Open, persistent identifiers for managing Web resources

PURLs are Web addresses or Uniform Resource Locators (URLs) that act as permanent identifiers in the face of a dynamic and changing Web infrastructure. Instead of resolving directly to Web resources (documents, data, services, people, etc.) PURLs provide a level of indirection that allows the underlying Web addresses of resources to change over time without negatively affecting systems that depend on them. This capability provides continuity of references to network resources that may migrate from machine to machine for business, social or technical reasons.

This site is a home for the PURLs software.  For a partial list of hosted PURL services, see PURLs in the Wild.


  • PURL Development Shifting to 3 Round Stones Further development of the PURL software is shifting to 3 Round Stones.  3 Round Stones has taken over production PURL services previously offered by Talis Group Ltd's US subsidiary, Talis Inc.  The community services for PURLs including the Web site and discussion list remain unaffected.  3 Round Stones intends to continue to develop the PURL software to include IPv6 support in the coming months.
    Posted Jun 10, 2011, 10:19 AM by David Wood
  • PURL Federation Beta 4 available A Beta release of the PURL Federation codebase is now available.  See the Downloads area or the current subversion checkout for the code.  Have fun and don't forget to give us feedback!
    Posted Jul 29, 2010, 7:46 AM by David Wood
  • PURL Federation development underway NCBO and Zepheira announce development of a PURL Federation on 22 March 2010.The National Center for Biomedical Ontology and Zepheira are pleased to announce work on a PURL Federation.  A PURL Federation will allow multiple PURL service operators to cooperate in PURL resolutions, covering for each other in the case of service outages and allowing the persistent resolution of PURLs as funding levels and organizational details change with time.PURL Federations are intended to enhance the ability of Semantic Web and Linked Data communities to ensure the persistence of their identifiers.Prototypes of the PURL Federation code will be released occasionally in the coming months, with an Alpha version to be released in the Summer of 2010.  Further announcements ...
    Posted Jul 29, 2010, 7:41 AM by David Wood
  • PURLZ Server version 1.6.3 released PURLZ Server version 1.6.3 significantly increases the efficiency of PURL validations. See the Downloads area to get your copy now.   Version 1.6.3 is the latest stable release as of 9 March 2010.
    Posted Jul 29, 2010, 7:30 AM by David Wood
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