Connect Local dev

The Local dev connector reads the ports programs listen on and the processes running on your Mac. It sends nothing anywhere, keeps nothing in the Keychain, and never stops or signals a process. One covers the whole Mac.

Add the Local dev connector

1. Open Settings › Connectors, click +, choose Local dev.
2. Connector name: what monitors call it, such as local.
3. Click Add Connector.

Port conflicts on every port (port:any) and Heavy processes above memory:4GB come as recommended monitors, added in one click.

The four kinds

Kind	Alerts when	Example body
Port conflicts (localdev.conflicts)	Two different programs listen on the same port	port:any
Ports in use (localdev.ports)	A program starts listening on a port	program:node
Local server down (localdev.down)	A port stops accepting connections, or an address stops answering 2xx	port:3000
Heavy processes (localdev.heavy)	One of your processes goes above a memory or CPU limit	memory:4GB

Port conflicts

Two different programs on one port: an SSH tunnel on 127.0.0.1:8080 shadowing a dev server on *:8080, or a Docker container and a local Postgres both on 5432. One program on both IPv4 and IPv6 is not a conflict, and neither are a server’s own workers.

port:any watches every port. port:3000, port:3000,5432 or port:3000-3999 narrow it.

Ports in use

A program starts listening on a port. The alert gives its name, pid, address and project folder. Narrow it with port:, or with program:, a program’s name or a glob like program:python*.

Local server down

port:3000 alerts when nothing accepts connections on port 3000 any more. url:http://localhost:3000/health alerts when the address stops answering with a 2xx status, or doesn’t answer at all. Each outage alerts once. Once the server is back, the next outage alerts again.

Heavy processes

memory:4GB alerts when one of your processes uses more than 4 GB, the same number as the Memory column of Activity Monitor. cpu:90% alerts on CPU, measured over one second. Add program: to watch only some programs.

A process alerts once when it crosses the limit, and again only after it came back under. Only your own processes are read, not system daemons.

A watch file

-- name: Dev server down
-- kind: localdev.down
-- connector: local
-- every: 1m

port:3000

Local dev reads TCP ports and processes on this Mac. UDP ports and other machines aren’t covered, and it never acts on a process.

Troubleshooting

• A system process shows no memory or CPU. Only your own processes are readable, so Heavy processes leaves out the ones that run as another user, like system daemons.
• Local server down alerts while the server is up. With url:, anything but a 2xx answer counts as down, a 404 included. Point it at a path that answers 200, or watch the port with port:.

Next: the Local dev connector for what it watches.