How to fix npm ERR! code EADDRINUSE npm ERR! errno EADDRINUSE npm ERR! Address already in use in npm

Use the kill-port npm package, which works on all platforms:

npx kill-port 3000

Replace 3000 with your actual port number. You can also kill multiple ports at once:

npx kill-port 3000 5000 8080

This is the easiest and most reliable method.

If you prefer not to use a third-party package, find the process ID (PID) first:

lsof -i :3000

This will show you which process is using port 3000. Look for the PID column, then terminate the process:

kill -9 <PID>

Alternatively, use fuser for a one-command solution:

sudo fuser -k 3000/tcp

Open Command Prompt as Administrator and run:

netstat -ano | findstr :3000

This shows the process using port 3000. Note the PID in the rightmost column, then kill it:

taskkill /PID <PID> /F

Alternatively, kill all Node processes:

taskkill /F /IM node.exe

Note: This will kill ALL Node processes, not just the one using the port.

Always use Ctrl+C to stop Node servers, never use Ctrl+Z. Ctrl+Z suspends the process in the background without actually terminating it.

After killing the process, verify the port is now free:

lsof -i :3000

If nothing is returned, the port is free. Now restart your server:

npm start

If the above steps don't work or the port is being used by another service, configure your app to use a different port:

const port = process.env.PORT || 3001;
app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});

Then start with:

PORT=3001 npm start