How to Kill Port 3000 on Mac (macOS)

Quick Fix: One Command with portrm

The fastest way to kill port 3000 on a Mac is with portrm. It finds the process, identifies the service, checks if it is safe to kill, and frees the port:

$ ptrm fix 3000

  Port 3000 in use
  Next.js dev server (PID 48291) - node
  SAFE - development server

  Fix port 3000? [Y/n] Y
  Killed PID 48291
  Port 3000 is now free

Install with brew install abhishekayu/tap/portrm or npm install -g portrm.

Method 1: lsof + kill

The standard macOS approach uses lsof to find the process and kill to terminate it:

# Step 1: Find what is using port 3000
$ lsof -i :3000
COMMAND   PID  USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
node    48291  dev    23u  IPv6 0x...  0t0      TCP *:hbci (LISTEN)

# Step 2: Kill the process by PID
$ kill -9 48291

The -i :3000 flag tells lsof to show processes listening on port 3000. The PID column gives you the process ID to kill.

One-liner version

Combine both steps into a single command:

$ kill -9 $(lsof -ti :3000)

The -t flag makes lsof output only the PID, which gets passed directly to kill.

Method 2: Activity Monitor

If you prefer a GUI approach:

1. Open Activity Monitor (Spotlight: Cmd+Space, type "Activity Monitor")
2. Click the Network tab
3. Use the search bar to find the process name (e.g., "node")
4. Select the process and click the X button in the toolbar
5. Choose Force Quit

This works but does not tell you which port a process is bound to. Use lsof or ptrm first to identify the right process.

Method 3: Using fuser

Some macOS setups have fuser available:

$ fuser 3000/tcp
3000/tcp:  48291
$ kill -9 48291

What Typically Uses Port 3000 on Mac?

Prevent Port 3000 Conflicts on Mac

Instead of killing processes every time, configure your project to handle port conflicts automatically:

# Create a .ptrm.toml in your project root
$ ptrm init

# Check if port 3000 is free before starting your server
$ ptrm preflight 3000 && npm run dev

# Or auto-fix conflicts before starting
$ ptrm fix 3000 -y && npm run dev

Troubleshooting

lsof shows nothing but port 3000 is still in use

The process might be in a TIME_WAIT state. Wait 30-60 seconds for the OS to release it, or use:

$ ptrm scan | grep 3000

portrm detects TIME_WAIT sockets and shows their remaining timeout.

Permission denied when killing the process

The process may be running as root. Prefix with sudo:

$ sudo kill -9 $(lsof -ti :3000)
# Or with portrm
$ sudo ptrm fix 3000