Our retries turned a blip into a full outage

Synchronised retries are an attack on your own service. Exponential backoff with jitter and a cap, plus a circuit breaker that stops trying entirely once failures dominate. Without jitter every client retries at the same instant, which is precisely the thundering herd.

It names what failed, what was expected, and what to do next. "Invalid input" fails all three; "expected a date in YYYY-MM-DD, got 12/03/2026" passes the first two and hints at the third, which is usually enough.