Reference · Computing
Idempotency as a system property
A reference for designing repeated requests so retries do not create repeated effects.
Definition
An operation is idempotent when applying it more than once has the same externally visible result as applying it once. The property belongs to the operation and its state transition, not to the client’s good intentions.
Design cue
Give retries a stable key and make the resulting state observable. A duplicate request should resolve to the existing result or to a clearly documented conflict, rather than silently performing the side effect again.
References and sources