diff --git a/docker-compose.yml b/docker-compose.yml
index d7f6363..4687484 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -5,4 +5,12 @@ services:
     build: .
     ports:
       - "7481:3000"
+    restart: unless-stopped
+
+  sync-service:
+    build: ./sync-server
+    ports:
+      - "7482:3001"
+    volumes:
+      - ./data:/app/data
     restart: unless-stopped
\ No newline at end of file
diff --git a/index.html b/index.html
index 049df05..30a9121 100644
--- a/index.html
+++ b/index.html
@@ -139,6 +139,9 @@
         const { useState, useEffect, useRef, useMemo, useCallback } = React;
 
         const API_BASE = "https://music-dl.sayqz.com";
+        // Use relative path for sync service, assuming Nginx proxy is configured to forward /api/kv to the sync service
+        const SYNC_API_BASE = "/api";
+        
         const SOURCES = [
             { id: 'netease', name: '网易云' },
             { id: 'kuwo', name: '酷我' },
@@ -245,6 +248,34 @@
             }
         };
 
+        // --- Sync Service ---
+        const syncService = {
+            get: async (key, token) => {
+                if (!token) return null;
+                try {
+                    const res = await fetch(`${SYNC_API_BASE}/kv/${key}?token=${encodeURIComponent(token)}`);
+                    if (res.ok) {
+                        return await res.json();
+                    }
+                } catch (e) {
+                    console.error("Sync get failed", e);
+                }
+                return null;
+            },
+            set: async (key, data, token) => {
+                if (!token) return;
+                try {
+                    await fetch(`${SYNC_API_BASE}/kv/${key}?token=${encodeURIComponent(token)}`, {
+                        method: 'POST',
+                        headers: { 'Content-Type': 'application/json' },
+                        body: JSON.stringify(data)
+                    });
+                } catch (e) {
+                    console.error("Sync set failed", e);
+                }
+            }
+        };
+
         // --- Components ---
 
         const Icon = ({ name, size = "", className = "", onClick }) => (
@@ -319,7 +350,7 @@
             </div>
         );
 
-        const SideDrawer = ({ isOpen, onClose, view, setView, quality, setQuality, onClearCache }) => {
+        const SideDrawer = ({ isOpen, onClose, view, setView, quality, setQuality, onClearCache, syncToken, setSyncToken, onSyncNow }) => {
             if (!isOpen) return null;
 
             return (
@@ -366,6 +397,26 @@
                                 </select>
                             </div>
 
+                            <div className="px-4 py-2">
+                                <label className="block text-sm text-gray-300 mb-2">云同步密钥</label>
+                                <div className="flex gap-2">
+                                    <input
+                                        type="text"
+                                        value={syncToken}
+                                        onChange={(e) => setSyncToken(e.target.value)}
+                                        placeholder="输入任意密钥以同步"
+                                        className="bg-white/10 border border-white/20 rounded-lg px-3 py-2 text-sm text-white w-full focus:outline-none focus:border-primary"
+                                    />
+                                    <button
+                                        onClick={onSyncNow}
+                                        className="bg-primary text-black px-3 py-2 rounded-lg text-sm font-bold whitespace-nowrap"
+                                    >
+                                        同步
+                                    </button>
+                                </div>
+                                <p className="text-xs text-gray-500 mt-1">使用相同的密钥在多端同步收藏列表</p>
+                            </div>
+
                              <div className="px-4 py-2 mt-2">
                                 <button
                                     onClick={() => {
@@ -698,6 +749,7 @@
             const [volume, setVolume] = useState(1);
             const [favorites, setFavorites] = useState(() => JSON.parse(localStorage.getItem('th_favorites')) || []);
             const [quality, setQuality] = useState(() => localStorage.getItem('th_quality') || '320k');
+            const [syncToken, setSyncToken] = useState(() => localStorage.getItem('th_sync_token') || '');
             
             // UI State
             const [showFullPlayer, setShowFullPlayer] = useState(false);
@@ -716,8 +768,40 @@
             
             useEffect(() => { localStorage.setItem('th_playlist', JSON.stringify(playlist)); }, [playlist]);
             useEffect(() => { localStorage.setItem('th_current', JSON.stringify(currentSong)); }, [currentSong]);
-            useEffect(() => { localStorage.setItem('th_favorites', JSON.stringify(favorites)); }, [favorites]);
+            useEffect(() => {
+                localStorage.setItem('th_favorites', JSON.stringify(favorites));
+                // Auto sync to cloud if token exists
+                if (syncToken && favorites.length > 0) {
+                    // Debounce could be added here, but for simplicity we just sync
+                    syncService.set('favorites', favorites, syncToken);
+                }
+            }, [favorites, syncToken]);
             useEffect(() => { localStorage.setItem('th_quality', quality); }, [quality]);
+            useEffect(() => { localStorage.setItem('th_sync_token', syncToken); }, [syncToken]);
+
+            // Initial Sync
+            useEffect(() => {
+                if (syncToken) {
+                    handleSync();
+                }
+            }, []); // Run once on mount if token exists
+
+            const handleSync = async () => {
+                if (!syncToken) return;
+                const cloudFavorites = await syncService.get('favorites', syncToken);
+                if (cloudFavorites && Array.isArray(cloudFavorites)) {
+                    // Merge strategy: Combine unique songs by ID
+                    setFavorites(prev => {
+                        const combined = [...prev];
+                        cloudFavorites.forEach(cloudSong => {
+                            if (!combined.find(s => s.id === cloudSong.id)) {
+                                combined.push(cloudSong);
+                            }
+                        });
+                        return combined;
+                    });
+                }
+            };
 
