diff --git a/backend/src/ws.ts b/backend/src/ws.ts
index 2a14ad5..ecdf647 100644
--- a/backend/src/ws.ts
+++ b/backend/src/ws.ts
@@ -80,9 +80,11 @@ export function setupWebSocket(app: FastifyInstance) {
       broadcast(ids.filter(id => id !== userId), { type: 'user_online', payload: { userId, online: true } });
     }
 
-    socket.on('message', async (raw: any) => {
+    socket.on('message', async (raw: any, isBinary: boolean) => {
       try {
-        const { type, payload } = JSON.parse(raw.toString());
+        const str = isBinary ? raw.toString('utf8') : raw.toString();
+        console.log('[WS] received:', str.substring(0, 200));
+        const { type, payload } = JSON.parse(str);
 
         if (type === 'typing') {
           const members = await getChatMemberIds(payload.chatId);