Replit realtime

Replit WebSocket Proxy Disconnecting

Your real-time features (chat, live updates, notifications) stop working after a few minutes because WebSocket connections are silently dropped. Users see stale data and must refresh the page to get updates again.

Replit routes WebSocket traffic through a reverse proxy that has idle connection timeouts. If no data is sent over the WebSocket for a period of time, the proxy closes the connection. Your app has no reconnection logic, so the connection stays dead until the user refreshes.

This is especially problematic for apps that use WebSockets for occasional updates (like notifications) rather than constant data streams. The connection sits idle between updates and gets killed by the proxy.

Error Messages You Might See

WebSocket connection to 'wss://...' failed WebSocket is already in CLOSING or CLOSED state Error during WebSocket handshake: Unexpected response code: 502 Connection closed abnormally (code 1006)
WebSocket connection to 'wss://...' failedWebSocket is already in CLOSING or CLOSED stateError during WebSocket handshake: Unexpected response code: 502Connection closed abnormally (code 1006)

Common Causes

  • Proxy idle timeout — Replit's reverse proxy closes WebSocket connections that are idle for too long (typically 60 seconds)
  • No ping/pong heartbeat — the app does not send periodic keep-alive messages to prevent timeout
  • No reconnection logic — when the connection drops, the client does not attempt to reconnect
  • Container sleep — Replit free tier containers sleep after inactivity, killing all connections
  • SSL/TLS handshake issues — WebSocket upgrade fails intermittently through the HTTPS proxy

How to Fix It

  1. Implement ping/pong heartbeat — send a ping message every 30 seconds from the server and respond with pong from the client
  2. Add client-side reconnection — detect disconnection and automatically reconnect with exponential backoff
  3. Use a WebSocket library with built-in reconnection — libraries like socket.io or reconnecting-websocket handle this automatically
  4. Handle connection state in UI — show a "reconnecting" indicator when the WebSocket is disconnected
  5. Use wss:// not ws:// — Replit requires secure WebSocket connections since it serves over HTTPS

Real developers can help you.

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Frequently Asked Questions

How often should I send heartbeat pings?

Every 25-30 seconds is a safe interval. This keeps the connection alive through most proxy timeout configurations without creating excessive traffic.

Should I use WebSocket or socket.io on Replit?

socket.io is recommended because it includes automatic reconnection, heartbeats, and fallback to HTTP long-polling when WebSockets are unavailable.

Do WebSockets work on Replit free tier?

Yes, but the free tier containers sleep after inactivity. When the container sleeps, all WebSocket connections are dropped. Paid deployments stay active.

Related Replit Issues

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