Join forces with world leading academic publishers for preservation

Since 2009, academic publishers and research libraries have collaborated to provide a global dark archive to ensure the long-term survival of online scholarly content.

Today, with 300 supporting libraries and 491 participating publishers, CLOCKSS operates 12 archive nodes at leading academic institutions worldwide. Together we preserve the authoritative versions of over 51 million journal articles, 400,000 books, and a growing collection of supplementary materials and metadata.

E-book library concept with laptop computer and stack of books on wooden table

Why Participate in CLOCKSS?

Of the Community, For the Community - CLOCKSS is governed by and for our stakeholders. Our Board of Directors has an equal number of librarians and publishers making decisions together about policies, procedures, priorities, and when to trigger content.

As the only dark archive that assigns a Creative Commons license to all triggered digital content, CLOCKSS benefits the greater global scholarly community by enabling permanent Open Access to abandoned and orphaned publications. As a result, recovered content becomes perpetually available to anyone with Internet access.

Standing the Test of Time - CLOCKSS employs world-class opensource digital preservation software development by Stanford University librarians. Digital content is stored in the CLOCKSS archive with no user access unless a “trigger” event occurs. To date, 66 titles
have been triggered and made available via open access.

The LOCKSS technology regularly checks the validity of stored data and repairs and preserves it for the long term.

CLOCKSS’s secure, robust, and decentralized infrastructure can withstand threats from technological, economic, environmental, and political failures. A destructive event in one location won’t jeopardize the survival of preserved digital content because the 11 other locations serve as mirror sites to back-up and repair the disrupted location’s archive.

Financially Secure and Sustainable - As an independent 501(c)(3) not-for-profit charitable organization CLOCKSS is committed to keeping fees affordable to allow libraries and publishers of all sizes and budgets to participate in CLOCKSS. Low operating costs make it possible to keep this commitment.

Publisher participation costs include an annual contribution based on publishing revenue (listed below), which covers e-journals, e-books, and any other materials you choose to archive. There is also a one-off set up free and transactional fees based on the volume of content archived with us.

To join CLOCKSS or to find out more, please contact us.

CLOCKSS 2023 fees for publishers

- Total Publishing Revenue - - Annual Contribution -
Under $250,000 $250
$250,000 - 500,000 $505
$500,000 - 1 million $1,185
$1 - 5 million $2,370
$5 - 10 million $4,745
$10 - 15 million $7,115
$15 - 20 million $9,475
$20 - 30 million $11,850
$30 - 40 million $14,215
$40 - 50 million $16,585
$50 - 200 million $17,790
Over $200 million $29,650

Modest transactional fees include:
• Front file ingest for journals is $0.25/article, with no charge for the first 100 articles. Backfiles are $0.15/article, with discounts at high volumes.
• For books, frontlist ingest is $3.00/book, with no charge for the first 10 books. Backlist books are $2.00, with discounts at high volumes.
• Archiving a new format with CLOCKSS may also include a setup fee that depends on the nature and complexity of the content.

Important Downloads

To participate in CLOCKSS or set up a webinar introduction, please contact us here, or at +1 (248) 848-7079

Academic Publishers – Value Proposition

Libraries demand it. When scholarly content transitioned to electronic delivery, academic libraries realized that they no longer hold copies of the content. These libraries do not feel secure that the content they license from publishers is guaranteed to always be accessible to the library’s users. Libraries have informed publishers that the content should be held in a trusted 3rd-party preservation archive, in order to ensure that if, for any reason, the content is no longer available online, continuous access to the content can be assured via the 3d-party archive. Today all journal publishers deposit their content in at least one preservation archive, and a growing number of scholarly book publishers do the same. In brief, preserving their content in an archive like CLOCKSS makes it easier for publishers to license their content to libraries.

CLOCKSS provides it. The CLOCKSS Archive holds a publisher’s content on twelve servers around the world, in a “dark” archive (i.e., users do not have access to the archived content, unless it is “triggered” for access, see below). Using the LOCKSS software, CLOCKSS ensures that the digital content is healthy so that if the content ever needs to be triggered for access, CLOCKSS is able to retrieve it and deliver it.

CLOCKSS is governed by the community. CLOCKSS is a free-standing charitable, non-profit organization in the U.S. Its Board of Directors is comprised of twelve leading academic libraries, and twelve leading academic publishers. The Board discusses and sets policies, practices, and prices.

CLOCKSS is supported by the community and is financially strong. CLOCKSS receives fees from over 491 publishers, and contributions from 300 libraries. CLOCKSS annual revenues are $1.7 million, with a small annual surplus. We generate a surplus so that CLOCKSS has a reserve in case of a disaster, and to give us a cushion to keep fees low in an uncertain and changing scholarly information landscape. In addition, CLOCKSS is committed to preservation over the long term, and the costs for preserving and migrating content grow over time.

CLOCKSS triggers are Open Access. In the rare cases that CLOCKSS triggers content, it is made available Open Access to everyone. CLOCKSS has triggered 66 journals, out of the more than 35,000 journals in the CLOCKSS system. Before CLOCKSS triggers content for access, it must be approved by the Board.


CLOCKSS has flexible and robust processes. CLOCKSS can access publishers’ content by harvest or FTP. The harvest method is especially helpful for capturing more elements of new dynamic and evolving forms of digital scholarship.

CLOCKSS is a partner to publishers and libraries. As a member of the scholarly publishing community the CLOCKSS Archive is a “good citizen”, providing a key infrastructure service and participating in industry initiatives.

To participate in CLOCKSS or set up a webinar introduction, please contact us here, or at +1 (248) 848-7079