MongoDB > Basics > Overview
MongoDB is an open source document-based database that is built on an architecture of documents and collections. All the data is stored as documents that comprise sets of key-value pairs. Documents are grouped inside separate collections equivalent to the tables in relational databases. The documents are stored using a json-similar rich format called BSON. MongoDB provides high performance, availability and scalability. MongoDB uses the document data model which is more flexible than the relational model since it allows for more flexible representation of complex hierarchical relationships using embedded documents. MongoDB is also designed to scale out by supporting automatic scaling using sharding and replication. MongoDB is also designed to be a general database offering many nice features such as generic secondary indexes, aggregation pipeline, and automatic failover.