X:ID is an XML-based identification and diagnostic key software system. It allows users to create their own web-based diagnostic or identification keys and run them over locally or over the web. The XML-based format is combined with the eXtensible Style Sheet Transformation (XSLT) markup to allow developers to tailor the look of their keys.

X:ID stores and reads ASCII format files that are converted to the XID DTD by the key player. X:ID can play Lucid keys saved in the Lucid Interchange Format. This is an export option for the Lucid Builder.

The X:ID system is composed of a Editor and a Browser. The Editor is used to create and edit keys. The Browser is used to run them. X:ID is based on Open Source software. The main components are written in PHP compiled with the GD graphics library and the XSLT processor, Sablotron.

This software is available upon request. and is licensed under the Academic Free License version 1.2.