System Design Patterns: From Fundamentals to Real Systems
Vote

0% completed

​

Idempotency

1. The Incident

The previous lesson added retries and prevented errors for 500 customers per day. Those retries introduce a new correctness risk.

A customer clicks Pay for a $499 course bundle, and your service calls the payment provider. The provider charges the card, but its successful response is lost in transit. After a 100 ms delay, the timeout policy sends an identical request that appears new to the provider. The customer is charged again and sees a total of $998.

.....

.....

.....

Like the course? Get enrolled and start learning!

Reading Progress

0%

Vote for new content