Crossmark guide

These are the steps members need to take to get started with Crossmark:

1. Sign up

Drop an email to to let us know that you want to get started with Crossmark.

2. Create a Crossmark Policy Page and assign it a DOI

Create a page on your website explaining that you are participating in the Crossmark service and have committed to maintaining version of record copies of content that display the Crossmark button. This page should be registered and have a DOI to enable persistent linking. It should explain your policies on corrections, retractions, withdrawals and other updates, and may contain definitions and explanations of any additional custom metadata fields that are being used. The page could also include links to other relevant policies such as author submission guidelines, peer review guidelines, etc.

3. Deposit Crossmark Metadata

Crossmark metadata should be deposited as part of your regular Crossref metadata deposit, but can also be deposited as stand-alone data for populating backfiles.

The minimum required Crossmark metadata comprises:

  • The DOI of the content the Crossmark is being applied to
  • The DOI for the publisher’s Crossmark Policy Page
  • The DOI of any piece of content that is being updated

4. Provide DOIs for items being corrected or updated**

“Updates” should only be deposited for changes that are likely to affect “the interpretation or crediting of the work.” In other words, updates should only be deposited for editorially significant changes. Updates should not be deposited for minor changes such as spelling corrections, formatting changes, etc.

There are 12 defined types of accepted “update” within Crossmark. The values for these are:

  • addendum
  • clarification
  • correction
  • corrigendum
  • erratum
  • expression_of_concern
  • new_edition
  • new_version
  • partial_retraction
  • removal
  • retraction
  • withdrawal

If an update does not fall into one of these categories it should instead be placed in the “more information” section of the pop-up box by being deposited as an assertion.

5. Record the DOI in HTML metadata

You should ensure that the DOI is embedded in the head of the HTML metadata for all content to which Crossmark buttons are being applied as follows:

<meta name=”dc.identifier” content=”doi:10.5555/12345678”/>

6. Apply the Crossmark button to your HTML pages

Crossref supplies a templated HTML/JavaScript code widget which will embed the Crossmark button and functionality into your web pages. The latest version of the widget (v2.0) is below. Do ensure you are using the latest version and that it points to our production server.

v2.0 is the current version. This update brings a responsive Crossmark box and new button designs. Please use the widget as specified below and do not alter the script or host the button locally.

<!-- Start Crossmark Snippet v2.0 -->

<script src=""></script>
 <a data-target="crossmark"><img src="" width="150" /></a>

<!-- End Crossmark Snippet -->

There are a number of variations of the Crossmark button available so that you can choose one that fits well on your site. Further detail is available in our documentation.

Notes on previous versions:

  • v1.5 is no longer supported as of March 2017. This implements HTTPS, and can be used both on HTTP and HTTPS sites. You should always access the widget files with HTTPS even if your site is HTTP.
  • v1.4 and lower are now deprecated. This and older versions of the widget will continue to work, but we recommend that you use the most recent version.

7. Apply the Crossmark button and metadata to your PDF content

Crossmark metadata needs to be added to your PDF content. Minimally, this metadata must include the DOI of the content and the optional Crossmark domain(s).

You may wish to use our open source tool called “pdfmark” for embedding metadata in PDF files.

We have also created “pdfstamp”, an open-source command line tool that makes it possible to add an image or “stamp” to any location on a PDF and to link that image to a chosen URL.

The link structure for Crossmark links from PDFs looks like this:

The domain argument tells the Crossmark system what kind of static content the link is coming from. This will change for different static formats (e.g. epub, etc.)

The date_stamp argument tells the Crossmark system the date on which a last “Major Version” of the PDF was generated. In the vast majority of the cases, this will just be the date on which the article was published. However, in cases where a publisher makes significant corrections to a PDF in-situ (they do not issue a separate correction or new version of the document with a new DOI) then the date_stamp should reflect when the PDF was regenerated with the corrections. The system will then use the date_stamp in order to tell whether the researcher needs to be alerted to updates or not. The date_stamp argument should be recorded in the form yyyy-mm-dd. (ISO 8601)

Last Updated: 2017 January 19 by Kirsty Meddings