FAIRCORE4EOSC focuses on the development and realisation of EOSC-Core components supporting a FAIR EOSC, addressing gaps identified in the SRIA. Leveraging existing technologies and services, the project will develop nine new EOSC-Core components aimed to improve the discoverability and interoperability of an increased amount of research outputs. FAIRCORE4EOSC will also contribute to the EOSC Interoperability Framework by establishing new guidelines on the new EOSC-Core components. The new components will be crucial to support the FAIR research life cycle. Five user-centric case studies (climate change, social sciences and humanities, mathematics, national research information systems, research data management communities) will drive the development and testing of the new components ensuring they are tailored to the user needs (co-design). All the selected case studies share similar challenges that are common to many other stakeholder groups: research communities at European and national level have datasets that currently cannot be found in the EOSC; they use Digital Object Identifiers (DOIs) but they are lacking PIDs for different levels of aggregation; they use community specific services to manage metadata that make cross-discipline reuse and interoperability complex. The user stories and best practices drawn by the case studies will be used to foster uptake of the new components beyond the project partners. The 22 complementary partners of the FAIRCORE4EOSC consortium have long-lasting experience in the provision and development of research data services, persistent identifiers, metadata and semantic registries, services and tools to archive and reference research software. The partners have also significantly contributed to the EOSC SRIA and are active members of the EOSC Association Task Forces (TFs) providing the project a unique insight and capacity to boost the development of the Web of FAIR Data and Related Services.