MongoDB is a non-relational database that solves the interoperability puzzle in healthcare by providing document flexibility, scalability, performance, and security features. Its document data model allows for managing complex clinical data with varying levels of detail and granularity, while its horizontal scaling feature enables easy distribution of large datasets across multiple servers and cloud providers. MongoDB's advanced querying capabilities and robust security features, including fine-grained access control and auditing, make it an ideal solution for building a truly interoperable data repository. With its unique approach to data storage and retrieval, MongoDB integrates seamlessly with clinical data repository vendors and enables healthcare providers to own the data layer and leverage any usages from stored data.