diff --git a/changelog.md b/changelog.md
index c8b4b3b..746c0ba 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,14 @@
 # Changelog
 
+## 2026-01-09 - 0.4.0 - feat(displays)
+add display detection and management (sway) with daemon APIs and UI controls
+
+- Introduce DisplayInfo type in system-info.ts
+- Add ProcessManager methods: getDisplays, setDisplayEnabled, setKioskDisplay (invoke swaymsg via runuser)
+- Add daemon methods to expose getDisplays, setDisplayEnabled and setKioskDisplay with runtime/Wayland context and status checks
+- Add UI server endpoints: GET /api/displays and POST /api/displays/{name}/(enable|disable|primary) and frontend UI to list and control displays (polling + buttons)
+- Bump VERSION and package.json to 0.3.9
+
 ## 2026-01-09 - 0.3.8 - fix(ci(release-workflow))
 use npx tsx to run release-upload.ts in the Gitea release workflow instead of installing tsx globally
 
diff --git a/ecoos_daemon/ts/daemon/index.ts b/ecoos_daemon/ts/daemon/index.ts
index e0a31aa..93e0498 100644
--- a/ecoos_daemon/ts/daemon/index.ts
+++ b/ecoos_daemon/ts/daemon/index.ts
@@ -5,7 +5,7 @@
  */
 
 import { ProcessManager } from './process-manager.ts';
-import { SystemInfo } from './system-info.ts';
+import { SystemInfo, type DisplayInfo } from './system-info.ts';
 import { Updater } from './updater.ts';
 import { UIServer } from '../ui/server.ts';
 import { runCommand } from '../utils/command.ts';
@@ -147,6 +147,47 @@ export class EcoDaemon {
     return this.updater.upgradeToVersion(version);
   }
 
+  async getDisplays(): Promise<DisplayInfo[]> {
+    if (this.swayStatus.state !== 'running') {
+      return [];
+    }
+    const uid = await this.getUserUid();
+    return this.processManager.getDisplays({
+      runtimeDir: `/run/user/${uid}`,
+      waylandDisplay: this.config.waylandDisplay,
+    });
+  }
+
+  async setDisplayEnabled(name: string, enabled: boolean): Promise<{ success: boolean; message: string }> {
+    if (this.swayStatus.state !== 'running') {
+      return { success: false, message: 'Sway is not running' };
+    }
+    this.log(`${enabled ? 'Enabling' : 'Disabling'} display ${name}`);
+    const uid = await this.getUserUid();
+    const result = await this.processManager.setDisplayEnabled(
+      { runtimeDir: `/run/user/${uid}`, waylandDisplay: this.config.waylandDisplay },
+      name,
+      enabled
+    );
+    return { success: result, message: result ? `Display ${name} ${enabled ? 'enabled' : 'disabled'}` : 'Failed' };
+  }
+
+  async setKioskDisplay(name: string): Promise<{ success: boolean; message: string }> {
+    if (this.swayStatus.state !== 'running') {
+      return { success: false, message: 'Sway is not running' };
+    }
+    if (this.chromiumStatus.state !== 'running') {
+      return { success: false, message: 'Chromium is not running' };
+    }
+    this.log(`Moving kiosk to display ${name}`);
+    const uid = await this.getUserUid();
+    const result = await this.processManager.setKioskDisplay(
+      { runtimeDir: `/run/user/${uid}`, waylandDisplay: this.config.waylandDisplay },
+      name
+    );
+    return { success: result, message: result ? `Kiosk moved to ${name}` : 'Failed' };
+  }
+
   async start(): Promise<void> {
     this.log('EcoOS Daemon starting...');
 
diff --git a/ecoos_daemon/ts/daemon/process-manager.ts b/ecoos_daemon/ts/daemon/process-manager.ts
index ba9b9bc..729d71c 100644
--- a/ecoos_daemon/ts/daemon/process-manager.ts
+++ b/ecoos_daemon/ts/daemon/process-manager.ts
@@ -5,6 +5,7 @@
  */
 
 import { runCommand } from '../utils/command.ts';
+import type { DisplayInfo } from './system-info.ts';
 
 export interface SwayConfig {
   runtimeDir: string;
@@ -306,6 +307,95 @@ for_window [app_id="chromium-browser"] fullscreen enable
     }
   }
 
