From the webpage:
A universal open-source database with a flexible data model for documents, graphs, and key-values. Build high performance applications using a convenient sql-like query language or JavaScript/Ruby extensions.
Design considerations:
In a nutshell:
- Schema-free schemas with shapes: Inherent structures at hand are automatically recognized and subsequently optimized.
- Querying: ArangoDB is able to accomplish complex operations on the provided data (query-by-example and query-language).
- Application Server: ArangoDB is able to act as application server on Javascript-devised routines.
- Mostly memory/durability: ArangoDB is memory-based including frequent file system synchronizing.
- AppendOnly/MVCC: Updates generate new versions of a document; automatic garbage collection.
- ArangoDB is multi-threaded.
- No indices on file: Only raw data is written on hard disk.
- ArangoDB supports single nodes and small, homogenous clusters with zero administration.
I have mentioned this before but ran across it again at: An experiment with Vagrant and Neo4J by Patrick Mulder.