Siaqodb is a NoSQL embedded object and document database engine that currently runs on .NET, MonoMac, Universal Windows Platform (UWP), Xamarin.iOS, Xamarin.Android, Xamarin.Mac and Unity3D. 

Siaqodb client side database may be synchronized with a Cloud/Server side database like CouchDB, MongoDB or Azure Storage. 

ObjectDB and DocumentDB – objects of an object graph may be stored individually or as a single unit called document.
Fully ASYNC API
ACID transactions – uses a powerful storage engine: LMDB
Small footprint, no extra dependencies
Built-in or plug-able Encryption Support
SiaqodbManager – managed stored data, run ad-hoc LINQ queries

Full LINQ provider
Full POCO support
Portable Class Library support
Partial object loading and Eager loading
May store full object graphs, Arrays, Lists, Dictionaries, etc.
Thread Safe – full support for ASP.NET based apps
Outstanding Performance – see comparison with RavenDB or with SQLite