Pega 7 Platform includes standard activities, flows, and flow actions that you can use to start and advance flows without using user forms. These rule (collectively known as the Process API) can support Pega 7 Platform business processing through Service Oriented Architecture (SOA) facilities including agents and service activities.
Business process management applications can use an external portal or external system and call Pega 7 Platform services that in turn call Process API rules to create work items, advance the work items through a flow, perform assignments, and so on.
Do not confuse the Process API with the Engine API, a collection of documented Java interfaces also known as the Public API.
To see a list of the Process API rules, select Designer Studio > Process and Rules > Processes > APIs.