BY-COVID Work Package 3 is focused on services for the discovery and integration of COVID-19 data by delivering a flexible, tiered metadata discovery system across different domains, metadata standards, and maturity/robustness levels of data sources. This will enable the linking of FAIR data and metadata on SARS-CoV-2 and COVID-19, on other related viruses and diseases, and on socio-economic consequences, across research fields, from omics, clinical, and epidemiological research, to social sciences and humanities. Building on the metadata format developed in D3.1, in a series of work package meetings and a workshop, with participation from all other work packages, we have developed tools (example Validator), workflows (Semi-automated transfer of resource metadata from FAIRsharing to Covid-19 portal), and documentation and training (Training: Discoverability hackathon) to support the efficient integration of additional resources from a broad range of domains into the COVID-19 Data Portal as well as improved the end user facing COVID-19 Data Portal itself (Global search). This work establishes the basis for the further development of the COVID-19 Data Portal metadata discovery, and provides a path for integration of metadata from multi-domain partners in BY-COVID, as well as our ISIDORe sibling project, and other relevant external resources. To ensure smooth integration of partner provided metadata, we anticipate re-running our “Discoverability hackathon” in the future and will continue to evolve our metadata format and presentation of the COVID-19 Data Portal. We anticipate significant development and metadata modelling work for the use-case driven support of complex data sources in close collaboration with WPs 2, 4 and 5.