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.

Krishna Sai Kuncha Krishna Sai Kuncha Experienced Professional Full stack Developer with 8+ years of experience across react, python, js, ts, golang and react-native. Developed inhouse websearch tooling for AI before websearch was solved : ) Dor Yaloz Dor Yaloz SW engineer with 6+ years of experience, I worked with React/Node/Python did projects with React+Capacitor.js for ios Supabase expert Stanislav Prigodich Stanislav Prigodich 15+ years building iOS and web apps at startups and enterprise companies. I want to use that experience to help builders ship real products - when something breaks, I'm here to fix it. Costea Adrian Costea Adrian Embedded Engineer specilizing in perception systems. Latest project was a adas camera calibration system. Antriksh Narang Antriksh Narang 5 years+ Experienced Dev (Specially in Web Development), can help in python, javascript, react, next.js and full stack web dev technologies. Sage Fulcher Sage Fulcher Hey I'm Sage! Im a Boston area software engineer who grew up in South Florida. Ive worked at a ton of cool places like a telehealth kidney care startup that took part in a billion dollar merger (Cricket health/Interwell health), a boutique design agency where I got to work on a ton of exciting startups including a photography education app, a collegiate Esports league and more (Philosophie), a data analytics as a service startup in Cambridge (MA) as well as at Phillips and MIT Lincoln Lab where I designed and developed novel network security visualizations and analytics. I've been writing code and furiously devoted to using computers to make people’s lives easier for about 17 years. My degree is in making computers make pretty lights and sounds. Outside of work I love hip hop, the Celtics, professional wrestling, magic the gathering, photography, drumming, and guitars (both making and playing them) Milan Surelia Milan Surelia Milan Surelia is a Mobile App Developer with 5+ years of experience crafting scalable, cross-platform apps at 7Span and Meticha. At 7Span, he engineers feature-rich Flutter apps with smooth performance and modern UI. As the Co-Founder of Meticha, he builds open-source tools and developer-focused products that solve real-world problems. Expertise: 💡 Developing cross-platform apps using Flutter, Dart, and Jetpack Compose for Android, iOS, and Web. 🖋️ Sharing insights through technical writing, blogging, and open-source contributions. 🤝 Collaborating closely with designers, PMs, and developers to build seamless mobile experiences. Notable Achievements: 🎯 Revamped the Vepaar app into Vepaar Store & CRM with a 2x performance boost and smoother UX. 🚀 Launched Compose101 — a Jetpack Compose starter kit to speed up Android development. 🌟 Open source contributions on Github & StackOverflow for Flutter & Dart 🎖️ Worked on improving app performance and user experience with smart solutions. Milan is always happy to connect, work on new ideas, and explore the latest in technology. Matthew Butler Matthew Butler Systems Development Engineer @ Amazon Web Services MFox MFox Full-stack professional senior engineer (15+years). Extensive experience in software development, qa, and IP networking. Jared Hasson Jared Hasson Full time lead founding dev at a cyber security saas startup, with 10 yoe and a bachelor's in CS. Building & debugging software products is what I've spent my time on for forever

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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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