Node.js Backend Code Debugging

Job ID: 39007397

Budget: £10 – £20 GBP

My backend code, built on Node.js, is experiencing some bugs and errors .I’m experiencing an issue with my Express backend on Replit. I’m developing a full-stack application using Vite + React for the frontend and an Express server for the backend. My setup is designed so that the Express server listens on the port provided by Replit (via process.env.PORT) on host 0.0.0.0, while my Vite server runs on a different port and proxies API requests to the backend.

However, when I start my Express server, I receive an error such as:

Error: listen EADDRINUSE: address already in use 0.0.0.0:<PORT>
I’ve tried changing the fallback port (e.g., 3000, 5000, 5001, 5002), but each time I get a conflict error indicating that the port is already in use. I suspect there might be a stale process or something else in the Replit environment that is holding the port, preventing my server from starting.

I’ve also attempted to manually kill any Node processes via terminal commands like pkill node, but the issue persists.

Could you please help me diagnose why my Express server is unable to bind to the port provided by Replit and how I can resolve this port conflict?
Related categories: JavaScript Linux NoSQL Couch & Mongo Node.js Express JS