Apache CouchDB is a distributed, fault-tolerant and schema-free document-oriented database accessible via a RESTful HTTP / JSON API. It includes incremental map / reduce mechanics for queries and keeps data safe with an append-only datastore.

Apache CouchDB is a distributed, fault-tolerant and schema-free document-oriented database accessible via a RESTful HTTP / JSON API. It includes incremental map / reduce mechanics for queries and keeps data safe with an append-only datastore.

With an SQL-style query language, real-time queries with highly-efficient related data retrieval, advanced security permissions for multi-tenant access, and support for performant analytical workloads, SurrealDB is the next generation serverless database.

YDB is an open source Distributed SQL Database that combines high availability and scalability with strong consistency and ACID transactions.
GUN is an open source, realtime, graph database written entirely in JavaScript and built using peer-to-peer algorithms, making it surprisingly fault tolerant and easy to get started with.

TiDB is an open-source NewSQL database that supports Hybrid Transactional and Analytical Processing (HTAP) workloads. It's MySQL compatible and can provide horizontal scalability, strong consistency, and high availability.

StarRocks, a Linux Foundation project, is a next-generation sub-second MPP OLAP database for full analytics scenarios, including multi-dimensional analytics, real-time analytics, and ad-hoc queries. InfoWorld’s 2023 BOSSIE Award for best open source software.

high-performance, integrated and distributed in-memory platform for computing and transacting on large-scale data sets in real-time.