Invisible XML

Invisible XML is a language for describing the implicit structure of data, and a set of technologies for making that structure explicit as XML markup. It allows you to write a declarative description of the format of some text and then leverage that format to represent the text as structured information.


Invisible XML (ixml) 1.0 was published on 10 June, 2022. The grammar of Invisible XML is defined with Invisible XML. The ixml grammar for ixml is available in ixml format or in xml format. Invisible XML was developed by the Invisible Markup Community Group at the W3C.



Test suite

The ixml GitHub repository includes a comprehensive test suite. It is also available as a browsable catalog.


The XML versions of Invisible XML grammars conform to the RELAX NG schemas provided.

Example grammars

A selection of sample grammars are available including:

In addition, Gunther Rademacher’s grammar converter will attempt to output Invisible XML.

Other Tools


There are a few additional papers and presentations on the development of Invisible XML