When you need one request, later
Plenty of tasks are a single delayed call: trigger a rebuild after an embargo lifts, publish something at a specific hour, expire a promotional flag at midnight, or kick off a job once a maintenance window opens.
None of that justifies running a scheduler. Provisioning a cron host, or adding a scheduled function with its own deployment and permissions, is a large amount of machinery for one HTTP request that happens once.
Testing what happens on a schedule
Scheduled behaviour is unpleasant to develop against, because the feedback loop is as long as the schedule. Being able to fire the exact request your scheduler would send, at a time you pick a few minutes from now, collapses that loop to something workable.
It is also useful for reproducing a bug that only appears when a callback arrives late, or for confirming that a receiving endpoint behaves correctly when the same request arrives twice.
Make the receiving endpoint idempotent
Any delivery system will occasionally send twice - a retry after a timeout where the request actually succeeded is the common case. If your endpoint charges a card, sends an email or creates a record, a duplicate is a real problem rather than a theoretical one.
The standard defence is an idempotency key: include a unique identifier with the request, and have the receiver record which identifiers it has already processed and ignore repeats. This is worth doing whether or not you expect duplicates, because the day you need it is the day you cannot add it.
Frequently asked questions
- Can I schedule a repeating request?
- This tool fires a single request at a chosen time. For a recurring schedule you want a real cron job - use the Cron Parser to check your expression is correct first.
- Can I send custom headers and a body?
- Yes. Method, headers and body are all yours to set, so the request can carry authentication or a signed payload exactly as the receiver expects.
- What happens if the destination is down at that moment?
- The delivery attempt is recorded with its result, so a failure is visible rather than silent. Build your receiver to tolerate a retry arriving twice.
- Do I need an account?
- No. Scheduled requests you create are remembered in your browser under My stuff, where you can review or cancel them before they fire.