Rate Limits and Idempotency

Defines how to prevent duplicate side effects and avoid throttling instability under production load.

• Stable client-generated operation identifiers per business action.
• Request queue or worker model supporting adaptive concurrency.
• Clock and retry policy alignment across distributed services.

• Mutating requests include idempotency key scoped to one logical operation.
• Throttle responses signal temporary request-rate exhaustion.
• Client retries maintain same idempotency key and adjusted pacing.

1. Generate idempotency key before first attempt and persist with operation context.
2. Submit request through concurrency-controlled execution lane.
3. If throttled, delay next attempt using exponential backoff and jitter.
4. Reuse key until operation reaches terminal known outcome.

• Duplicate request with changed payload under same key.
• Burst traffic leading to sustained throttling and queue growth.
• Uncertain request outcome due to timeout without response receipt.

• Never rotate idempotency key while operation outcome remains unknown.
• Cap retries and move unresolved operations to manual review queue.
• Throttle retries globally when system-level 429 responses spike.

• 429 response rate, queue depth, and retry backlog by endpoint family.
• Idempotency replay hit rate and duplicate-prevention effectiveness.
• Percent of operations requiring manual resolution after retry exhaustion.