WDDX was created by Simeon Simeonov of Allaire Corporation in 1998,[1] initially for the ColdFusion server environment.
WDDX can also be used to serialize data structures to storage (file system or database).
Many applications use WDDX to pass complex data to browsers where it can be manipulated with JavaScript, as an alternative to JSON.
Outside ColdFusion, libraries exist to read or write this format, Ruby,[6] Python,[7] PHP, Java, C++, .NET,[8] Actionscript,[9] lisp, Haskell, Perl.
PHP used to offer a comprehensive support for WDDX, which could be used as a format to store session information[10] until the version 7.4.