XML – Extensible Markup Language

The Extensible Markup Language (XML) is a markup language used to display hierarchically structured data in the form of text files. Among other things, the Extensible Markup Language is used for platform- and implementation-independent exchange of data between computer systems, and in particular over the internet.

The XML specification published by the World Wide Web Consortium (W3C) (Recommendation, first edition 10 February 1998, current fifth edition published 26 November 2008), defines a metalanguage which forms a basis upon which application-specific languages can be defined using structural and content restrictions. These restrictions are expressed through schema languages such as DTD or X M L Schema.

Example X M L languages include RSS, MathML, GraphML, XHTML, XAML, scalable vector graphics (SVG), GPX, and also X M L Schema. An X M L document consists of text characters (encoded in ASCII in the simplest cases) which means that it is human-readable. By definition, an X M L file does not include binary data.