in OPC-UA Nodes schreiben\nvar result = global.apiResult;\nif (!result) {\n  throw \"global.apiResult ist leer. Vorher GET/POST/API-Call oder RegLogin ausfuehren.\";\n}\n\n{{opcWritesFromResult}}\nlog.info(\"OPC-UA SET abgeschlossen\");\n",
+  "enabled" : true,
+  "builtIn" : true,
+  "updatedAt" : 1778514770324
+} ]
\ No newline at end of file
diff --git a/target/config/settings.json b/target/config/settings.json
new file mode 100644
index 0000000..a13284c
--- /dev/null
+++ b/target/config/settings.json
@@ -0,0 +1,14 @@
+{
+  "scriptLogLevel" : "INFO",
+  "Endpoint" : "opc.tcp://opcua.123mc.com:4840",
+  "httpEnabled" : true,
+  "keystorePassword" : "",
+  "httpsEnabled" : false,
+  "httpPort" : 8081,
+  "keystoreType" : "JKS",
+  "scriptLoggingEnabled" : true,
+  "Host" : "http://localhost:8080",
+  "httpsPort" : 8443,
+  "scriptLogDirectory" : "/home/chris/.opcua-gui/logs",
+  "keystorePath" : ""
+}
\ No newline at end of file
diff --git a/target/javafx-jars/javafx-base-21-linux.jar b/target/javafx-jars/javafx-base-21-linux.jar
new file mode 100644
index 0000000..84a597a
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diff --git a/target/javafx-jars/javafx-base-21-mac.jar b/target/javafx-jars/javafx-base-21-mac.jar
new file mode 100644
index 0000000..f63eba7
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diff --git a/target/javafx-jars/javafx-base-21-win.jar b/target/javafx-jars/javafx-base-21-win.jar
new file mode 100644
index 0000000..c5000ba
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diff --git a/target/javafx-jars/javafx-controls-21-linux.jar b/target/javafx-jars/javafx-controls-21-linux.jar
new file mode 100644
index 0000000..6236ee3
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diff --git a/target/javafx-jars/javafx-controls-21-mac.jar b/target/javafx-jars/javafx-controls-21-mac.jar
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index 0000000..fefea3f
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diff --git a/target/javafx-jars/javafx-controls-21-win.jar b/target/javafx-jars/javafx-controls-21-win.jar
new file mode 100644
index 0000000..e63d83d
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diff --git a/target/javafx-jars/javafx-fxml-21-linux.jar b/target/javafx-jars/javafx-fxml-21-linux.jar
new file mode 100644
index 0000000..e22ff0a
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diff --git a/target/javafx-jars/javafx-fxml-21-mac.jar b/target/javafx-jars/javafx-fxml-21-mac.jar
new file mode 100644
index 0000000..99a81fe
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diff --git a/target/javafx-jars/javafx-fxml-21-win.jar b/target/javafx-jars/javafx-fxml-21-win.jar
new file mode 100644
index 0000000..cbc85fc
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diff --git a/target/javafx-jars/javafx-graphics-21-linux.jar b/target/javafx-jars/javafx-graphics-21-linux.jar
new file mode 100644
index 0000000..231dfc0
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diff --git a/target/javafx-jars/javafx-graphics-21-mac.jar b/target/javafx-jars/javafx-graphics-21-mac.jar
new file mode 100644
index 0000000..bf366b5
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diff --git a/target/javafx-jars/javafx-graphics-21-win.jar b/target/javafx-jars/javafx-graphics-21-win.jar
new file mode 100644
index 0000000..6ce774e
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diff --git a/target/maven-archiver/pom.properties b/target/maven-archiver/pom.properties
new file mode 100644
index 0000000..658b236
--- /dev/null
+++ b/target/maven-archiver/pom.properties
@@ -0,0 +1,3 @@
+artifactId=opcua-gui
+groupId=de.opcua
+version=1.0.0
