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How to run one-time cronjobs

The best use case for one-time cronjobs (cronjobs that run once at a specific time) is scheduling a task once at a specific time and it won’t recur ever again. For example, I schedule an email blast to notify new IP addresses before they’re in use.

For other use cases, there are some better ways:

  • If you’d like to process one item at a time, instead of creating a one-time cronjob with the item data, you should store those items (with their scheduled times if necessary) in your database, and set a cronjob every few seconds or minutes to retrieve and process those items.
  • If you’d like to process a multi-step cronjob, instead of creating a one-time cronjob with the next step data, you should redirect to the new URL. FastCron will follow the HTTP redirection.

If you still need to create/run one-time cronjobs, follow the instructions below.

Create one-time cronjobs manually

  • Click new Cron Job
  • Enter the URL to your cron script.
  • Click the Expression button next to When to call
  • Enter the time into the Expression field, e.g. Feb 14, 2030, 7:30
  • Click Save changes.

And that’s it. You can hover/click on the time pattern field e.g. Feb 14, 2030, 7:30 in the example above, and it’ll show the next execution time so you can confirm the time settings are correct.

Run one-time cronjobs using API

To programmatically run one-time cronjobs, you can create a cronjob (with When to call: Manual), then schedule to run it at a specific time using cron_run.

Terminal window
curl -X POST "https://app.fastcron.com/api/v1/cron_run" \
    -H 'Content-Type: application/json' \
    -d '{
        "token": "YOUR_API_TOKEN",
        "id": CRONJOB_ID,
        "time": 1905821065
    }'

The command above will run your cronjob at Friday, May 24, 2030 2:44:25.

You can also attach a payload to the execution time like this:

Terminal window
curl -X POST "https://app.fastcron.com/api/v1/cron_run" \
    -H 'Content-Type: application/json' \
    -d '{
        "token": "YOUR_API_TOKEN",
        "id": CRONJOB_ID,
        "time": 1905821065,
        "payload": "test=value&name=value2"
    }'

The command above will run your cronjob at Friday, May 24, 2030 2:44:25 with the payload test=value&name=value2.