WSDL file format contains description of websites, service end ports, data definitions, messages, operations and protocols in standard XML text format. WSDL XML format is maintained by W3C.org, and is used mainly for data source channel definition purposes and remote access to services. This files often describes information at an abstract level and may need to be implemented using separate service file.

WSDL files can be used with various interfaces, for example those of ASP.NET, C/C++ and Java environments. Microsoft Visual Studio includes a program Wsdl.exe, which can be used for creating WSDL files. WSDL files can be edited manually in any standard text editor, given the user has the necessary knowledge about the implementation. WSDL format was designed by IBM and Microsoft for SOAP-related purposes in 2000.