Dead Man’s Switch

DMS overview

What Dead Man’s Switch is and when to use it.

What DMS is

Dead Man’s Switch (DMS) is an optional check-in for a task. After CronFox starts a run, your process must ping a unique URL. If that ping never arrives within the grace period, CronFox marks the run as missed and can alert you.

DMS answers a different question than HTTP status codes:

  • HTTP success → CronFox reached your URL and got a response
  • DMS ping → your job logic finished the work it was supposed to do

When to use it

Use DMS when:

  • The HTTP endpoint only enqueues work, and success means a worker finished later
  • You need proof that a long script completed, not just that it started
  • Silent partial failures are worse than an extra ping from your code

Skip DMS for simple health pings where the HTTP response alone is enough.

How it works

  1. You enable DMS on a task and set a grace period (seconds).
  2. CronFox creates an execution when the job runs; DMS starts as pending.
  3. Your process calls https://ping.cronfox.com/{task_id}/{token}.
  4. On a valid ping, CronFox records the check-in as OK.
  5. If the grace period elapses with no ping, the run is treated as missed and can fire DMS Missed Ping notifications.

What you need

  • A task that can call an outbound HTTP URL after finishing work
  • The ping URL (available after the task is created with DMS enabled)
  • DMS missed alerts turned on if you want channel notifications

Next steps

  1. Enable DMS on a task
  2. Wire the Ping URL into your process
  3. Configure Missed pings alerts