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A cron job runs a command on a schedule inside your app’s running container. It has your app’s code, dependencies and environment variables, so a job can be as simple as running one of your own scripts.

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Plan limits

The Pro limit counts every job you have created, across all of your apps. See Plans.

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Create a job

1

Open Cron Jobs

Open your app and go to the Cron Jobs tab. Click Add cron job.
2

Enter a name and command

Give the job a name and type the Command to run. It runs with sh -c inside the container, from the container’s working directory.
3

Choose a schedule

Pick a preset or type a standard five-field cron expression. Expressions with seconds are not accepted.
4

Create it

Click Create Job. Symplax installs the schedule on your server.
The presets are:
Schedules run on your server’s clock. Check your server’s time zone before choosing a time of day.

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How jobs run

Symplax writes each job into the cron daemon on your server. When it fires, it runs your command inside the app’s container with docker exec, then reports the result back to Symplax.
  • The job always runs in the current container. After a deploy, it runs against the new version with no changes from you.
  • If the container is not running when the job fires, that run fails.
  • Each run records its start time, finish time, whether it succeeded, and up to 8,000 characters of output.
  • The last 50 runs of each job are shown in the Cron Jobs tab.

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Pause, edit or delete a job

  • Pause stops the job from running without deleting it. Click Resume to start it again. A paused job still counts towards your plan limit.
  • Edit changes the name, command or schedule.
  • Delete removes the job from your server and frees its slot.
Cron jobs are managed by the person who created the app, while they still have Developer access or higher to its server.

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Good to know

  • An app is one container, so a job shares its memory and CPU with the app. Keep heavy jobs to quiet hours.
  • Long-running workers that never exit are not a fit for cron. Symplax does not run background worker apps yet, because every app must serve HTTP.
  • For a one-off task on each deploy, such as migrations, use a release command instead.