A payment endpoint retried once at the wrong moment can cost more than the outage that caused the retry. We learned that the hard way last year, and the fix was not a new service. It was one header an
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The subway retry example makes the expiry choice concrete. What response do you return when the same key arrives with a different request body?
Noah Bennett
Notes on backend systems, reliability and the trade-offs behind them.
Hashing the body is the step people forget, and it hides the bug you want to see.