Health checks that prove the product works

What I tried

Couri footers can carry the sender's photo. The first health check asked only whether each service was running.

Why I chose differently

A service can be running while unable to do its job. I wanted every deploy to prove the product works.

What I chose

Deploys now run the tests first. Once live, they exercise what the product actually does before they are allowed to finish. Storage is set up correctly on every new deployment. To prove the check, I set things back the old way deliberately and watched the deploy refuse to go ahead.

The principle

"Healthy" should mean the product can do its job. Prove a safety check by tripping it on purpose.