MongoDB is a document database that provides high performance, high availability, and easy scalability.
- Documents (objects) map nicely to programming language data types.
- Embedded documents and arrays reduce need for joins.
- Dynamic schema makes polymorphism easier.
- Embedding makes reads and writes fast.
- Indexes can include keys from embedded documents and arrays.
- Optional streaming writes (no acknowledgments).
- Replicated servers with automatic master failover.
- Automatic sharding distributes collection data across machines.
- Eventually-consistent reads can be distributed over replicated servers.