MySQL and PostgreSQL-compatible relational database built for the cloud. Performance and availability of commercial-grade databases at 1/10th the cost.

experts

Redis is an open source in-memory data structure project implementing a distributed, in-memory key-value database with optional durability.

experts Open Source

PostgreSQL is a powerful, open source object-relational database system.

experts Open Source

MongoDB (from "humongous") is a scalable, high-performance NoSQL database.

nominated Open Source