The Actian DataConnect Studio API invoker (formerly known as the REST Invoker) must be used to build process workflows to interact with web service applications. There are some purpose-built, map connectors available but the Studio API invoker provides a consistent and standardized way to connect to any REST or SOAP interface. It also provides more flexibility because you can exercise any method or operation of the API that a connector may not support. Also, the less tightly-coupled nature of the invoker allows easier maintenance as the API changes over time.