A few years ago, I was integrating with an API that shall remain nameless. It told me almost nothing — no error messages, no logs worth reading. Just HTTP status codes and a dashboard with exactly one metric: failed requests over total requests.

It started at 1/1. Then 2/2. Then 13/13. Then 32/32. A perfect record of failure.

I was deep in it. Change something, re-send, change something else. Then I looked up, and the dashboard read:

67/68.

One request had worked.