Book the delivery the visitor was quoted: only the quote_id the quote returned, before its expires_at, and only from the session lineage that was shown it. Dispatches the order to a provider, billed to the merchant. Idempotent per quote: a retry, a double click or a new session for the same form gets the same answer and never a second delivery. status is booked, or booking_failed when no delivery could be confirmed (the order is kept and the business follows up); reference identifies the order and tracking_url is the delivery's tracking page when there is one.

ORDER_INTAKE_QUOTE_EXPIRED and ORDER_INTAKE_QUOTE_ABOVE_LIMIT (409) ask for a new quote. ORDER_INTAKE_DAILY_LIMIT (429) when the form reached its daily order limit. A malformed quote_id is VALIDATION_ERRORS (422). Refusals are the uniform FORBIDDEN (403) or SESSION_EXPIRED (410); RATE_LIMITED (429) and ORDER_INTAKE_UNAVAILABLE (503) carry Retry-After.