Web Application Description Language (WADL) is a machine process-able XML description of HTTP-based Web applications, such as REST web services.
Web Application Description Language (WADL) is a machine process-able XML description of HTTP-based Web applications, such as REST (rest) web services.
The description of HTTP-based applications and services is achieved by modeling, from the HTTP interaction standpoint, the provided resources and the relationships between them.
WADL intends to be the REST equivalent of SOAP's Web Services Description Language (wsdl), which can also be used to describe REST web services.
For more information, see the Web Application Description Language - W3C Member Submission 31 August 2009 and the W3C Team Comment on it.