idempotency · shipping · also Idempotence

Idempotency

Idempotency is the property that repeating the same operation with identical inputs has the same intended effect as performing it once.

HTTP idempotency does not require identical responses or prohibit a separate log entry for each attempt (RFC 9110, section 9.2.2). It is not a durability or exactly-once execution guarantee. Repeating an assignment after another writer changes the value can overwrite that intervening update; duplicate suppression and concurrency control address distinct concerns.

Relations

related

idempotency-key, retry-deduplication, io-timeout

Citations

1. RFC 9110: HTTP Semantics (June 2022), section 9.2.2, Idempotent Methods. (accessed 2026-10-15)
2. Storage timeouts: an expired timer is not a cancelled write (accessed 2026-10-15)

JSON: /data/terms/idempotency.json