Articles tagged #backend-engineering

2026-08-18 Tutorial

Idempotency: The Claim-First Pattern That Stops Double Charges

Retries are guaranteed in distributed systems. Duplicate side effects are not. A deep dive into idempotency keys, the claim-first ledger pattern, and how to implement it in Django and PostgreSQL.

#backend-engineering #aws #django #postgresql #distributed-systems · 15 min read

2026-08-18 Tutorial

Lambda Invocation Models: The Architecture Decision Hiding in Plain Sight

Synchronous, asynchronous, and poll-based invocation give the same Lambda code completely different failure modes, retry behavior, and scaling. A field guide to choosing, plus the three front doors for HTTPS: Function URLs, API Gateway, and ALB.

#aws #lambda #serverless #backend-engineering #distributed-systems · 11 min read