What is a DOI?

How a DOI works

The DOI Foundation describes a DOI as a digital identifier of an object, any object, physical, digital or abstract. Every DOI has a prefix and a suffix separated by a forward slash, and the prefix always begins with 10. The prefix identifies the registrant, such as a publisher, and the suffix identifies the item. When someone resolves a DOI, the system looks up the string and redirects to the location currently registered for it, so when a publisher moves an article to a new platform it updates the record once and every citation still works. The DOI system is standardised as ISO 26324, first approved in 2010 and revised in 2022.

Who issues them

Researchers do not usually register DOIs themselves. Registration agencies do, working with publishers, universities and repositories. Crossref is the agency most scholarly publishers use for journal articles, books, conference proceedings and preprints, and its content registration service records metadata such as titles, authors, funding and references alongside each DOI. DataCite focuses on research data, software and other outputs held in repositories. When a paper is accepted or a dataset is deposited, the publisher or repository mints the DOI, and it is typically displayed on the article page and in its citation.

DOI, URL and ISBN are not interchangeable

A URL says where something is today; a DOI says what it is and finds where it is. That difference is why reference styles increasingly prefer DOIs to plain web links. An ISBN identifies a specific edition of a book for ordering and cataloguing, and does not resolve to anything on its own. A book or chapter can carry both an ISBN and a DOI. On a research poster, use a DOI whenever the cited item has one, and a URL only for material that does not.

Using DOIs on a poster

Two places benefit. In the reference list, adding the DOI to each entry lets a reader find the source quickly, and it is shorter than a full URL. Under the title or beside the QR code, the DOI of the full paper, preprint or dataset gives visitors a permanent way back to the work after the session. Print it as a link, https://doi.org/ followed by the DOI, which works when typed into a browser. If the paper is not yet published, a preprint server or a data repository can provide a DOI now, and the published article will later get its own. A short DOI link is also easier to read aloud in a conversation at the board than a long repository address.

Common mistakes

Printing the publisher's article URL instead of the DOI means the link can break when the platform changes. Copying a DOI with a trailing full stop or a line break inside it produces a string that will not resolve. Citing the DOI of a preprint when the peer reviewed version exists sends readers to an older version. Inventing a DOI format for an item that has none misleads. And many posters include a QR code to a personal page that disappears when the author changes institutions, where a DOI would have lasted. Another is linking to a DOI that has been registered but not yet activated, which happens when a paper is still in production; resolve it yourself on the day of printing.

Where it shows up in the poster builder

There is no dedicated DOI field on any of the forty layouts. A DOI goes in the reference list, which is numbered and present on 34 layouts, in a section's text, or in the QR slot, found on 37 layouts, where a link or text typed in is encoded. When the brief contains no citations, the generator still fills the required reference list with plausible looking entries, so replace every reference, and add real DOIs, before printing. Check each DOI by resolving it at doi.org, since a mistyped character is invisible on the board.

Questions people ask