XRDL is a language and tools for automatic client generation for XML-RPC services. It provides a way to create simple service definitions for XML-RPC services. It is inspired by WSDL, but aims for ease of use in the spirit of XML-RPC. It supports exporting complex (recursive) types, as well as methods. It includes a number of tools, allowing automatic XRDL generation for servers and clients written in PHP or C++/Qt.