Web Services Description Language (WSDL) is a standard specification for describing networked, XML-based services. The WSDL specification was initially developed by IBM(R) and Microsoft(R). It provides a simple way for service providers to describe the basic format of requests to their systems regardless of the underlying run-time implementation.
WSDL defines an XML format for describing network services as a set of endpoints that operate on messages that contain either document-oriented or procedure-oriented information. The operations and messages are first described abstractly and then bound to a concrete network protocol and message format in order to define an endpoint. Related concrete endpoints are combined into abstract endpoints (services). WSDL is extensible to allow description of endpoints and their messages, regardless of what message formats or network protocols are used to communicate. This means that interfaces are defined abstractly using XML schema and then bound to concrete representations that are appropriate for the protocol.
A WSDL document describes where a Web service is deployed and what operations that service provides. Using WebSphere(R) Studio a business service provider can deploy Java(TM) beans, DADX-described queries and remote procedures, or existing URLs as a Web service and generate a WSDL document that describes the service. A business service client can generate a Java proxy from a WSDL document, thereby providing an easy-to-use Java interface to the Web service.
WSDL documents allow developers to expose their applications as network-accessible services on the Internet. Through UDDI, other applications can discover WSDL documents and bind with them to execute transactions or perform other business processes.
For more information on the WSDL specification, refer to www.w3.org/TR/wsdl.