Return Retry-After when a client should back off
Tell API clients when another attempt may succeed instead of leaving them to guess a retry delay.
Apis
Do not page without deterministic ordering
Give paged database queries a fully unique order so rows with the same sort value cannot move unpredictably between pages.
Use idempotency keys for retryable writes
Make a retried write replay the same operation instead of creating a duplicate side effect.
Prefer keyset pagination for deep lists
Use seek-based pagination when users move through large ordered result sets.
Use ProblemDetails as your API error contract
Return one predictable error shape instead of inventing a new JSON format for every failure.