What Is the Web Service node?
The Web Service Activity Node allows the server to call a Web Service and use any returned information in the process. Any web service that supports the SOAP protocol and that uses "document/literal" style can be used. Currently, "RPC"-style web services are not supported by the activity node.
The Web Service node has a built-in wizard to aid in the construction of the SOAP XML that is sent to the web service, and a built-in output wizard to let you know what XML elements are expected as output. That information is retrieved from the web service’s WSDL (Web Service Definition Language) document.
Because a web service takes XML as input and returns XML as output, the Web Service node uses much of the same functionality as the XML activity node. You can think of a Web Service node as both an XML Builder and an XML Parser, with a web service call in-between. Like the XML node, XML input is built (and the output parsed) as JavaScript objects so that elements or their contents may be accessed within the process, especially using the Assign and Branch nodes.