Engineering blog

How the transactional outbox pattern guarantees you never lose a webhook — commit the event and its deliveries in one Postgres transaction, then return 2xx.

Use FOR UPDATE SKIP LOCKED to turn Postgres into a reliable job queue — no Redis, no Kafka — with crash recovery via leases and low latency via LISTEN/NOTIFY.

Retry failed webhooks without hammering a struggling endpoint: exponential backoff with jitter, a dead-letter queue, and per-endpoint circuit breakers.

Exactly-once delivery is a myth over a network. Here's what at-least-once really means and how an idempotency key lets receivers dedupe safely.

Securely verify incoming webhooks with HMAC-SHA256, constant-time comparison, timestamp tolerance, and replay protection — covering Stripe and GitHub.

Most systems claim durability but never test it. Here's a kill -9 test that proves a webhook pipeline loses zero events across a crash.