Raven is an Open Source (with a commercial option) document database for the .NET/Windows platform. Raven offers a flexible data model design to fit the needs of real world systems. Raven stores schema-less JSON documents, allow you to define indexes using Linq queries and focus on low latency and high performance.
- Scalable infrastructure: Raven builds on top of existing, proven and scalable infrastructure - Simple Windows configuration: Raven is simple to setup and run on windows as either a service or IIS7 website - Transactional: Raven support System.Transaction with ACID transactions. If you put data in it, that data is going to stay there - Map/Reduce: Easily define map/reduce indexes with Linq queries - .NET Client API: Raven comes with a fully functional .NET client API which implements Unit of Work and much more - RESTful: Raven is built around a RESTful API
Raven is released under a dual Open Source license and a commercial license. Simply put, that means that it is freely available under the AGPL license but if you want to use this with proprietary software, you must buy a commercial license.