API Testing / Quiz
Webhook Reliability
Retries, idempotency, signature verification, and ordering, testing the async callbacks that quietly run half the internet.
- Difficulty
- Hard
- Format
- Quiz
- Points
- 200
- Estimate
- 9 min
// MISSION BRIEF
Your Mission
Webhooks are async, at-least-once, and out-of-order by nature. A consumer that assumes exactly-once, in-order delivery will double-charge, mis-sequence, or get spoofed. Test like the network is hostile, because it is.
// FIRST CONTACT
Battle teaser
A payment provider retries a webhook when your endpoint is slow, so you receive the same `payment.succeeded` event twice. The consumer must be:
- AIdempotent, dedupe on the event id so processing twice has the same effect as once
- BConfigured to reject duplicates with a 409
- CIgnoring all retries
- DFaster, so retries never happen
Answers, scoring, hints, and the full battle stay sealed.
// SKILL TAGS
apiwebhooksidempotencyhmac