             useEffect(() => {
                 if (currentSong) {
diff --git a/nginx.conf.example b/nginx.conf.example
new file mode 100644
index 0000000..fec9438
--- /dev/null
+++ b/nginx.conf.example
@@ -0,0 +1,27 @@
+server {
+    listen 80;
+    server_name your-domain.com;
+
+    # 前端静态资源 (Music Canvas)
+    location / {
+        proxy_pass http://127.0.0.1:7481;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+    }
+
+    # 同步服务 API 代理
+    # 将 /api/kv/... 转发到 sync-service 的 7482 端口
+    # 注意：这里去掉了 /api 前缀，因为 sync-service 直接监听 /kv
+    location /api/ {
+        proxy_pass http://127.0.0.1:7482/;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        
+        # 允许跨域 (如果前端和后端不在同一个域)
+        add_header 'Access-Control-Allow-Origin' '*';
+        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
+        add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
+    }
+}
\ No newline at end of file
diff --git a/sync-server/Dockerfile b/sync-server/Dockerfile
new file mode 100644
index 0000000..1f6dfc8
--- /dev/null
+++ b/sync-server/Dockerfile
@@ -0,0 +1,9 @@
+FROM node:18-alpine
+
+WORKDIR /app
+
+COPY server.js .
+
+EXPOSE 3001
+
+CMD ["node", "server.js"]
\ No newline at end of file
diff --git a/sync-server/server.js b/sync-server/server.js
new file mode 100644
index 0000000..536c24b
--- /dev/null
+++ b/sync-server/server.js
@@ -0,0 +1,85 @@
+const http = require('http');
+const fs = require('fs');
+const path = require('path');
+const url = require('url');
+
+const DATA_DIR = process.env.DATA_DIR || './data';
+const PORT = process.env.PORT || 3001;
+
+// Ensure data directory exists
+if (!fs.existsSync(DATA_DIR)) {
+    fs.mkdirSync(DATA_DIR, { recursive: true });
+}
+
+const server = http.createServer((req, res) => {
+    // CORS headers
+    res.setHeader('Access-Control-Allow-Origin', '*');
+    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
+    res.setHeader('Access-Control-Allow-Headers', 'Content-Type');
+
+    if (req.method === 'OPTIONS') {
+        res.writeHead(204);
+        res.end();
+        return;
+    }
+
+    const parsedUrl = url.parse(req.url, true);
+    const pathname = parsedUrl.pathname;
+    
+    // Path format: /kv/:key?token=...
+    const match = pathname.match(/^\/kv\/([a-zA-Z0-9_-]+)$/);
+    
+    if (!match) {
+        res.writeHead(404, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ error: 'Invalid path' }));
+        return;
+    }
+
+    const key = match[1];
+    const token = parsedUrl.query.token;
+
+    if (!token) {
+        res.writeHead(401, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ error: 'Token required' }));
+        return;
+    }
+
+    // Simple file-based storage: data/{token}_{key}.json
+    // Using token in filename ensures isolation between users
+    const safeToken = token.replace(/[^a-zA-Z0-9]/g, '');
+    const filePath = path.join(DATA_DIR, `${safeToken}_${key}.json`);
+
+    if (req.method === 'GET') {
+        if (fs.existsSync(filePath)) {
+            const data = fs.readFileSync(filePath);
+            res.writeHead(200, { 'Content-Type': 'application/json' });
+            res.end(data);
+        } else {
+            res.writeHead(200, { 'Content-Type': 'application/json' });
+            res.end(JSON.stringify(null)); // Key not found returns null
+        }
+    } else if (req.method === 'POST') {
+        let body = '';
+        req.on('data', chunk => body += chunk.toString());
+        req.on('end', () => {
+            try {
+                // Validate JSON
+                JSON.parse(body);
+                fs.writeFileSync(filePath, body);
+                res.writeHead(200, { 'Content-Type': 'application/json' });
+                res.end(JSON.stringify({ success: true }));
+            } catch (e) {
+                res.writeHead(400, { 'Content-Type': 'application/json' });
+                res.end(JSON.stringify({ error: 'Invalid JSON' }));
+            }
+        });
+    } else {
+        res.writeHead(405);
+        res.end();
+    }
+});
+
+server.listen(PORT, () => {
+    console.log(`Sync Server running on port ${PORT}`);
+    console.log(`Data directory: ${DATA_DIR}`);
+});
\ No newline at end of file