What’s running on port 8787 on my Mac?

Check what’s on port 8787

lsof -nP -iTCP:8787 -sTCP:LISTEN
ps -o pid,etime,command -p <PID>

You’ll usually see two processes: node running Wrangler, and workerd, the Workers runtime it spawns. Either way, the working folder tells you which Worker:

lsof -a -p <PID> -d cwd -Fn | tail -1

With Stat Space: statspace port 8787.

Free it

Press x or Ctrl-C in the Wrangler terminal. From elsewhere, kill the node process; it takes workerd down with it. If workerd survives on its own (it can after a crash), kill it too:

pkill -f workerd

Only do that if no other Wrangler session should be running.

Change the port

One-off:

npx wrangler dev --port 8790

Permanently, in wrangler.jsonc:

{
  "dev": {
    "port": 8790
  }
}

Or in wrangler.toml:

[dev]
port = 8790

If 8787 is busy, current Wrangler versions pick a free port on their own and print it, so check the terminal output for the URL. For Pages projects, the same --port flag works on wrangler pages dev.

Who can reach it

wrangler dev binds to localhost. --ip 0.0.0.0 (or "ip": "0.0.0.0" under dev) makes it reachable from your network. Your local Worker sees your .dev.vars secrets and local D1, KV and R2 data, so an exposed dev Worker can leak both. Keep the default unless you’re testing from a phone. See dev server exposed to the network.

Seeing it live

Stat Space lists 8787 with the Worker’s project folder, the launcher that started it and its uptime, next to the Vite or Next.js frontend it usually pairs with.