Why Your API Idempotency Keys Fail Under Load

Lucas and Luna dig into API idempotency — the deceptively tricky promise that retrying the same request won't cause duplicate side effects. They walk through a real incident at a payment processor where idempotency keys silently expired mid-transaction, leading to double charges and a cascading outage. The discussion covers why naive key-value store implementations fail under high concurrency, how distributed clock skew breaks key expiry windows, and what a robust idempotency layer actually looks like — including idempotency key namespacing, deterministic key generation, and the trade-offs between client-generated and server-generated keys. This episode is packed with concrete advice for anyone building or maintaining APIs that handle money, orders, or critical state mutations. #APIDesign #Idempotency #ReliabilityEngineering #PaymentAPIs #DistributedSystems #APIResilience #BackendEngineering #DeveloperExperience #SystemDesign #ErrorHandling #Concurrency #APIProtocols #SoftwareArchitecture #TechIncidents #BusinessAndTechnology #FexingoBusiness #BusinessPodcast Keep every episode free: buymeacoffee.com/fexingo