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

A previous Node.js process is still running in the background Another application is using the same port Running the server twice without stopping the first instance A zombie process from a crashed server

Error3 Fixes Available

Error: EADDRINUSE — address already in use

Error: listen EADDRINUSE: address already in use :::3000

What does this error mean?

Your Node.js server is trying to listen on a port that's already in use by another process. This commonly happens when a previous server process didn't shut down cleanly.

Common Causes

A previous Node.js process is still running in the background
Another application is using the same port
Running the server twice without stopping the first instance
A zombie process from a crashed server

How to Fix It (3 Solutions)

Kill the process on the port

Find and kill whatever is using the port.

Code

# Mac / Linux — find the process
lsof - ti: 3000 | xargs kill - 9

# Windows(PowerShell)
netstat - ano | findstr : 3000
# Then kill the PID shown
taskkill / PID<PID> / F

Use a different port

Change your server to listen on a different port.

Code

// In your server code
const PORT = process.env.PORT || 3001; // change 3000 to 3001
app.listen(PORT, () => console.log(`Server on port ${PORT}`));

Kill all Node processes

Nuclear option — kill all running Node.js processes.

Code

# Mac/Linux
pkill -f node

# Windows
taskkill /F /IM node.exe

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