FAIRCORE4EOSC Deliverable D3.1 EOSC Federated Search Service and PID Graph Service

This report provides a comprehensive overview of the technical developments carried out in the FAIRCORE4EOSC project under Work Package 3 (WP3), focusing on the design, implementation, and production release of two key components: the Research Discovery Graph (RDGraph) and the PID Graph. The RDGraph is an EOSC Federated Search Service that enables cross-repository and cross-community discovery of research entities—including publications, data, software, and activities—by leveraging graph-based models and natural language processing. It extends the EOSC Catalogue with support for additional entities such as Research Activity Identifiers (RAiDs) and offers multiple access methods including user-friendly interfaces, APIs, and open data dumps to ensure interoperability and reuse. The PIDGraph aggregates metadata and persistent identifier (PID) relationships from authoritative sources such as ORCID, ROR, Crossref, and DataCite. It is designed to support third-party integration and data consumption through APIs and data files, and provides a Data Usage Statistics Service that aligns with the EOSC’s vision of a connected, open research infrastructure. The development of both components followed an agile and iterative approach, emphasizing early prototyping, modular design, and continuous stakeholder engagement. Regular interactions with use case leaders and demonstrators ensured that the systems evolved in line with real-world needs, enabling timely beta releases and refinements based on user feedback. Active engagement and outreach efforts played a critical role in the success of both components. Both components were showcased through webinars, conferences, and dedicated workshops with demonstrators, case studies, and end users. Regarding sustainability, RDGraph will continue to be supported and maintained within the OpenAIRE infrastructure, ensuring long-term integration into EOSC services. PIDGraph will remain openly accessible and actively developed by DataCite, with multiple access options including the DataCite Commons portal, APIs, and downloadable datasets. Together, RDGraph and PIDGraph represent significant contributions to the European Open Science Cloud, advancing discoverability, interoperability, and reuse of research outputs across disciplines and communities.