I have been working with a number of RESTful services lately. Unlike SOAP, some RESTful services do not have well defined responses. SOAP based services are (of course) defined in a WSDL, making the response easily parsible. The WSDL thus provides a formal contract between service provider and consumer. This is not the case with REST. RESTful service providers have not adopted WADL and I've seen everything from JavaScript to XML returned. In the worst case, RESTful providers are returning XML without an XSD. While RESTful providers generally provide APIs, this lack of a formal contract results in lost productivity. For example, there are some RESTful services in which I want to parse the response XML. Without a referenced XSD, I have lost productivity in researching APIs to figure out the response. This is unnecessary and something which must be improved in REST.