+  /**
+   * Get connected displays via swaymsg
+   */
+  async getDisplays(config: { runtimeDir: string; waylandDisplay: string }): Promise<DisplayInfo[]> {
+    const env: Record<string, string> = {
+      XDG_RUNTIME_DIR: config.runtimeDir,
+      WAYLAND_DISPLAY: config.waylandDisplay,
+    };
+
+    const envString = Object.entries(env)
+      .map(([k, v]) => `${k}=${v}`)
+      .join(' ');
+
+    const cmd = new Deno.Command('runuser', {
+      args: ['-u', this.user, '--', 'sh', '-c', `${envString} swaymsg -t get_outputs`],
+      stdout: 'piped',
+      stderr: 'piped',
+    });
+
+    try {
+      const result = await cmd.output();
+      if (!result.success) {
+        console.error('[displays] Failed to get outputs');
+        return [];
+      }
+
+      const outputs = JSON.parse(new TextDecoder().decode(result.stdout));
+      return outputs.map((output: {
+        name: string;
+        make: string;
+        model: string;
+        serial: string;
+        active: boolean;
+        current_mode?: { width: number; height: number; refresh: number };
+        focused: boolean;
+      }) => ({
+        name: output.name,
+        make: output.make || 'Unknown',
+        model: output.model || 'Unknown',
+        serial: output.serial || '',
+        active: output.active,
+        width: output.current_mode?.width || 0,
+        height: output.current_mode?.height || 0,
+        refreshRate: Math.round((output.current_mode?.refresh || 0) / 1000),
+        isPrimary: output.focused,
+      }));
+    } catch (error) {
+      console.error(`[displays] Error: ${error}`);
+      return [];
+    }
+  }
+
+  /**
+   * Enable or disable a display
+   */
+  async setDisplayEnabled(
+    config: { runtimeDir: string; waylandDisplay: string },
+    name: string,
+    enabled: boolean
+  ): Promise<boolean> {
+    const command = `output ${name} ${enabled ? 'enable' : 'disable'}`;
+    console.log(`[displays] ${command}`);
+    return this.swaymsg(config, command);
+  }
+
+  /**
+   * Move the kiosk browser to a specific display
+   */
+  async setKioskDisplay(
+    config: { runtimeDir: string; waylandDisplay: string },
+    name: string
+  ): Promise<boolean> {
+    console.log(`[displays] Setting primary display to ${name}`);
+
+    // Focus the chromium window and move it to the target output
+    const commands = [
+      `[app_id="chromium-browser"] focus`,
+      `move container to output ${name}`,
+      `focus output ${name}`,
+      `[app_id="chromium-browser"] fullscreen enable`,
+    ];
+
+    for (const cmd of commands) {
+      await this.swaymsg(config, cmd);
+    }
+
+    return true;
+  }
+
   private async pipeOutput(
     process: Deno.ChildProcess,
     name: string
diff --git a/ecoos_daemon/ts/daemon/system-info.ts b/ecoos_daemon/ts/daemon/system-info.ts
index 7990548..624c094 100644
--- a/ecoos_daemon/ts/daemon/system-info.ts
+++ b/ecoos_daemon/ts/daemon/system-info.ts
@@ -52,6 +52,18 @@ export interface AudioDevice {
   isDefault: boolean;
 }
 
+export interface DisplayInfo {
+  name: string;           // e.g., "DP-1", "HDMI-A-1", "HEADLESS-1"
+  make: string;           // Manufacturer
+  model: string;          // Model name
+  serial: string;         // Serial number
+  active: boolean;        // Currently enabled
+  width: number;          // Resolution width
+  height: number;         // Resolution height
+  refreshRate: number;    // Hz
+  isPrimary: boolean;     // Has the focused window (kiosk)
+}
+
 export interface SystemInfoData {
   hostname: string;
   cpu: CpuInfo;
diff --git a/ecoos_daemon/ts/ui/server.ts b/ecoos_daemon/ts/ui/server.ts
index 0219324..95ded38 100644
--- a/ecoos_daemon/ts/ui/server.ts
+++ b/ecoos_daemon/ts/ui/server.ts
@@ -129,6 +129,28 @@ export class UIServer {
       }
     }
 
+    if (path === '/api/displays') {
+      const displays = await this.daemon.getDisplays();
+      return new Response(JSON.stringify({ displays }), { headers });
+    }
+
+    // Display control endpoints: /api/displays/{name}/{action}
+    const displayMatch = path.match(/^\/api\/displays\/([^/]+)\/(enable|disable|primary)$/);
+    if (displayMatch && req.method === 'POST') {
+      const name = decodeURIComponent(displayMatch[1]);
+      const action = displayMatch[2];
+
+      let result;
+      if (action === 'enable') {
+        result = await this.daemon.setDisplayEnabled(name, true);
+      } else if (action === 'disable') {
+        result = await this.daemon.setDisplayEnabled(name, false);
+      } else if (action === 'primary') {
+        result = await this.daemon.setKioskDisplay(name);
+      }
+      return new Response(JSON.stringify(result), { headers });
+    }
+
     return new Response(JSON.stringify({ error: 'Not Found' }), {
       status: 404,
       headers,
@@ -384,6 +406,10 @@ export class UIServer {
           Check for Updates
         </button>
       </div>
+      <div class="card">
+        <h2>Displays</h2>
+        <div id="displays-list"></div>
+      </div>
       <div class="card">
         <h2>Input Devices</h2>
         <div id="input-devices-list"></div>
@@ -698,6 +724,64 @@ export class UIServer {
     fetchUpdates();
     setInterval(fetchUpdates, 60000); // Check every minute
 
