URI persistence policy

When information is made available on the Web, it is important for the integrity of the Web, and the society based upon it, that the URIs used to reference information be used well into the future, and that the information persist as identified.

To this end, the World Wide Web Consortium makes the following pledge: that as far as possible, for resources on the www.w3.org website which are declared (see below) to be persistent.


  • Persistent resources will continue to be available throughout the life of the Consortium;
  • Where a persistent resource is modified, a change history will be archived though the archive will not necessarily be available publicly;
  • Should W3C be disbanded, then any website will be granted the right to make a copy (at a different URI) of all public persistent resources so long as they are not modified and are preserved in their entirety and made available free of charge, and provided that the same persistence policy is applied to these "historical mirrors." In such event, the original https://www.w3.org website will be handed over for management to another organization only if that organization pledges to this policy or one considered more persistent.

As of this note, persistent resources include:

  • The home page "https://www.w3.org/";
  • Those which start "https://www.w3.org/" immediately followed by four decimal digits;
  • Those which start "https://www.w3.org/TR/" immediately followed by four decimal digits;
  • Those which start with "https://www.w3.org/ns/".

No representation is made about the persistence policies for any other information on the site.

The intent is to set an example by reducing the failure of links due to clumsy management or inadequate commitment to information persistence, and to provide a stable reference base of information about W3C-related topics as a service to the community.

Tim Berners-Lee
W3C Founding Director, October 1999