Extensible Markup Language (XML) defines a set of rules for encoding documents in a format that is both human and machine readable. XML is a universal format maintained by the W3C, used for representation and transfer of structured data on the web or between different applications.
The language uses a structured representation by allowing user to create custom defined tags according to XML Document Type Definition (DTD) standards. The structure of XML document can be represented in the form of a tree known as Document Object Model (DOM).