Persistent Uniform Resource Locator, a URL maintained by a PURL service that redirects (typically via HTTP 302) to the current location of the named resource, allowing the persistent URL to remain stable as the underlying resource location changes.

ByCASRAI Editorial Board

· Last updated 10 Jul 2026

Examples

Worked examples

Is an instance
https://w3id.org/dpv (a W3C Permanent Identifier Community Group PURL for the Data Privacy Vocabulary).
Is an instance
An archive.org-style PURL redirecting an old URL to its current location.

Counter-examples

Looks similar, but isn't

Not an instance
A bit.ly shortener link is not a PURL, even though it redirects, because it is not run as a curated persistent-naming service.
Not an instance
A canonical-link <link rel='canonical'> tag is not a PURL.

Editorial commentary

PURLs were introduced by OCLC in 1995 to address the link-rot problem on the early Web. A PURL service operates a redirect table; users cite the PURL, and the maintainer keeps the redirect target current. The original OCLC PURL service was retired in 2016, and the registered PURLs were migrated. Today PURL-style services are run by archive.org’s Internet Archive PURL, w3id.org (W3C Permanent Identifier Community Group), and various domain-specific resolvers.

References

Shafer K., Weibel S., Jul E., Fausey J., 'Introduction to Persistent Uniform Resource Locators', OCLC, 1996.

Also known as

Persistent Uniform Resource Locator · Persistent URL

Machine-readable encodings

Use in your systems

JATS XML <role> element

xml

<role vocab="credit"
      vocab-identifier="https://casrai.org/dictionary/"
      vocab-term="PURL"
      vocab-term-identifier="https://casrai.org/dictionary/term/purl" />

Schema.org DefinedTerm (JSON-LD)

json

{
  "@context": "https://schema.org",
  "@type": "DefinedTerm",
  "@id": "https://casrai.org/dictionary/term/purl",
  "name": "PURL",
  "identifier": "https://casrai.org/dictionary/term/purl",
  "description": "Persistent Uniform Resource Locator, a URL maintained by a PURL service that redirects (typically via HTTP 302) to the current location of the named resource, allowing the persistent URL to remain stable as the underlying resource location changes.",
  "inDefinedTermSet": "https://casrai.org/dictionary/domain/persistent-identifiers#set",
  "url": "https://casrai.org/dictionary/term/purl",
  "sameAs": [
    "Persistent Uniform Resource Locator",
    "Persistent URL"
  ],
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "publisher": {
    "@id": "https://casrai.org/#organization"
  },
  "dateModified": "2026-07-10T02:06:20",
  "inLanguage": "en"
}

Referenced across the research world

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