Praecise Skerry/ Reference/ Universal Commerce Protocol
Universal Commerce Protocol7
Called by a platform, not by a partner, and not with an API key. The platform names its profile in UCP-Agent and signs each request (RFC 9421, ES256) with a key that profile publishes; the customer must have listed that profile. Paths, fields, statuses and messages follow the protocol's 2026-08-25 version, the only one spoken. What the business decides about a checkout is a 200 with messages; a checkout or order that is not there is a 200 with ucp.status: "error" and messages; protocol errors are { code, content }, not Skerry's envelope. A preview, off by default.
- The customer's business profileget/ucp/{customer_id}/.well-known/ucp
- Create a checkout. Answers 201 with the checkout, pricedpost/ucp/{customer_id}/checkout-sessions
- Read a checkout. Only the platform that opened it finds itget/ucp/{customer_id}/checkout-sessions/{id}
- Replace a checkoutput/ucp/{customer_id}/checkout-sessions/{id}
- Complete with the card processor's payment token, for the checkout's exact totalpost/ucp/{customer_id}/checkout-sessions/{id}/complete
- Cancel a checkout that is neither completed nor canceledpost/ucp/{customer_id}/checkout-sessions/{id}/cancel
- Ucp orders getget/ucp/{customer_id}/orders/{id}