Idempotency Key

Definitions

1. A unique token sent with an API request to ensure that retrying the same operation produces the same result without side effects. Critical for payment APIs and any operation where duplicate execution would be harmful.

   In plain English: A unique ID attached to a request so that if you accidentally send it twice, the server only processes it once.

   Example: "Every payment request includes an idempotency key — if the client retries due to a timeout, Stripe recognizes the duplicate and returns the original result."

Related Terms

• Idempotent
• idempotency
• Dead Letter Queue
• Idempotent Pipeline
• Webhook Retry
• Outbox Pattern
• Backend for Frontend
• API Composition