The Web Application Description Language (WADL) is a machine-readable XML description of HTTP-based web applications (typically REST web services).

WADL models the resources provided by a service and the relationships between them.
WADL is intended to simplify the reuse of web services that are based on the existing HTTP architecture of the Web.
It is platform and language-independent and aims to promote the reuse of applications beyond the basic use in a web browser.