Redis is an in-memory database that persists on disk. The data model is key-value, but many different kind of values are supported: Strings, Lists, Sets, Sorted Sets, Hashes, HyperLogLogs, Bitmaps.

The open-source database for the realtime web.

The Mongo Database

- PouchDB is a pocket-sized database.

Distributed Graph Database

A distributed, fault-tolerant graph database

Mirror of Apache CouchDB

Riak is a decentralized datastore from Basho Technologies.

Graphs for Everyone

OrientDB is the first Multi-Model DBMS with Document & Graph engine. OrientDB can run distributed (Multi-Master), supports SQL, ACID Transactions, Full-Text indexing, Reactive Queries and has a small memory footprint. OrientDB is licensed with Apache 2 license and the development is driven by OrientDB LTD and a worldwide Open Source community.

A distributed multi-purpose NoSQL database with a flexible data model for documents, graphs, and key-values.

MapDB provides concurrent Maps, Sets and Queues backed by disk storage or off-heap-memory. It is a fast and easy to use embedded Java database engine.

A linq enabled document database for .NET