Pouchdb is a #Javascript implementation of #CouchDB that's particularly suited for mobile devices as you can replicate/sync between a local database on the phone to and from remote databases. You can build highly reliable systems using it that don't depend on a particular vendor or geographic location. This is something that I really value if you are building fault tolerant systems. For mobile devices Pouchdb means a fully functional offline mode that syncs with low bandwidth, and also provides optimised real-time data updates when online.