EADDRINUSE: address already in use :::3000

Error: listen EADDRINUSE: address already in use :::3000 means another program is already using port 3000, so your server cannot start there.

What it means

EADDRINUSE is Node’s short name for “address already in use”. Node says an attempt to bind a server to a local address failed because another server on the same computer already holds that address.

The :::3000 part is an address and a port:

• :: is the IPv6 “any address”. Node listens there when you do not give a host name and IPv6 is available.
• :3000 is the port.

Why it happens

Most of the time it is your own old server:

• A dev server from an earlier run is still alive. This is common when a terminal was closed but node kept running.
• Two projects use the same default port.
• Another program (not Node) uses port 3000.

Only one program can listen on one address and port at a time.

How Devpit fixes it

Devpit has a section for exactly this: Fix Stuck Ports & Apps.

1. Open Devpit and choose Fix Stuck Ports & Apps.
2. Choose Kill a port and type 3000.
3. Devpit shows which process holds the port and asks you to confirm. The default answer is No.
4. After you confirm, it stops the process and waits up to two seconds to check that the port is really free.

You can also choose Busy dev ports. It lists which of the usual dev ports are in use right now: 3000 to 3010, 4200, 5000, 5173, 5174, 8000, 8080, 8081, 8888, 9000 and 19000 to 19006. You can change that list in Settings.

If the process was started by npm, pnpm, yarn or node, Devpit can stop the whole process tree, so the parent does not start a child again.

Devpit will not stop some processes. It refuses PID 0 and 4, programs in the Windows System32 folder (except cmd.exe, powershell.exe and conhost.exe), and Windows services, and it says why. Devpit itself never runs as administrator, so if the process runs as administrator Devpit tells you it needs admin. Then close that program yourself or use an administrator terminal.

The manual fix

Find the process ID (PID) that owns the port. In PowerShell:

Get-NetTCPConnection -LocalPort 3000

The OwningProcess column is the PID. Then look at what it is:

Get-Process -Id 12345

Replace 12345 with your PID. If it is your old dev server, stop it:

Stop-Process -Id 12345

You can do the same in Command Prompt. netstat -ano lists connections with their PID (-a all, -n numbers, -o owning PID). taskkill /pid 12345 ends the process, and /f forces it and /t also ends its child processes:

netstat -ano
taskkill /pid 12345 /t /f

Only force a process you understand. If it is not yours, pick another port instead, for example by setting the PORT environment variable that your framework reads.

Sources

• Node.js: Common system errors (EADDRINUSE)
• Node.js: net.Server listen, default host and the :: address
• Microsoft: Get-NetTCPConnection
• Microsoft: Stop-Process
• Microsoft: netstat
• Microsoft: taskkill