Idempotency keys: stop charging customers twice when they double-click Pay

A customer taps Pay. The spinner hangs for four seconds, so they tap it again. Or their phone drops from Wi-Fi to mobile data halfway through the request, and the app retries. Your server sees two identical POST requests, and unless something stops it, the customer is charged twice. Nothing is broken in that story. The network is doing what... Weiterlesen: Idempotency keys: stop charging customers twice when they double-clic…