Welcome to episode 4, discussing the architectural developments in EHDEN, within Work Package 4, co-led by Julia Kurps, Team Lead of the Real World Data Team, The Hyve, and Michel Van Speybroeck, Director, Data Sciences, Janssen. We explore the considerable opportunity, challenges and innovation required to develop a central Portal for EHDEN than can support research and collaboration between Data Partners and researchers. Julia and Michel discuss their own unique backgrounds and careers, and then we investigate the work they are co-leading with WP4 colleagues across diverse public and private organisations to build the EHDEN Portal, central to both the sustainability and the use of EHDEN in conducting open science research using OMOP-mapped data at scale for network studies.  In the main body of the discussion, Julia and Michel outline what EHDEN is working to achieve with the Portal build, encompassing discoverability via a Catalogue through to standardised analytics (in collaboration with OHDSI)  and an Evidence Hub. Furthermore, EHDEN is extending the OHDSI analytical tools, as well as supporting methodological aspects within an integrated framework, while incorporating processes, procedures and governance. Overall, this is within a wider ecosystem of Data Partners and researchers, inclusive of the Portal, but also training support via, e.g., the EHDEN Academy. Innovation, described in the discussion, has to be sustainable, inclusive of a wider and growing community of those who can conduct open science research themselves, with diverse use cases, such as in Health Technology Assessment, Pharmaceuticals, or with Data Partners, all who have specific expectations, requiring a balance within a technical architecture. The views expressed by the participants are personal and not necessarily reflective of their organisations.