Building Better Metadata: CRAFT-OA Contributions Arriving in OJS 3.6

written by Antti-Jussi Nygård

As the CRAFT-OA project approaches its conclusion at the end of 2025, final core contributions are being integrated into the next major release of Open Journal Systems (OJS). OJS 3.6 will include two significant developments produced within the project: new metadata features led by the Federation of Finnish Learned Societies (TSV) and GDPR-compliant reviewer invitation workflows implemented by the TIB – Leibniz Information Centre for Science and Technology and University Library. In addition to these core contributions to OJS itself, TIB has also developed an enhanced metadata validation mechanism, the Publication Validator plugin, which improves metadata completeness.

Together, these efforts strengthen the OJS support for high-quality metadata, privacy-aware editorial processes, and more reliable publication workflows.

The work was carried out in close collaboration with the Public Knowledge Project (PKP), the main developer of OJS. Because PKP maintains a family of related applications, Open Monograph Press (OMP) for book publishing and Open Preprint Systems (OPS) for preprints, the improvements developed within CRAFT-OA will become available across all three platforms.

This blog post takes a closer look at the metadata improvements developed by TSV and how they will appear in OJS 3.6.

A strengthened foundation for structured metadata

Reliable, machine-readable metadata is essential for discoverability and for connecting publications with research infrastructures. Publishing platforms need clear, consistent metadata to operate well with services such as Crossref, DataCite, ORCID and OpenAIRE.

Earlier versions of OJS already provided a solid metadata model, but some underlying conventions limited how effectively journals could represent contributors, vocabularies and related datasets. The CRAFT-OA development work for OJS 3.6 addresses these specific issues and adds more flexibility and structure where it is most needed.

Together, these improvements bring OJS more closely in line with contemporary metadata practices and offer Diamond Open Access journals better tools for producing consistent, standards-aligned metadata.

A structured and machine-readable contributor role taxonomy

A central change in OJS 3.6 is the introduction of a separate contributor role taxonomy. In earlier versions, roles such as “Author” or “Translator” came from user groups that were also used for defining user permissions in the system, and these roles did not have machine-readable identifiers for telling the roles apart. This dual use also led to confusion for users and made metadata harder to manage consistently.

In OJS 3.6, contributor roles are no longer tied to user groups but are defined in a dedicated taxonomy used solely for metadata. Each role has a persistent identifier, ensuring contributor information is consistent, machine-readable, and easier for external services to interpret. It also enables OJS themes to display contributor types in different ways. For example, authors, translators or even roles like illustrators can be shown separately on landing pages, giving journals more control over visual representation of articles.

Recognising organizations and collective authorship

Journals publish work attributed not only to individuals but also to institutions or editorial groups. Earlier versions of OJS had no proper way to represent organizational contributors, so journals often entered organization names into fields intended for personal names. This resulted in inaccurate metadata, made it impossible to include identifiers such as ROR IDs, and reduced the ability of external services to correctly interpret or link organizational authorship.

OJS 3.6 resolves this by supporting three contributor types: persons, organizations and anonymous contributors. Organizational contributors can include persistent identifiers such as ROR IDs, improving compatibility with external services and making institutional authorship both visible and machine-readable.

Integrating CRediT attribution into the core workflow

Transparent contributor information is increasingly expected by funders, publishers, and indexing services. The CRediT taxonomy provides a structured vocabulary for describing specific contributions in detail, such as Conceptualization, Data Curation or Writing. Until now, CRediT support in OJS was available only through a plugin.

As part of CRAFT-OA’s work, OJS 3.6 integrates CRediT directly into the core. Editors can record one or more CRediT roles for each contributor, and the roles are included in metadata exports.

New contributor metadata allows journals to define contributor types, add custom contributor roles and make use of CRediT roles.

Making research data visible with structured citations

Research data plays an increasingly central role in scholarly communication. However, OJS previously had no native way to record structured dataset references. Journals were limited to mentioning datasets in free-text fields, which made it impossible for services to identify and index data-publication relationships.

OJS 3.6 introduces support for structured data citations, allowing links between publications and research datasets to be recorded and exported to services like Crossref and DataCite.

The implementation captures all key components required for standardized data–publication relationships, including dataset identifiers (such as DOIs), identifier types, relationship types, dataset creators, and brief descriptive information.

OJS 3.6 will support structured data citations, enabling journals to link articles to research data published in repositories like Zenodo.

Controlled vocabularies for higher-quality metadata

Support for controlled vocabularies was introduced in OJS 3.5: journal editors can now choose metadata terms (e.g., keywords or subject classifications) that include both a label and a persistent identifier/URI, rather than relying solely on free-text entries. This change enables linking to authoritative vocabularies, for example, national thesauri, and supports external vocabularies through a plugin architecture.

Although originally planned for OJS 3.6, the feature was implemented early in 3.5. OJS 3.6 does not change this functionality and controlled-vocabulary support is now part of the core metadata infrastructure.

Contributing to a sustainable OJS ecosystem

With the delivery of the OJS 3.6 developments, CRAFT-OA completes its contribution to improving and extending PKP’s publishing platform. Earlier work delivered in OJS 3.5 introduced major multilingualism improvements and a new invitation-based user and role management process. The developments included in the OJS 3.6 build on this foundation, adding enhancements to metadata quality, contributor representation and support for data citations.

Although the CRAFT-OA project concludes at the end of 2025, the features it delivers will continue to evolve within the PKP community. Their integration across OJS, OMP, and OPS ensures that the project’s impact extends beyond its duration, supporting multilingual Diamond Open Access publishing for years to come.