Sharing machine actionable metadata increases the discoverability of scientific studies and promotes archival work. Metadata harvesting is a way to share such metadata on a large scale and to a wide group of interested parties and is typically achieved automatically with minimal human interaction. CESSDA is developing a metadata aggregator service which will expose the metadata records in CESSDA Data Catalogue for re-harvesting via OAI-PMH. Together with the Catalogue, the aggregator will provide a comprehensive discovery solution for CESSDA Service Providers' metadata records. The aggregator will make records available in DDI-C, OAI-DC and Datacite. Initial targets are B2Find, OpenAIRE and Triple catalogues. The aggregator features OAI-sets to group records based on their originating archive and provides provenance information to track the origin of each record. CESSDA and FSD partnered up to develop the aggregator system. FSD had prior knowledge of OAI-PMH and machine actionable metadata standards, in fact the aggregator software is based on FSD's Kuha2. While FSD is responsible of providing the development work, CESSDA is committed to operating the software and maintaining its runtime environment. The presentation will outline the purpose of the software, main functionality, status of the project and immediate plans. Recorded version of this talk: https://youtu.be/1d8Pqe_Lz-I