Your first check-in

In this tutorial you will send a check-in to a real Triple Pat timer and see the service record it. All you need is the web.

The test timer

Every timer has a UUID, which is both its identifier and its credential: anyone who knows the UUID can check in. For learning and testing, we operate a public timer using the UUID Wikipedia uses as an example:

550e8400-e29b-41d4-a716-446655440000

Because the UUID is published here, anyone can check in with it — including you, right now.

Send a check-in

Open this URL:

https://triplepat.com/api/v1/checkin/550e8400-e29b-41d4-a716-446655440000

The service replies with the timer’s new state:

{
  "lastCheckinTime": "2026-08-02T12:57:28Z",
  "uuid": "550e8400-e29b-41d4-a716-446655440000"
}

lastCheckinTime is the moment your check-in arrived. Reload the page and watch the timestamp move.

Read the timer

Now open this URL:

https://triplepat.com/api/v1/getlastcheckin/550e8400-e29b-41d4-a716-446655440000

The reply looks the same, but this URL only reads the timer. Reload it as often as you like; the timestamp stays where your last check-in left it, until someone checks in again.

What just happened

You did the only thing a monitored system ever needs to do: tell Triple Pat that everything is fine by checking in. Nothing else is required of it. The Triple Pat phone app is the other half: with a timer of your own in it, the app raises an alarm when the check-ins stop, and that is what makes the check-ins worth sending. A browser, curl, a cron job, and an alerting system’s webhook all do exactly the same thing here, which is why any of them can be the thing that checks in.

Next steps