Run cron jobs

Cron is a service mode for scheduled work: nightly imports, cleanup jobs, report generation. The container starts on a schedule you set, runs to completion, and takes no HTTP traffic.

Create a cron job

1. Create a web service the usual way — from a Git repository, a container image, or an uploaded archive. Your container should run the job and exit when the work is done.
2. Click the service on the environment canvas to open its drawer and go to the Settings tab.
3. In the Deploy section, turn on Run on a schedule.
4. The console pre-fills a daily schedule (0 0 * * *) — replace it with your own 5-field cron expression, for example 0 2 * * *.
5. Press Deploy on the changes bar (Shift+Enter). Mode changes are staged like any other spec edit.

While you type, the console reads the schedule back in words and shows a countdown to the next run, so a typo is visible before you deploy.

The schedule

A cron expression has five fields: minute, hour, day of month, month, day of week.

A schedule is always required in cron mode — through the API, a cron service without one is rejected.

How runs behave

Once deployed, the service's health shows Scheduled — registered and waiting for its next tick. On each tick, Koo starts your container; the run ends when your process exits.

A cron service takes no HTTP traffic and can never be exposed — it has no public URL. If you switch an exposed service to cron mode, its public networking is turned off.

The replica count doesn't apply in cron mode: each tick starts one run in each of the service's locations, and nothing runs between ticks.

Logs

Each run's output lands in the service's Logs tab, like any other service — see logs.

Use variables and databases

Variables work normally in cron mode, including connection variables — so a cron job can use your database, for example a nightly job that works through rows in Postgres. See connect a database.