Executive TL;DR
- Idempotency in APIs is complex and requires careful consideration.
- Using idempotency keys can help prevent duplicate requests.
- Implementing idempotency can be an enormous architectural shift.
The Buzz Score
The Internet’s Verdict: 70% Hyped, 30% Skeptical
Understanding Idempotency
Idempotency means that an operation can be repeated without changing the result. However, in practice, this can be difficult to achieve.
Challenges with Idempotency
One of the main challenges with idempotency is handling duplicate requests. As one forum user noted:
This seems to assume retrying a command should result in the same response, but I am not sure I agree. Idempotency is about state, not communication. Send the same payment twice and one of them should respond “payment already exists”.
Best Practices for Implementing Idempotency
Another user shared their experience with implementing idempotency:
A couple of years ago, we experienced a silent data corruption incident in our checkout process due to this specific edge case. A user would generate the idempotency key by loading the front-end application, adding item(s) to their cart, submitting their order but timing out. The user would then navigate back to the front-end application and add another item and submit the order again.
To safely accomplish idempotency, you have to follow certain steps, including acquiring a distributed lock on the idempotent key and checking for the existence of a key in your persistent store.
Focus Keyword: Idempotency APIs
