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About is a service that helps anyone who needs to cite to the web create links to their references that will never break. prevents link rot.

What is

When a user creates a link, archives the referenced content and generates a link to an archived record of the page. Regardless of what may happen to the original source, the archived record will always be available through the link. To learn more about how works, please take a look at our user guide. is developed and maintained by the Harvard Law School Library in conjunction with university law libraries across the country and other organizations in the “forever” business.

Why use

In a sample of several legal journals, approximately 70% of all links in citations published between 1999 and 2011 no longer point to the same material. Broken links in journal articles undermine the citation-based system of legal scholarship by obscuring the evidence underlying authors’ ideas.

As Internet usage becomes more widespread and web citations in scholarship become more common, the problem of link rot will become increasingly important.

Using ensures that material cited by authors will always be accessible to readers, preserving the foundation of scholarship and reference online.

How works

Users go to the website and input a URL. downloads the material at that URL and gives back a new URL (a “ link”) that can then be inserted in a paper, article, blog or whatever the author needs.

Readers who encounter links can click on them like ordinary URLs. This takes them to the site where they are presented with a page that has links both to the original web source (along with some information, including the date of the link’s creation) and to the archived version stored by relies on a distributed set of journals and libraries for administration. Journals work with authors to create archives and libraries provide guidance and oversight to journals.


Academic institutions and courts can become registrars of for free, and can provide accounts to their users for free as well.

Organizations (such as law firms, publishers, non-profits and others) or individuals not associated with an academic institution or court are both able to use Perma via paid subscription:

  • Organizations can administer unlimited Perma accounts for their users for a monthly flat group rate. These registrar accounts also include collaboration tools and administrative controls.
  • Individuals not affiliated with a Registrar can access Perma via tiered subscriptions that fit their particular needs, or make an ad hoc purchase of links.

Subscription status does not affect the preservation, access, or visibility of already-made links, just the number of Perma Links a user can create in a given month.


Organizations that do not qualify for free usage can contact our team to learn about creating a subscription for providing to their users. Pricing is based on the number of users in an organization and the expected volume of link creation.

For individuals who are not affiliated with a Registrar, there are two options for purchasing additional Perma Links beyond their trial: an ongoing subscription that releases a set number of links to be created each month, and ad hoc purchasing of a batch of links. Pricing details can be found on your dashboard or in our user guide.

Library-strength reliability was built by Harvard’s Library Innovation Lab and is backed by the power of libraries. We’re both in the forever business: libraries already look after physical and digital materials — now we can do the same for links.

Try for libraries

If you’re a librarian or are affiliated with a library, we can make using free and simple for you and the scholars that depend on you. We’ve answered many common questions and prepared a special library signup at the link below.