Metadata ("data about data") describe properties and content of objects, for example research data. Metadata of a dataset in RADAR include descriptive metadata, which enables others to find, reference and reuse the data (e.g. title, creator, subject or identifier of a dataset). They are created by curators and subcurators. Additionally, RADAR generates technical metadata (e.g. information on volume, format and checksums) that are relevant for long-term preservation. The system automatically creates metadata for long-term preservation in accordance with the PREMIS standard, in which all events from the first upload to the creation of copies during migration to newer storage media are recorded and documented. The metadata of the datasets published with RADAR are publicly accessible. In the process of DOI assignment and registration, the metadata are automatically converted into the DataCite format. At the same time, the metadata is converted into the DublinCore format so that it can be publicly offered for harvesting via an OAI provider. The documentation of the RADAR metadata schema is available here.