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ERROR EADDRINUSE
EADDRINUSE, Address Already in Use
Node.js Error
The port your application is trying to bind to is already in use by another process.
Root Cause
Another process is already listening on the same port, or a previous instance of your app did not shut down cleanly.
How to Fix
Find and kill the process using the port: lsof -i :PORT (macOS/Linux) or netstat -ano | findstr :PORT (Windows). Or change your app's port.
Quick Summary
EADDRINUSE means the port is already in use. Find the process with lsof -i :PORT and kill it, or change your app's port. Common when a previous dev server did not shut down cleanly.
Key Takeaways
Key Takeaways
- Another process is listening on the same port
- Find the process: lsof -i :3000 (macOS/Linux)
- Kill it: kill -9 <PID>
- Or change your app port: PORT=3001 npm start
Use Cases
When to use it
- Starting a dev server when a previous instance is still running
- Port conflict between two services
Watch out
Common Mistakes
- Not checking if a previous instance is still running before starting a new one
FAQ
EADDRINUSE EADDRINUSE, Address Already in Use, Frequently Asked
How do I find what is using port 3000?
macOS/Linux: lsof -i :3000 or ss -tlnp | grep 3000. Windows: netstat -ano | findstr :3000
Still having issues?
Check your network logs or use our developer tools to inspect headers, decode tokens, or validate your requests.