Replit
ui
WebSocket Connection Failed on Replit
WebSocket connections fail with network errors or close immediately. Real-time features like chat or notifications don't work.
WebSocket configuration and deployment differences between local and Replit cause issues.
Error Messages You Might See
WebSocket connection to 'ws://...' failed
Could not upgrade to WebSocket
Error: Could not find message broker relay
Common Causes
- WebSocket endpoint not exposed or misconfigured
- CORS not allowing WebSocket upgrade requests
- Proxy/load balancer not forwarding WebSocket protocol
- Client using wrong WebSocket URL (ws instead of wss, or localhost)
- StompBroker not configured for Spring WebSocket
How to Fix It
For Spring WebSocket, use WebSocketConfigurer and registerStompEndpoints(). Enable CORS with allowed origins. Client should use 'wss://' (secure WebSocket) on Replit. Verify endpoint path matches client connection URL. Check browser console for actual error message and upgrade handshake details.
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Get HelpFrequently Asked Questions
Should I use ws:// or wss:// on Replit?
Use wss:// (secure) on production. Client auto-detects based on page protocol
How do I configure Spring WebSocket?
Implement WebSocketConfigurer, register endpoint with registerStompEndpoints()