The ExPaNDS project aims at deploying into EOSC data catalogues and data analysis services. This document describes the proposed architecture for these services and how they are planned to integrate into EOSC. The first part elaborates on our plan to abstract the data and analysis services with common APIs in order to make them available to portals and processing pipelines without knowing where the actual facility data, analysis stacks and ICT infrastructure resides. Then, as this is one of ExPaNDS high level objectives, the document describes the relationship between services provided by ExPaNDS RIs and the EOSC as well as their interdependencies.