Check-in API

Timer UUIDs

Every timer has a UUID, assigned when the timer is created in the phone app. The UUID is both the timer’s identifier and its credential, so anyone who knows the UUID can check in to the timer. A UUID looks like:

550e8400-e29b-41d4-a716-446655440000

Check-in URL

https://triplepat.com/api/v1/checkin/<uuid>

Requesting the URL with either GET or POST records a check-in for that timer and returns the timer’s new state as JSON:

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

There is no separate authentication; the UUID is the credential. Keep your timer’s UUID private.

Check-in email addresses

<uuid>@checkin.triplepat.com
<uuid>@checkin.triplepat.net

For example, an email to either (or both!) of these addresses checks in to the public test UUID:

550e8400-e29b-41d4-a716-446655440000@checkin.triplepat.com
550e8400-e29b-41d4-a716-446655440000@checkin.triplepat.net

An email to either address checks in to that timer. The subject and body are ignored, and the address is not case-sensitive. Every server accepts mail for both domains. The check-in is recorded when the email arrives, typically a minute or two after it is sent.

One email checks in to one timer. Sending it to the same UUID at both domains is fine and counts as one check-in, but an email addressed to two different UUIDs bounces and checks in to neither. An email to a UUID that has no timer bounces too.

If our servers can’t record a check-in right away, your mail system tries again, either at a different server or later at the same one, so a brief Triple Pat outage delays the check-in instead of losing it.

The public test UUID

The example UUID above is one UUID Wikipedia uses as an example. We have included it in our system as a shared test timer. Because we publish it here, anyone can update it. Feel free to use it while building or testing an integration, but be aware that everyone else can use it as well.

Full API documentation

See our API docs for the complete API.