This chapter discusses multiple technologies related to non-RESTful web services. It examines Simple Object Access Protocol (SOAP), which is an enabling technology. The chapter discusses Web Services Description Language (WSDL), which is used one way or another in various implementations of non-RESTful web services. It also examines JAX-WS, originally created by Sun Microsystems and now supported by Oracle. The chapter also looks at Windows Communication Foundation (WCF), which provides Microsoft's implementation of non-RESTful web services. A web service that uses WSDL to define the interface which commonly employs SOAP, would be considered "non-RESTful". However, it is possible to configure a WSDL interface that runs directly using Hypertext Transfer Protocol (HTTP). SOAP is a protocol that sends and receives structured information in the form of Extensible Markup Language (XML) documents, in a distributed environment. JAX-WS is an Application Programming Interface (API) for Java that is used to create web services.