Crossref was created back in 2000 by 12 forward-thinking scholarly publishers from North America and Europe, and by 2002, these members had registered 4 million DOI records. At the time of writing, we have over 23,600 members in 164 different countries. Half of our members are based in Asia, and 35% are universities or scholar-led. These members have registered over 176 million open metadata records with DOIs (as of today). What a difference 25 years makes!
In our 25th anniversary year, I thought it would be time to take a look at how we got here. And so—hold tight—we’re going to go on an adventure through space and time1, stopping every 5 years through Crossref history to check in on our members. And we’re going to see some really interesting changes over the years.
The Frankfurt Book Fair is the largest book fair in the world, and therefore a key event on our calendar. Held annually in Frankfurt, Germany, the 77th Frankfurt Book Fair (October 15–19, 2025) saw 118,000 trade visitors and 120,000 private visitors from 131 countries. The Crossref booth was located, as usual, in Hall 4.0 where all the stands with information about academic publishing can be found. Four Crossref colleagues attended the Book Fair this year, and in this blog post, you can read more about their meetings, experiences, and plans.
TL;DR. Metadata Manager will be retired at the end of 2025. Over the past four years, we have been developing a new helper tool to replace it, and that tool has now reached a stage of maturity that means we will be able to switch off Metadata Manager by the end of the year.
Our REST API makes all of the metadata we hold publicly available. It receives the majority of our API traffic, with around 1 billion hits per month. It’s one of the key ways that we fulfil our mission to make research objects easy to find, cite, link, assess, and reuse. From 1 December 2025, we will be revising the rate limits for the public and polite pools of the REST API to ensure that we can maintain a stable and reliable system, and that metadata is freely available to everyone.
Having joined the Crossref team merely a week previously, the mid-year community update on June 14th was a fantastic opportunity to learn about the Research Nexus vision. We explored its building blocks and practical implementation steps within our reach, and within our imagination of the future.
Read on (or watch the recording) for a whistlestop tour of everything – from what on Earth is Research Nexus, through to how it’s taking shape at Crossref, to how you are involved, and finally – to what concerns the community surrounding the vision and how we’re going to address that.
Summary of presentations
Click on image above to access the presentation.
The idea is simple in principle: scholarly records ought to be transparent – available to examine and learn from for all. Much of scientific production and communication these days has a heavy digital footprint so the Nexus is nothing but simply connecting the loose strands, right? Yet, as the scholarly record is a reflection of the continuous progress made by multiple actors within the context of scientific structures and processes, bringing the Nexus to life is a little short of simple.
“What we think of as metadata is expanding, and the notion of ‘record types’ is changing” – said Ginny Hendricks. A great majority of scholarly ‘objects’, whether they are data sets, research articles, monographs, or others, undergo many processes (including review, publication, licensing, correction, derivation) and influence knowledge and practice over time.
Making that progress visible and discoverable will allow for tracing the development of ideas and changes in our thinking over time. Transparency of the complete scholarly records will help to understand the impact of science funding and changing policies. It can support a more robust and comprehensive assessment of research, and contribute to improving integrity within as well as public trust in sciences.
Patricia Feeney has given us reasons for optimism in building a robust Nexus. She’s shown areas of greatest growth in metadata reported to Crossref and shared a public roadmap of types of information we’re asked to enable in the future. We’re seeing a true boom of datasets and peer review reports registrations, and the relationship metadata for our records is improving too. At the dawn of defaulting to open references, 44% of records we hold have associated references and that is growing. Provision of the newly enabled affiliation information (ROR IDs) is on the rise, as is the funder information. Some conversations and questions followed highlighting the need for further guidance in these areas.
To make a case for enriching metadata records, Martyn Rittman demonstrated examples of traceability of research influence on realities outside academia. He captured recent examples of data citations and other references present not just between scholarly papers, but also in policy documents and popular media. These allow for greater discoverability of literature – but also show the public influence and impact of the research and the work’s context in our wider society.
While Martyn shared our blue-skies aspiration to streamline Crossref’s APIs to offer insight to all these relationships with a single service, Joe Wass grounded those ambitions in the reality of technical work underway. His team’s attention is divided between three main areas. They continue to maintain and de-bug our existing infrastructure. They are developing self-service solutions for members. Finally, they are mapping and planning improved infrastructure, evaluating technology against the Research Nexus vision.
Bringing it back to the source (of metadata), Rachael Lammey offered a very practical guide to key activities enabling Research Nexus that all members can take on now. She highlighted the benefits of collecting and registering data citations, ROR IDs, and grant funding information. She went on to talk about challenges of subject classification (at a journal level) that our research and development efforts are focusing on at the moment.
Summary of discussions
Publishing has changed dramatically and our members recognise increasing opportunities for transparency of the scholarly record. Breaking the distant vision of Research Nexus down into actionable chunks made it more relatable for call participants. Many reflected on seeing their place in it properly for the first time. Yet, challenges remain and many were brought to the fore in the discussions.
The reliability and usability of the technology for registering metadata with Crossref needs to improve. We need to do better in supporting multi-language and multi-alphabet information. Not just developing systems anew, but also streamline the way content is registered and annotated, and continue to disambiguate the competing identifiers. Different record types, chiefly books, present specific challenges in this regard. Finally, making all that metadata accessible and usable is key to enabling insights from the rich data we collectively make available.
Technology is important, but won’t overcome the barriers that exist in the mindsets. Siloed thinking means that publishers may not be sensitive to benefits that improved relationship metadata could have for colleagues working on assessment, even within the same institutions. Greater guidance or best practices for new identifiers, such as ORCID, ROR, grants, would allow more publishers to get on board with the changes. Researchers often don’t help the cause either – many don’t realise the role and benefits of metadata for their work and are reluctant to provide rich information related to it, perceiving it as a bureaucratic burden.
In a nutshell, I learnt that – while the concept of Research Nexus is pretty complex – we’re all already participating in making it a reality. I’m grateful to the call participants for sharing their challenges and ideas so generously. It means we can work to address those. I’ll be sure to follow-up on requests for support and clearer guidelines about citing data, recording ROR IDs and grants information in the metadata, and we’ll engage our community on complex topics of record updates (corrections, retractions and versions). Be sure to keep in touch with the conversations on the Community Forum. I’ll see you there!
