Why This Matters

Webhook providers retry aggressively. If your consumer is not idempotent, duplicate deliveries can create duplicate side effects and corrupt state.

Patterns That Work

1. Use an idempotency key per delivery event.
2. Persist the key in a durable store before side effects.
3. Acknowledge only after successful commit.
4. Retry transient failures with backoff.
5. Route exhausted retries to a DLQ for manual or automated replay.

Implementation Notes

• Keep handlers stateless and deterministic.
• Log every failed attempt with correlation IDs.
• Emit metrics for retry count and DLQ growth.

These three building blocks make webhook systems predictable under failure.