What causes Error: listen EADDRINUSE: address already in use :::3000?

Another application or previous server instance is occupying port 3000; A background service or development tool is holding the port open

How do I fix Error: listen EADDRINUSE: address already in use :::3000?

Check which process is using the port; Stop the process using the port; Use a different port in your code

Last checked 2026-10-17 · 3 fixes · reviewed answer

TL;DRYour server code tried to start listening on port 3000 but another program is already using that port.

Another application or previous server instance is occupying port 3000most likely
A background service or development tool is holding the port openpossible

Safest first: SafeChanges settingsDangerous

Check which process is using the portSafe

Run a command to list active connections on port 3000 and note any process ID shown.
```
lsof -i :3000 || netstat -ano | findstr :3000
```
Stop the process using the portChanges settings

Terminate the process ID that is using port 3000.
```
kill <process-id>
```
⚠ This stops whatever program is currently using the port.
Use a different port in your codeChanges settings

Edit the line where your server listens and change 3000 to another number such as 3001, then restart the app.

Restarting the computer will release the port if the conflict persists after the steps above.

Consult a technician if you are unsure how to identify or safely stop processes on your system.