POST /api/public/orders/{orderId}/cancel accepts an optional Idempotency-Key header, the same way the refund does: 1 to 255 printable ASCII characters, a new value for every cancellation and the same value when you retry that cancellation.
This page needs JavaScript. The same content is available as Markdown: /changelog/2026-10-25-cancel-idempotency-key.md. Every document for agents is listed in /llms.txt.