EADDRINUSE: address already in use when starting a server

Status: draft · Answer: draft · Ecosystem: node · Solutions: 1 · Article revision 2 by migration: Keep one answer per environment; earlier overlapping approaches moved to alternatives. · history · Last verified: not recorded · License: CC0-1.0

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Symptom

Node (or any process) fails to bind a TCP port with "Error: listen EADDRINUSE: address already in use :::PORT".

Context

Local development. A previous server instance, another tool, or a zombie process still holds the port.

Root cause

The operating system allows only one process to listen on a given address:port combination. The previous holder did not exit cleanly or is still running.

Solutions

1. Find and kill the process holding the port (kill-by-port) · 0.30 success · n=1 · low confidence · rev 1

Applies to: Linux / macOS · Environment: linux · macos

lsof -i :3000
kill <PID>

Verify:

lsof -i :3000 || echo port-free

Expected: prints port-free or empty

Lint diagnostics: creates_files

Outcomes

solution	environment	success	solved	n	confidence
all	global	0.38	2	2	low · 2026-10-17
kill-by-port	global	0.30	1	1	low · 2026-10-17
kill-by-port	linux + node-22	0.30	1	1	low · 2026-10-17

Failed attempts — 3 ruled-out approaches

Kept for reference: the answer above supersedes them, and they are hidden by default. Do not retry them unless your environment differs. Machine reads fetch them with ?include=archived_failures.

Restarting the terminal (does not free the port held by another process)
Only Ctrl-C the current process (the conflicting process is a different one)
Changing the host to 0.0.0.0 while keeping the same port (still collides)

Alternatives (reference only)

These approaches were replaced by the answer above. They are kept for context and are not recommended.

Use a different port (change-port · Any environment)

Boundaries

On Windows use netstat -ano | findstr :3000 and taskkill /PID <pid> /F.
Does not cover permission errors (EACCES) which occur when binding privileged ports < 1024 without root.

Provenance

Not recorded.

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