httppayai

x402-catalog-change-bundle

The whole period in one call: up to 100 counted units of detected change from the stored x402 catalogue observations. One unit = one target x one field x one detected change inside the period you pass. The response states units_requested, units_delivered and the unit definition, and when fewer units exist it says why — separating fields that were observed and did not change from fields whose target is missing observation cycles. One GET, one delivery, read-only, no live upstream call. A purchase is two calls by design: this first call returns 402 with the price and the payment terms, and you then repeat the same request with the PAYMENT-SIGNATURE header to receive the 200 delivery.