diff --git a/src/tracker/api/messages.py b/src/tracker/api/messages.py
index cd04854..52ee1d3 100644
--- a/src/tracker/api/messages.py
+++ b/src/tracker/api/messages.py
@@ -120,6 +120,41 @@ async def create_message(req: MessageCreate, db: AsyncSession = Depends(get_db))
         select(Message).where(Message.id == msg.id).options(selectinload(Message.attachments))
     )
     msg = result2.scalar_one()
+
+    # Broadcast via WebSocket
+    from tracker.ws.manager import manager
+    msg_data = {
+        "id": str(msg.id),
+        "chat_id": req.chat_id,
+        "task_id": req.task_id,
+        "author_type": msg.author_type,
+        "author_slug": msg.author_slug,
+        "content": msg.content,
+        "mentions": msg.mentions or [],
+        "created_at": msg.created_at.isoformat(),
+    }
+
+    project_id = None
+    if req.chat_id:
+        chat_result = await db.execute(select(Chat).where(Chat.id == uuid.UUID(req.chat_id)))
+        chat = chat_result.scalar_one_or_none()
+        if chat and chat.project_id:
+            project_id = str(chat.project_id)
+        elif chat and chat.kind == "lobby":
+            await manager.broadcast_all(
+                {"type": "message.new", "data": msg_data},
+                exclude=msg.author_slug,
+            )
+            return _message_out(msg)
+
+    if project_id:
+        await manager.broadcast_message(project_id, msg_data, author_slug=msg.author_slug)
+    else:
+        await manager.broadcast_all(
+            {"type": "message.new", "data": msg_data},
+            exclude=msg.author_slug,
+        )
+
     return _message_out(msg)