High Quality Content by WIKIPEDIA articles! In computing, RELAX NG (REgular LAnguage for XML Next Generation) is a schema language for XML, based on Murata Makoto`s RELAX and James Clark`s TREX. A RELAX NG schema specifies a pattern for the structure and content of an XML document. A RELAX NG schema is itself an XML document; however, RELAX NG also offers a popular compact, non-XML syntax. Compared to other popular schema languages, RELAX NG is relatively simple. It was defined by a committee specification of the OASIS RELAX NG technical committee in 2001 and 2002, and also by part two of the international standard ISO/IEC 19757: Document Schema Definition Languages (DSDL). ISO/IEC 19757-2 was developed by ISO/IEC JTC1/SC34 (ISO/IEC Joint Technical Committee 1, Subcommittee 34 - Document description and processing languages) and published in its first version in 2003.