An always-on demo or tool

The scenario

You want a build, a demo, a kiosk, or a small internal tool to keep serving — through a terminal you close, an SSH session that drops, or the occasional crash. A foreground servd dies with its shell. A process manager is heavyweight for "just keep this folder on port 8080."

servd --daemon runs the server detached under a supervisor that keeps a worker alive.

One command

servd --spa=./frontend --proxy=/api/=http://localhost:9000/api/ --port=8080 --daemon

--daemon returns only after the worker is actually listening, so it is safe to script and to put behind a health check:

servd 0.1.0 http daemon started on 0.0.0.0:8080 (supervisor pid 41233, worker pid 41240)
log: /Users/you/Library/Caches/servd/8080/servd.log

Control it per port

Daemons are scoped per user and per port, and the control flags take only --port:

servd --status --port=8080   # running / restarting / failed, PIDs, restart count, log path
servd --stop   --port=8080   # stop it; stopping an absent daemon succeeds quietly

--status exits non-zero when the instance is not running, so it slots straight into scripts and CI gates.

Restart policy

A crashed worker restarts with exponential backoff, up to five consecutive times.
A worker that stays up resets the restart budget.
Once the budget is exhausted the instance is marked failed and holds until you --stop and start again — it will not spin forever.

servd :8080 restarting (restart 2/5, next in 2000ms, last exit: exit status 1)

Logs

Supervisor and worker output go to a per-port log file (path printed by --daemon and --status). Logs rotate at 5 MiB with one backup (servd.log and servd.log.1), so a long-running demo will not fill the disk.

A typical flow

# start a preview that survives crashes and shell logouts
servd --spa=./frontend --port=8080 --daemon

# check on it later
servd --status --port=8080

# stop when done
servd --stop --port=8080

Only one daemon can hold a port at a time; starting a second for the same port reports that one already exists. Add TLS to serve the daemon over HTTPS. See Daemon mode for how the supervisor, lock and control endpoint work.