An XML file is an XML (Extensible Markup Language) data file. It is formatted much like an .HTML document, but uses custom tags to define objects and the data within each object. XML files can be thought of as a text-based database.

XML file open in Microsoft XML Notepad The XML format stores data in a structure that is machine-readable and human-readable. There are a large amount of programs that can open XML files. And since they are formatted as text documents, they can be viewed and edited by basic text editors. XML files have become a standard way of storing and transferring data between programs and over the Internet. However, they can be used by many other types of programs. The XML syntax has been utilized in a large variety of file formats, such as Microsoft Office Open XML, LibreOffice OpenDocument, .XHTML, and .SVG.