CouchDB

Apache CouchDB, commonly referred to as CouchDB, is an open source database that focuses on ease of use and on being "a database that completely embraces the web". It is a NoSQL database that uses JSON to store data, JavaScript? as its query language using MapReduce?, and HTTP for an API. One of its distinguishing features is multi-master replication. CouchDB was first released in 2005 and later became an Apache project in 2008.

Installing

It's easy