Integrated metadata catalogues and sharing metadata across all disciplines are needed to allow scientists and machines to collaborate across borders and disciplines in finding research data. The FAIRsFAIR project has been working on metadata integration pilot. The pilot includes integration of social science metadata into the generic research discovery system B2FIND which is part of the EUDAT CDI and therefore a central indexing tool for EOSC-hub. At the same time, CESSDA ERIC has been developing an open OAI-PMH API endpoint (called CESSDA Metadata Aggregator) to expose the metadata from the CESSDA Data Catalogue. Therefore, the decision was made to harvest CESSDA DDI Codebook 2.5 metadata records into B2FIND using the beta version of the Aggregator. Our presentation will describe the work done, the selections made, and the findings from this pilot. We will also discuss the benefits and challenges of harvesting metadata records from various sources, experiences on DDI, and the possible ways forward.