Idempotent Request

Definitions

1. An HTTP request that produces the same result regardless of how many times it's executed. GET, PUT, DELETE, and HEAD are idempotent by design. POST is not -- creating a resource twice creates duplicates. Making non-idempotent operations safe for retry (via idempotency keys) is critical for reliable distributed systems.

   In plain English: A request that gives the same result whether you send it once or ten times -- safe to retry without side effects.

   Example: "PUT /users/123 with the full user object is idempotent -- calling it 5 times results in the same state. POST /users is not -- you'd get 5 users."

Related Terms

• Footgun
• idempotency
• Architecture
• Consume
• API Versioning
• HATEOAS
• Content Negotiation
• API Rate Limit Header