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TechnologyPhD15 m+180 XP
Webhooks & event-driven architecture: building reactive systems
Webhook security, idempotency, retry logic & the event patterns behind scalable automations
Webhooks are push notifications from external services. They're simple in concept and surprisingly tricky in practice. The core problems: (1) delivery is not guaranteed — the sender will retry, so your handler must be idempotent; (2) order is not guaranteed — events can arrive out of sequence; (3) verification is critical — anyone can POST to your webhook endpoint, so you must verify the signature. Stripe's webhook model is the gold standard — study it.
Key Points
- ▸Idempotency: processing the same event twice must produce the same result
- ▸Return 200 immediately, process async — avoid timeouts
- ▸Verify HMAC signatures before processing anything
- ▸Store event IDs to deduplicate retries