XML Schema Working Group Charter

The mission of the XML Schema Working Group, part of the Extensible Markup Language (XML) Activity, is to maintain and enhance the XML Schema Definition Language, an XML vocabulary for defining document classes by specifying structural and non-structural constraints on documents. XML Schema is similar to, but more expressive than, the notation given in XML 1.0 and SGML for document type definitions.

Join the XML Schema Working Group.

End date 31 January 2013 (or earlier)
Confidentiality Proceedings are Member-only
Initial Chair David Ezell
Initial Team Contacts
(FTE %: 30)
Michael Sperberg-McQueen, Liam Quin
Usual Meeting Schedule Telcons: Weekly
Ftf: annually plus TPAC


The XML Schema Working Group is in the process of finishing publication and review of an updated version of XML Schema Definition Language, called XSD 1.1. This new version has many new features of importance to users in industry and in other standards efforts that require the specification of XML languages. The primary focus of the Working Group is to move this new version toward Recommendation Status and to maintain it and older versions of XSD, including XML Schema 1.0.

Success Criteria

The Working Group expects to demonstrate at least two interoperable implementations of each new feature of XSD 1.1 before requesting to advance to Proposed Recommendation.


A set of W3C Recommendations for:

Other Deliverables

The following additional items will be developed and/or maintained by the XML Schema Working Group:

  • An interoperability test suite for XSD 1.1: intended to assess the accuracy of the Candidate Recommendation, and to promote interoperability.
  • Errata list for XML Schema version 1.0 and XSD 1.1, with new editions of the 1.0 and 1.1 specification as needed. This may include a third edition of XSD 1.0.
  • A Primer to introduce people to Schema 1.1 and to give an overview of the new features.
  • Errata list for XML Schema Component Designators, with new editions of the specification as needed
  • A documented set of features and capabilities that the Working Group believes to be essential for the next generation XML Schema Definition Language
  • A Working Group note on how to implement versioning using XSD 1.1
  • A Working Group note on simplified syntax for XSD 1.1


Note: The Schema Working Group did publish Candidate Recommendation documents for Schema 1.1, but then, after making small but substantive changes as a result of comments, went back to Working Draft in December 2009. They are currently at Last Call. A relatively short second Candidate Recommendation review period is planned and, as of November 2010, the Working Group is focused on revising its test suite.

Specification FPWD LC CR PR Rec
XSD 1.1 Part 1: Structures N/A N/A April 2011 June 2011 August 2011
XSD 1.1 Part 2: Datatypes N/A N/A April 2011 June 2011 August 2011
XSD: Component Designators N/A N/A N/A May 2011 July 2011

Timeline View Summary

It is expected that the XSD 1.1 Primer will be produced as a Working Group Note during 2011.


The expiration date of this charter shall be 30 January 2012.


W3C Groups

XML has become a strategic technology in W3C and elsewhere. The deliverables of the XML Schema Working Group must satisfy the dependencies from other W3C Working Groups. Some dependencies to and from other W3C Working Groups will require close cooperation during the development process; history has shown that the requirements posed for the Schema work by these Working Groups may change substantially during the development process, which means the interdependency of the Schema work with these Working Groups must be managed actively:


To be successful, the XML Schema Working Group is expected to have 5 or more active participants for its duration. Effective participation to XML Schema Working Group is expected to consume half of a work day per week for each participant; more for editors. The XML Schema Working Group will allocate also the necessary resources for building Test Suites for each specification.

Participants are reminded of the Good Standing requirements of the W3C Process.


This group primarily conducts its work on the Member-only mailing list w3c-xml-schema-ig@w3.org (archive), as well as various other lists: w3c-xml-schema-wg@w3.org (archive). Public feedback for publication happens through www-xml-schema-comments@w3.org (archive), and general questions about the language come through xmlschema-dev@w3.org (archive).

Information about the group (deliverables, participants, face-to-face meetings, teleconferences, etc.) is available from the XML Schema Working Group home page.

Patent Policy

This Working Group operates under the W3C Patent Policy (5 February 2004 Version). To promote the widest adoption of Web standards, W3C seeks to issue Recommendations that can be implemented, according to this policy, on a Royalty-Free basis.

For more information about disclosure obligations for this group, please see the W3C Patent Policy Implementation.

About this Charter

This charter for the XML Schema Working Group has been created according to section 6.2 of the Process Document. In the event of a conflict between the provisions of any charter and the W3C Process, the W3C Process shall take precedence.

Please also see the previous charter for this group.

There are no new Recommendation Track deliverables in the 2011 revision of this Charter.

Liam Quin, XML Activity Lead
Michael Sperberg McQueen, Staff Contact

$Date: 2011/03/13 18:54:38 $