Error: listen EADDRINUSE: address already in use :::3000
bind: Address already in use
OSError: [Errno 98] Address already in use

Another process is already listening on the port you’re trying to use.

Fix 1: Find and Kill the Process

# Find what's using port 3000
lsof -i :3000          # Mac/Linux
netstat -tlnp | grep 3000  # Linux

# Kill it
kill -9 <PID>

# One-liner: kill whatever is on port 3000
lsof -ti :3000 | xargs kill -9

Fix 2: Use a Different Port

# Node.js
PORT=3001 node app.js

# Python
python manage.py runserver 8001

# Or set in .env
PORT=3001

Fix 3: Previous Process Didn’t Shut Down

# ❌ Ctrl+C didn't fully stop the server
# The process is still running in the background

# Find zombie Node processes
ps aux | grep node
kill -9 <PID>

# Or kill all Node processes
killall node

Fix 4: Docker Port Conflict

# ❌ Container or host already using the port
docker ps  # Check running containers

# Use a different host port
docker run -p 3001:3000 myapp  # Map host 3001 → container 3000

Fix 5: SO_REUSEADDR (Server Restart)

// Node.js — allow immediate port reuse after restart
const server = app.listen(3000);
server.on('error', (e) => {
    if (e.code === 'EADDRINUSE') {
        console.log('Port 3000 in use, retrying...');
        setTimeout(() => server.listen(3000), 1000);
    }
});

# Python
import socket
sock = socket.socket()
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(('', 3000))

Fix 6: Windows

# Find process on port 3000
netstat -ano | findstr :3000

# Kill by PID
taskkill /PID <PID> /F

Related resources

• EADDRINUSE port in use fix
• Node EADDRINUSE fix
• Docker port already in use fix