How to Kill a Process on Port 3000

Fastest Method (Any OS)

$ npx portrm fix 3000

That is it. Works on macOS, Linux, and Windows. No PID lookup, no platform-specific commands.

If you want to kill and restart your dev server:

$ npx portrm fix 3000 --run "npm run dev"

macOS

Method 1: lsof + kill

# Find the PID
$ lsof -ti :3000
84921

# Kill it
$ kill -9 84921

Method 2: One-liner

$ lsof -ti :3000 | xargs kill -9

Method 3: Using fuser

$ fuser -k 3000/tcp

Linux

Method 1: fuser

$ fuser -k 3000/tcp

Method 2: ss + kill

$ ss -tlnp | grep :3000
LISTEN  0  511  *:3000  *:*  users:(("node",pid=84921,fd=23))

$ kill 84921

Method 3: lsof (if installed)

$ lsof -ti :3000 | xargs kill

Windows

Method 1: Command Prompt

# Find the PID
> netstat -ano | findstr :3000
  TCP  0.0.0.0:3000  0.0.0.0:0  LISTENING  12345

# Kill it
> taskkill /PID 12345 /F

Method 2: PowerShell

PS> Get-NetTCPConnection -LocalPort 3000 | Select-Object OwningProcess
PS> Stop-Process -Id 12345 -Force

Method 3: PowerShell One-liner

PS> Get-NetTCPConnection -LocalPort 3000 | ForEach-Object { Stop-Process -Id $_.OwningProcess -Force }

What Commonly Uses Port 3000?

Automate It in Your Project

Add a pre-script to your package.json so port 3000 is always cleared before starting:

{
  "scripts": {
    "predev": "npx portrm fix 3000 -y",
    "dev": "next dev"
  }
}

Now npm run dev always works on the first try.