idempotent
Pronunciation: eye-DEM-poh-tent
Describing an operation that produces the same result regardless of how many times it is applied, provided inputs remain unchanged.
Full Definition
In the context of developer tools and API design, an operation is idempotent if executing it multiple times has the same effect as executing it once. For HTTP methods, GET, PUT, and DELETE are conventionally idempotent, while POST is not. Idempotency is a critical design property for REST APIs, message queues, and database migrations, as it ensures that retries after failures do not cause unintended side effects. Editors must spell this term correctly—'idempotent', not 'idempotant' or 'idempotant'—and ensure it is not confused with 'immutable' (which means unchangeable) or 'stateless' (which relates to session state).
Usage
Usage note: Spell carefully: 'idempotent' (not 'idempotant'). Ensure the concept is accurately described — it concerns repeated operation effects, not immutability.
In Context
- "The DELETE endpoint is idempotent: calling it multiple times on the same resource returns 200 on the first call and 404 on subsequent calls without causing errors." — REST API design guide
- "Database migration scripts should be written to be idempotent so they can be safely re-run." — Engineering best practices document