WSDL stand for (Web Services Description Language) which is often used in combination with SOAP and XML Schema to provide web services over the Internet and via Internet client program connecting to a web service can read the WSDL to determine what functions are available on the server. Any special datatypes used are embedded in the WSDL file in the form of XML Schema. The client can then use SOAP to actually call one of the functions listed in the WSDL. The Web Services Description Language is an XML based language used to describe the services a business offers and to provide a way for individuals and other businesses to access those services electronically. WSDL is the cornerstone of the Universal Description, Discovery, and Integration (UDDI) initiative spearheaded by Microsoft, IBM, and Ariba. UDDI is an XML-based registry for businesses worldwide, which enables businesses to list themselves and their services on the Internet. WSDL is the language used to do this. A WSDL document is a concrete description of a Web service that includes both abstract and concrete elements. WSDL describes the abstract functionality of a service and provides a framework for describing the concrete details of a service description.