The document outlines a general Application Program Interface (API) to X-on's Hosted Call Processing Services. The main product to which the API applies is X-on Contact Centre which provides inbound and outbound call routing to contact centres. However, sections of the API can be configured with other X-on products and this document should be read in conjunction with proposals and specifications concerning these where relevant.

The API runs over standard https web transport between X-on servers and client servers. The data protocol can use either SOAP/XML format or JSON. The latter is preferred where there is a choice, being more lightweight.

The API is split into three types of communication. The PDF summarises these and likely applications.