hugo server won't start: port already in use

You run hugo server and get:

Error: listen tcp 127.0.0.1:1313: bind: address already in use

Nothing is wrong with the site – another process is already listening on port 1313. It may be an earlier hugo server process.

The quick way out: use another port

hugo server --port 1314

Two processes cannot listen on the same address and port.

Find what’s holding the port

lsof -i :1313

COMMAND   PID  USER   FD   TYPE  DEVICE  SIZE/OFF  NODE NAME
hugo    47118 anders   9u  IPv4  0x...      0t0     TCP localhost:bmc-perf-agent (LISTEN)

If it’s a Hugo process you forgot about, stop it:

kill 47118

Stop every Hugo server at once:

pkill -f "hugo server"

If it isn’t Hugo, look at the COMMAND column before you kill anything – 1313 is Hugo’s default, but other tools use nearby ports.

It says the port is in use, but nothing is listening

Two cases worth knowing about:

• The old process no longer responds. If lsof still shows its Hugo PID, stop that process and restart the server.
• You’re behind a different address. hugo server binds to 127.0.0.1 by default. Something bound to 0.0.0.0:1313 (a container, a VM) occupies the same port from your machine’s point of view.

Reuse the existing server

If the process already serves the same project, open http://localhost:1313/ and use the existing server.

In HugoKit: each site has its own tested port, and HugoKit can attach to an existing server for the same project.