LESSON 3.3
Idempotency and safe retries
Learn key techniques and workflows in System Design Foundations.
7m
intermediate
8,659 students
Overview
Any request can be delivered twice. An idempotency key lets the second delivery return the first result instead of charging the card again.
In this lesson you will:
- Make write endpoints safe to retry
- Accept and store idempotency keys
- Retry with backoff and jitter, not in lockstep
Pro Tip
Retries without jitter turn one blip into a synchronised stampede.