diff --git a/target/maven-status/maven-compiler-plugin/compile/default-compile/createdFiles.lst b/target/maven-status/maven-compiler-plugin/compile/default-compile/createdFiles.lst
new file mode 100644
index 0000000..26ba3a0
--- /dev/null
+++ b/target/maven-status/maven-compiler-plugin/compile/default-compile/createdFiles.lst
@@ -0,0 +1,83 @@
+de/opcua/app/model/NodeAction.class
+de/opcua/app/rest/OpcUaRestApi$RunSystemInitHandler.class
+de/opcua/app/MainApp.class
+de/opcua/app/config/Settings.class
+de/opcua/app/ui/JavaScriptEditorPane.class
+de/opcua/app/rest/OpcUaRestApi$HealthHandler.class
+de/opcua/app/scripting/ScriptSnippetBuilder$NodeSpec.class
+de/opcua/app/RestApiLauncher.class
+de/opcua/app/ui/EditableValueCellFactory$EditableValueCell.class
+de/opcua/app/model/SystemInitScript.class
+de/opcua/app/scripting/Store.class
+de/opcua/app/logging/ScriptLogger$Level.class
+de/opcua/app/scripting/ScriptService.class
+de/opcua/app/model/TreeNodeRef.class
+de/opcua/app/rest/OpcUaRestApi$BrowseHandler.class
+de/opcua/app/rest/OpcUaRestApi$EnableActionHandler.class
+de/opcua/app/rest/OpcUaRestApi$ScriptTemplateSnippetHandler.class
+de/opcua/app/scripting/GraalScriptEngine$OpcUaFacade.class
+de/opcua/app/model/NodeAction$TriggerType.class
+de/opcua/app/rest/OpcUaRestApi$ExportHandler.class
+de/opcua/app/scripting/GraalScriptEngine.class
+de/opcua/app/rest/OpcUaRestApi$BrowseTreeHandler.class
+de/opcua/app/rest/OpcUaRestApi$TwinStatusHandler.class
+de/opcua/app/ui/MainController.class
+de/opcua/app/ui/MainController$1.class
+de/opcua/app/config/AppPaths.class
+de/opcua/app/rest/OpcUaRestApi$HelpPageHandler.class
+de/opcua/app/scripting/GraalScriptEngine$RestResponse.class
+de/opcua/app/rest/OpcUaRestApi$StatusHandler.class
+de/opcua/app/service/ActionPersistenceService$1.class
+de/opcua/app/service/ActionPersistenceService$ActionData.class
+de/opcua/app/rest/OpcUaRestApi$ReadHandler.class
+de/opcua/app/rest/OpenApiHandler.class
+de/opcua/app/rest/OpcUaRestApi$BaseHandler.class
+de/opcua/app/ui/ConfigController.class
+de/opcua/app/rest/OpcUaRestApi$SystemInitHandler.class
+de/opcua/app/ui/MainController$EditableValueCell.class
+de/opcua/app/rest/OpcUaRestApi$StaticAssetHandler.class
+de/opcua/app/scripting/GraalScriptEngine$Console.class
+de/opcua/app/rest/OpcUaRestApi$GlobalsHandler.class
+de/opcua/app/rest/OpcUaRestApi$WebInterfaceHandler.class
+de/opcua/app/rest/OpcUaRestApi.class
+de/opcua/app/rest/OpcUaRestApi$DeleteActionHandler.class
+de/opcua/app/config/ConfigSecurity.class
+de/opcua/app/scripting/ScriptSnippetBuilder.class
+de/opcua/app/rest/OpcUaRestApi$ConfigSecurityHandler.class
+de/opcua/app/service/AppMode.class
+de/opcua/app/model/NodeRow.class
+de/opcua/app/service/ScriptTemplateService.class
+de/opcua/app/rest/OpcUaRestApi$ScriptSnippetHandler.class
+de/opcua/app/rest/HelpPageHandler.class
+de/opcua/app/rest/OpcUaRestApi$FaviconHandler.class
+de/opcua/app/service/ScriptTemplateService$1.class
+de/opcua/app/service/ActionPersistenceService.class
+de/opcua/app/UiApp.class
+de/opcua/app/ServiceMain.class
+de/opcua/app/ui/ActionButtonHelper$1.class
+de/opcua/app/ui/EditableValueCellFactory$EditableValueCell$1.class
+de/opcua/app/rest/OpcUaRestApi$AuthStatusHandler.class
+de/opcua/app/scripting/GraalScriptEngine$Log.class
+de/opcua/app/service/SystemInitScriptService.class
+de/opcua/app/scripting/GraalScriptEngine$ScriptExecutionException.class
+de/opcua/app/ui/ActionButtonHelper.class
+de/opcua/app/config/SettingsService.class
+de/opcua/app/ui/ActionButtonHelper$2.class
+de/opcua/app/scripting/GraalScriptEngine$RestClient.class
+de/opcua/app/ui/EditableValueCellFactory.class
+de/opcua/app/rest/OpcUaRestApi$ActionsHandler.class
