You can save Microsoft Office Visio drawings as XML (Extensible Markup Language) files and open them again in Visio without any loss of information. You can also import XML files created in other applications as long as these files contain correctly constructed XML code; that is, well-formed XML code that complies with the XML for Visio Schema and the internal rules of Visio.

Three XML file formats correspond to the three main types of XML for Visio files:

• XML drawing files have the .vdx extension.
• XML template files have the .vtx extension.
• XML stencil files have the .vsx extension.

These files function in the same manner as their binary counterparts (.vsd, .vst, and .vss, respectively).

You can specify that all Visio drawings you create be saved as XML files by default.

Because the Visio XML files can be modified in other applications, the XML, while still valid, may not conform to the Visio XML file format. If you open or save an XML for Visio file that contains errors, Visio attempts to open or save as much as possible of the modified XML file. You can specify whether Visio displays warnings when you save or open an XML for Visio file that contains errors.

For more information about the details of the XML for Visio file format, search for "XML for Visio" on the Microsoft Developer Network (MSDN). For best results, search for the exact phrase using Advanced Search.