In 2013/14 the Deutsche Digitale Bibliothek (DDB) switched its data model from the CIDOC conceptual reference model to the Europeana Data Model (EDM). This decision was taken on the background of two major mandates the DDB has to fulfill: The DDB is as a portal and a platform providing access to digital objects from German cultural heritage and research institutions. On the other hand the DDB aims to become the German aggregator for Europeana. Using EDM as the internal DDB data model was approved as the most reasonable solution to meet these challenges. The DDB uses the model for all portal functions that require semantic links between metadata (search facets, hierarchies, links between authority files and digital objects). The application of EDM for the DDB portal raised some difficulties since not all necessary classes and properties were entirely implemented in Europeana-EDM at that time. Therefore, a DDB-EDM application profile was developed. The DDB publishes metadata under the CC0 Public Domain Dedication license in EDM-RDF/XML via an OAI-PMH interface to serve Europeana and also via an Application Programming Interface (API) for external users to develop new applications on the basis of metadata harmonized by the DDB.