The core of WDDX is the XML vocabulary, and a set of components for each of the target platforms to serialize and de-serialize data into the appropriate data structure and a document type definition (DTD) that describes the structure of standard data types. Functionally, this creates a way to move data, its associated data types and descriptors that allow the data to be manipulated on a target system between arbitrary application servers.
WDDX is based on XML 1.0, which is a W3C Recommendation. Other W3C efforts now in the works will have obvious application to WDDX when they are completed, including the XML-Data proposal and metadata formats such as the Resource Description Framework (RDF). The WDDX DTD supports versioning, allowing these and other enhancements to be folded into the specification as they become available without disrupting working applications.