Idempotency & retries

Safe retries for create and money-moving POSTs.

Idempotency-Key

Send header Idempotency-Key: <unique-string> (max 128 chars). Replays for 24 hours return the original response. A reused key with a different body returns 409 idempotency_conflict.

Required on

• Escrow release / dispute (and other money-moving escrow actions)
• Verification confirm

Recommended on all create POSTs (checkout, invoices, offerings).