Abstract: A method to process webhook calls is described. The method comprises receiving, from a callback producer server and at a proxy callback interface of a proxy server, a webhook call comprising a webhook channel address and payload callback data. A callback record is stored in a proxy server database, the callback record comprising a sequence number and the payload callback data. A callback query is received, from a callback client and at a query interface of the proxy server, the callback query identifying the webhook channel address. The callback record is identified, using the callback query, the callback record, and provided, responsive to the callback query, from the query interface to the callback client.

Abstract: In some embodiments, a method to generate a user interface for a subscription management system may include receiving first order data relating to a first subscription offering, receiving second order data related to a second subscription offering, combining the first and second order data into a subscription data structure that, calculating a combined one-time payment amount for both the first and second subscription offerings based on the quantity data, calculating a combined periodic monthly subscription payment amount for both the first and the second subscription offerings based on the quantity and period data, and/or causing presentation of both the combined one-time payment amount and the combined monthly subscription payment amount in the user interface for the subscription management system.