RELAX NG Specification (errata), OASIS Committee Specification, 3 December 2001. Can be used as a library for validation and for accessing the schema.

Provides many other features useful for processing data described by a RELAX NG schema.

It is based on an XSLT stylesheet written by Eric van der Vlist. Can generate a collection of Java classes from a RELAX NG schema along with code to create instances of those classes from XML and vice-versa. By embedding code fragments in the grammar like yacc or Java CC, you can take appropriate actions while parsing valid XML documents against the grammar. Allows any RELAX NG schema to be used to guide editing.

ISO/IEC 19757-2: Amd1 Document Schema Definition Language (DSDL) -- Part 2: Regular-grammar-based validation -- RELAX NG -- Amendment 1: Compact Syntax.

ISO version of the RELAX NG Compact Syntax; RELAX NG Compact Syntax; the technical content of this is identical to the OASIS Committee Specification, but there are editorial changes to satisfy ISO rules.

Trang aims to produce human-understandable schemas; it tries to preserve all aspects of the input schema that may be significant to a human reader, including the definitions, the way the schema is divided into files, annotations and comments.

Sun MSV Schematron add-on, allows a document to be validated against a RELAX NG grammar and also against Schematron constraints embedded as annotations in the RELAX NG. Trang can also infer a schema from one or more example XML documents.

RELAX NG Compact Syntax, OASIS Committee Specification, 21 November 2002. Recent versions of libxml2 (at least 2.5.5) support RELAX NG validation. Libxml2 is included in most modern Linux distributions.

Definitive specification for the compact syntax in terms of the XML syntax. Can be used as a library for validation with any SAX2 parser.

The RELAX NG specifications have been developed within OASIS by the RELAX NG Technical Committeee.