+    // Display management
+    function updateDisplaysUI(data) {
+      const list = document.getElementById('displays-list');
+      if (!data.displays || data.displays.length === 0) {
+        list.innerHTML = '<div style="color: var(--text-dim);">No displays detected</div>';
+        return;
+      }
+      list.innerHTML = data.displays.map(d =>
+        '<div class="device-item" style="flex-wrap: wrap; gap: 8px;">' +
+          '<div style="flex: 1; min-width: 150px;">' +
+            '<div class="device-name">' + d.name + '</div>' +
+            '<div style="font-size: 11px; color: var(--text-dim);">' +
+              d.width + 'x' + d.height + ' @ ' + d.refreshRate + 'Hz' +
+              (d.make !== 'Unknown' ? ' • ' + d.make : '') +
+            '</div>' +
+          '</div>' +
+          '<div style="display: flex; gap: 4px;">' +
+            (d.isPrimary
+              ? '<span class="device-default">Primary</span>'
+              : '<button class="btn btn-primary" style="padding: 2px 8px; margin: 0; font-size: 11px;" onclick="setKioskDisplay(\\'' + d.name + '\\')">Set Primary</button>') +
+            '<button class="btn ' + (d.active ? 'btn-danger' : 'btn-primary') + '" style="padding: 2px 8px; margin: 0; font-size: 11px;" onclick="toggleDisplay(\\'' + d.name + '\\', ' + !d.active + ')">' +
+              (d.active ? 'Disable' : 'Enable') +
+            '</button>' +
+          '</div>' +
+        '</div>'
+      ).join('');
+    }
+
+    function fetchDisplays() {
+      fetch('/api/displays')
+        .then(r => r.json())
+        .then(updateDisplaysUI)
+        .catch(err => console.error('Failed to fetch displays:', err));
+    }
+
+    function toggleDisplay(name, enable) {
+      fetch('/api/displays/' + encodeURIComponent(name) + '/' + (enable ? 'enable' : 'disable'), { method: 'POST' })
+        .then(r => r.json())
+        .then(result => {
+          if (!result.success) alert(result.message);
+          fetchDisplays();
+        })
+        .catch(err => alert('Error: ' + err));
+    }
+
+    function setKioskDisplay(name) {
+      fetch('/api/displays/' + encodeURIComponent(name) + '/primary', { method: 'POST' })
+        .then(r => r.json())
+        .then(result => {
+          if (!result.success) alert(result.message);
+          fetchDisplays();
+        })
+        .catch(err => alert('Error: ' + err));
+    }
+
+    fetchDisplays();
+    setInterval(fetchDisplays, 5000); // Refresh every 5 seconds
+
     // Initial fetch
     fetch('/api/status')
       .then(r => r.json())
diff --git a/ecoos_daemon/ts/version.ts b/ecoos_daemon/ts/version.ts
index 685b359..0b28a75 100644
--- a/ecoos_daemon/ts/version.ts
+++ b/ecoos_daemon/ts/version.ts
@@ -1 +1 @@
-export const VERSION = "0.3.6";
+export const VERSION = "0.3.9";
diff --git a/isobuild/config/includes.chroot/opt/eco/bin/eco-daemon b/isobuild/config/includes.chroot/opt/eco/bin/eco-daemon
index f170848..64d4bd1 100755
Binary files a/isobuild/config/includes.chroot/opt/eco/bin/eco-daemon and b/isobuild/config/includes.chroot/opt/eco/bin/eco-daemon differ
diff --git a/package.json b/package.json
index c0cb90a..d959c3f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ecobridge/eco-os",
-  "version": "0.3.8",
+  "version": "0.3.9",
   "private": true,
   "scripts": {
     "build": "[ -z \"$CI\" ] && npm version patch --no-git-tag-version || true && node -e \"const v=require('./package.json').version; require('fs').writeFileSync('ecoos_daemon/ts/version.ts', 'export const VERSION = \\\"'+v+'\\\";\\n');\" && pnpm run daemon:bundle && cp ecoos_daemon/bundle/eco-daemon isobuild/config/includes.chroot/opt/eco/bin/ && mkdir -p .nogit/iso && docker build --no-cache -t ecoos-builder -f isobuild/Dockerfile . && docker run --privileged --name ecoos-build ecoos-builder && docker cp ecoos-build:/output/ecoos.iso .nogit/iso/ecoos.iso && docker rm ecoos-build",