I keep running into (and hearing about) a specific kind of bug that never throws an error — an API you depend on quietly changes its response shape. A field disappears. A number becomes a string. Something that was always present is suddenly null. Nothing crashes immediately. It just produces wrong or missing data somewhere downstream, and you find out from a bug report, not a log.
I'm curious how common this actually is outside my own experience, so — genuine question, not a pitch:
Has this happened to you, with a third-party API or even an internal one your own team owns?
How did you find out it happened — a user report, a stack trace somewhere unrelated, manual debugging?
Do you currently do anything to catch this kind of thing before it bites you (contract tests, monitoring, or just... hoping)?
