MongoDB is a document database that provides high performance, high availability, and easy scalability. It uses a document-oriented data model where records are stored as documents (similar to JSON objects) which are organized into collections. Key features include embedding for fast reads/writes, indexing, replication for high availability, automatic sharding for scalability, and eventual consistency. Documents contain fields, embedded documents, and arrays. Queries use operators like $lt, $gte, $ne to filter results similar to SQL WHERE clauses. Records can be inserted, updated, deleted, sorted, limited, and projected. MongoDB can be backed up using mongodump which dumps collections to files that can be restored using mongorestore.