+de/opcua/app/scripting/GraalScriptEngine$SleepFunction.class
+de/opcua/app/model/ScriptTemplate.class
+de/opcua/app/scripting/GraalScriptEngine$SharedScope.class
+de/opcua/app/test/MinimalRestTest.class
+de/opcua/app/rest/OpcUaRestApi$InitActionsHandler.class
+de/opcua/app/service/ActionService.class
+de/opcua/app/rest/OpcUaRestApi$WriteHandler.class
+de/opcua/app/ui/ConfigController$1.class
+de/opcua/app/rest/OpcUaRestApi$ScriptTemplatesHandler.class
+de/opcua/app/rest/OpcUaRestApi$OpenApiHandler.class
+de/opcua/app/logging/ScriptLogger.class
+de/opcua/app/opc/OpcUaService.class
+de/opcua/app/rest/OpcUaRestApi$TestActionHandler.class
+de/opcua/app/ui/MainController$JsOpcBridge.class
+de/opcua/app/Launcher.class
diff --git a/target/maven-status/maven-compiler-plugin/compile/default-compile/inputFiles.lst b/target/maven-status/maven-compiler-plugin/compile/default-compile/inputFiles.lst
new file mode 100644
index 0000000..d46624c
--- /dev/null
+++ b/target/maven-status/maven-compiler-plugin/compile/default-compile/inputFiles.lst
@@ -0,0 +1,34 @@
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/UiApp.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/MainApp.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/scripting/ScriptService.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/ServiceMain.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/model/ScriptTemplate.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/ui/EditableValueCellFactory.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/model/NodeRow.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/scripting/GraalScriptEngine.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/model/TreeNodeRef.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/rest/OpcUaRestApi.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/Launcher.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/logging/ScriptLogger.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/scripting/Store.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/ui/ConfigController.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/model/NodeAction.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/service/AppMode.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/ui/ActionButtonHelper.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/config/AppPaths.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/ui/MainController.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/service/ActionPersistenceService.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/scripting/ScriptSnippetBuilder.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/config/ConfigSecurity.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/config/SettingsService.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/service/ActionService.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/ui/JavaScriptEditorPane.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/rest/HelpPageHandler.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/service/ScriptTemplateService.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/test/MinimalRestTest.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/RestApiLauncher.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/config/Settings.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/model/SystemInitScript.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/opc/OpcUaService.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/rest/OpenApiHandler.java
+/home/chris/DevJava/opcua_client/src/main/java/de/opcua/app/service/SystemInitScriptService.java
diff --git a/target/opcua-gui-1.0.0.jar b/target/opcua-gui-1.0.0.jar
new file mode 100644
index 0000000..62e093f
