Network failures can cause clients to resend operations. The server must distinguish a retry from a new business request.
Evaluation approach
Bind transaction keys to account, content and lifetime. Do not accept different payloads under the same key.
Application example
If a payment response is lost, retrying must not charge twice. Return the prior result safely.
Limits and considerations
An idempotency key alone provides neither replay protection nor user authorization.
What should users see after a lost response?
Allow status retrieval using the original transaction identifier. Show pending and failed states accurately so uncertainty does not encourage a second charge.
Checks and decisions
- Verify content matches
- Test concurrent attempts
- Store results safely
Sources
The primary references above provide the technical basis. Example workflows and evaluation suggestions are this publication’s explanations, not independent test results for a particular product.