MetaStore is a metadata repository for managing metadata documents. It supports communities in storing metadata documents in a predefined schema. It is therefore an important building block for more precise automated evaluation and/or retrieval of digital objects. With the help of the metadata documents, digital objects can also be evaluated/compared according to content-related aspects. XML and JSON are very common as data formats for such machine-interpretable documents. However, they are only meaningful if they adhere to a certain structure and are correctly filled in. MetaStore supports the use of XML and JSON schema as the definition for the document structure. It allows you to register your own and/or existing schemas in these two formats to ensure that the documents have the appropriate structure. When ingesting metadata documents, the structure is checked and invalid documents are rejected. All valid documents are assigned a persistent identifier and can be automatically indexed for search. Public documents can be harvested via a standardized protocol (OAI-PMH). The supplied web interface also provides a low-threshold entry point for managing documents and also allows documents to be created/edited without additional tools. This work has been supported by the research program ‘Engineering Digital Futures’ of the Helmholtz Association of German Research Centers and the Helmholtz Metadata Collaboration Platform.