Binary files /dev/null and b/target/opcua-gui-1.0.0.jar differ
diff --git a/target/original-opcua-gui-1.0.0.jar b/target/original-opcua-gui-1.0.0.jar
new file mode 100644
index 0000000..35c7d3d
Binary files /dev/null and b/target/original-opcua-gui-1.0.0.jar differ
diff --git a/windows-service/OPCUAClientService.xml b/windows-service/OPCUAClientService.xml
new file mode 100644
index 0000000..8911617
--- /dev/null
+++ b/windows-service/OPCUAClientService.xml
@@ -0,0 +1,23 @@
+<service>
+  <id>OPCUAClient</id>
+  <name>OPC UA Client Service</name>
+  <description>OPC UA Client REST API, RegLogin/System Init and Action Engine</description>
+
+  <!-- Java must be available in PATH or set JAVA_HOME in service environment. -->
+  <executable>java</executable>
+  <arguments>-jar "%BASE%\opcua-gui-1.0.0.jar" --service</arguments>
+  <workingdirectory>%BASE%</workingdirectory>
+
+  <logpath>%BASE%\logs</logpath>
+  <log mode="roll-by-size">
+    <sizeThreshold>10485760</sizeThreshold>
+    <keepFiles>8</keepFiles>
+  </log>
+
+  <onfailure action="restart" delay="10 sec"/>
+  <onfailure action="restart" delay="30 sec"/>
+  <onfailure action="none"/>
+
+  <startmode>Automatic</startmode>
+  <stoptimeout>30 sec</stoptimeout>
+</service>
diff --git a/windows-service/README.md b/windows-service/README.md
new file mode 100644
index 0000000..26871f6
--- /dev/null
+++ b/windows-service/README.md
@@ -0,0 +1,76 @@
+# Windows Service Wrapper
+
+Dieser Ordner enthält eine WinSW-Konfiguration für den OPC UA Client im Service-Modus.
+
+## Dateien
+
+- `OPCUAClientService.xml` - WinSW-Konfiguration
+- `install-service.bat` - Dienst installieren
+- `uninstall-service.bat` - Dienst entfernen
+- `start-service.bat` - Dienst starten
+- `stop-service.bat` - Dienst stoppen
+- `status-service.bat` - Dienststatus anzeigen
+- `prepare-service-folder.bat` - JAR bauen und in diesen Ordner kopieren
+- `build-exe.bat` - Windows-EXE per Launch4j-Profil bauen
+
+## Installation
+
+1. Projekt bauen und Service-Ordner vorbereiten:
+
+```bat
+windows-service\prepare-service-folder.bat
+```
+
+2. `WinSW-x64.exe` von den WinSW Releases herunterladen und in diesen Ordner legen.
+
+3. Eingabeaufforderung als Administrator öffnen:
+
+```bat
+cd windows-service
+install-service.bat
+start-service.bat
+status-service.bat
+```
+
+Der Service startet:
+
+```bat
+java -jar opcua-gui-1.0.0.jar --service
+```
+
+Das globale System-Init-/RegLogin-Script wird im Service-Modus nach erfolgreichem OPC-Connect/Reconnect ausgeführt, wenn es in der Weboberfläche aktiviert wurde.
+
+## EXE bauen
+
+```bat
+windows-service\build-exe.bat
+```
+
+Ergebnis:
+
+```text
+target\opcua-gui.exe
+```
+
+## Portable Konfiguration
+
+Ab dieser Version liegen alle Laufzeit-Konfigurationen im Unterordner `config` neben der Anwendung beziehungsweise neben der EXE/JAR:
+
+- `config/settings.json`
+- `config/actions.json`
+- `config/system-init-script.json`
+- `config/script-templates.json`
+
+Damit kann der komplette Ordner inklusive Service-Dateien auf einen anderen Rechner kopiert werden.
+
+Optional kann ein anderes Config-Verzeichnis gesetzt werden:
+
+```bat
+java -Dopcua.config.dir=C:\OPCUAClient\config -jar opcua-gui-1.0.0.jar --service
+```
+
+Für verschlüsselte Configs kann im Service zusätzlich ein Passwort übergeben werden, falls es nicht in den Settings hinterlegt werden soll:
+
+```bat
+java -Dopcua.config.password=MeinConfigPasswort -jar opcua-gui-1.0.0.jar --service
+```
diff --git a/windows-service/build-exe.bat b/windows-service/build-exe.bat
new file mode 100644
index 0000000..d3401b1
--- /dev/null
+++ b/windows-service/build-exe.bat
@@ -0,0 +1,7 @@
+@echo off
+setlocal
+cd /d "%~dp0\.."
