Healthchecks.io pinging API has always been based on UUIDs. Each Check in the system has its own unique and immutable UUID. To signal a start, a failure, or a particular exit status, clients can add more bits after the UUID: This is conceptually simple and has worked quite well. It requires no additional authentication. The UUID value is the authentication, and the UUID “address space” is so vast nobody is going to find valid ping URLs by random guessing any time soon.