FleetDB
FleetDB offers a flexible and expressive data model designed for the needs of modern application developers; a combination of schema-free records, declarative queries, automatically maintained indexes, and an optimizing query planner make it easy to manipulate and retrieve data. By keeping all data in RAM as persistent data structures, FleetDB is able to offer multi-record transactions, excellent concurrency semantics, and high performance. Writing to an append-only log provides durability in the form of a single file that can be transfered and analyzed using standard Unix tools. FleetDB is accessible via a simple JSON-based protocol that is implemented by clients in several programming languages.