+call mvn -Pwindows-exe clean package -DskipTests
+if errorlevel 1 exit /b %errorlevel%
+echo.
+echo EXE erstellt: target\opcua-gui.exe
diff --git a/windows-service/install-service.bat b/windows-service/install-service.bat
new file mode 100644
index 0000000..51af232
--- /dev/null
+++ b/windows-service/install-service.bat
@@ -0,0 +1,22 @@
+@echo off
+setlocal
+cd /d "%~dp0"
+
+if not exist "opcua-gui-1.0.0.jar" (
+  echo ERROR: opcua-gui-1.0.0.jar fehlt. Bitte die gebaute JAR in diesen Ordner kopieren.
+  exit /b 1
+)
+
+if exist "OPCUAClientService.exe" goto install
+if exist "WinSW-x64.exe" (
+  copy /Y "WinSW-x64.exe" "OPCUAClientService.exe" >nul
+) else (
+  echo ERROR: WinSW-x64.exe fehlt.
+  echo Lade WinSW-x64.exe von https://github.com/winsw/winsw/releases herunter und lege sie in diesen Ordner.
+  exit /b 1
+)
+
+:install
+"%~dp0OPCUAClientService.exe" install
+if errorlevel 1 exit /b %errorlevel%
+echo Service installiert.
diff --git a/windows-service/prepare-service-folder.bat b/windows-service/prepare-service-folder.bat
new file mode 100644
index 0000000..308f3df
--- /dev/null
+++ b/windows-service/prepare-service-folder.bat
@@ -0,0 +1,7 @@
+@echo off
+setlocal
+cd /d "%~dp0\.."
+call mvn clean package -DskipTests
+if errorlevel 1 exit /b %errorlevel%
+copy /Y "target\opcua-gui-1.0.0.jar" "windows-service\opcua-gui-1.0.0.jar" >nul
+echo Service-Ordner vorbereitet. Jetzt WinSW-x64.exe in windows-service ablegen und install-service.bat als Administrator starten.
diff --git a/windows-service/start-service.bat b/windows-service/start-service.bat
new file mode 100644
index 0000000..f0dc128
--- /dev/null
+++ b/windows-service/start-service.bat
@@ -0,0 +1,4 @@
+@echo off
+setlocal
+cd /d "%~dp0"
+"%~dp0OPCUAClientService.exe" start
diff --git a/windows-service/status-service.bat b/windows-service/status-service.bat
new file mode 100644
index 0000000..185b006
--- /dev/null
+++ b/windows-service/status-service.bat
@@ -0,0 +1,4 @@
+@echo off
+setlocal
+cd /d "%~dp0"
+"%~dp0OPCUAClientService.exe" status
diff --git a/windows-service/stop-service.bat b/windows-service/stop-service.bat
new file mode 100644
index 0000000..0d79218
--- /dev/null
+++ b/windows-service/stop-service.bat
@@ -0,0 +1,4 @@
+@echo off
+setlocal
+cd /d "%~dp0"
+"%~dp0OPCUAClientService.exe" stop
diff --git a/windows-service/uninstall-service.bat b/windows-service/uninstall-service.bat
new file mode 100644
index 0000000..8598f45
--- /dev/null
+++ b/windows-service/uninstall-service.bat
@@ -0,0 +1,9 @@
+@echo off
+setlocal
+cd /d "%~dp0"
+if not exist "OPCUAClientService.exe" (
+  echo ERROR: OPCUAClientService.exe fehlt.
+  exit /b 1
+)
+"%~dp0OPCUAClientService.exe" stop
+"%~dp0OPCUAClientService.exe" uninstall