Engineering Notes
Security & Webhooks
Systems & Webhook Architecture
Deep technical teardowns on Stripe signature mechanics, idempotency traps, and zero-loss distributed ingress.
Why Stripe Webhook Replays Fail Signature Verification (And The Re-Signing Fix)
Why standard `stripe.webhooks.constructEvent()` throws "Timestamp outside the tolerance zone" on retried or replayed webhooks older than 300 seconds, and the cryptographic re-signing architecture required to solve it.
Distributed SystemsThe SQS Deduplication Trap: Why Naive Webhook Queues Silently Drop Payment Retries
Rolling your own SQS + Lambda webhook queue looks simple in 20 lines of code until database connection exhaustion or Lambda OOM crashes turn your unique constraint dedupe into a silent event incinerator.