System Design Drill Day 9: Idempotency Keys for Payments and Retries
A customer taps "Pay" on a shaky mobile connection. The charge goes through on the server, the response never reaches the phone, and the app retries. Whether the customer is now charged twice depends
Responses
Markdown supported · ⌘↵ to post
Abhinav Sharma
Founder of Impact Gate. See who breaks before you change an API.
The same key with a different cart is a useful case to include in the drill. The happy-path retry test could pass while that mix-up still returns a result for the wrong request.