IDEMPOTENCY-KEY-EDI

HTTP duplicate-prevention pattern applied to EDI APIs.

Definition

The Idempotency-Key header (IETF draft 'The Idempotency HTTP Header Field') is generated client-side (typically UUID v4) and included in each POST. The server stores the key + response for N hours. If the same key returns, the cached response is replayed rather than re-executing. Adopted by Stripe, PayPal, and modern EDI APIs (Stedi, Cleo).

Origin

Stripe popularises the pattern in 2015. IETF draft draft-ietf-httpapi-idempotency-key-header under adoption.

Example in context

POST /v1/invoices with header Idempotency-Key: 4d1f8a3c-8f29-4e2c-8b71-9e8c8f3a3c5d → if network timeout, retry with same key → server returns the previous response.

Related terms

• WebHook spec — sibling pattern.