RethinkDB

Acquired

The open source database for the realtime web.

Summer 200911 peopleSan Francisco, CA, USA

rethinkdb.com ↗Crunchbase ↗See on the Idea Map B2B momentum

About

RethinkDB is the first open-source scalable database for the realtime web. It exposes an exciting new access model -- instead of polling for changes, the developer can tell the database to continuously push updated query results to applications in realtime. RethinkDB allows developer to build scalable realtime apps in a fraction of the time with fewer engineering resources. RethinkDB features a pleasant and powerful query language that has useful queries like table joins and groupBy, a highly parallelized architecture, and web tools for managing clusters.

From their website

as of Jun 7, 2026rethinkdb.com ↗

Open source

RethinkDB is an open-source, scalable database designed to push JSON data to apps in real time, enabling building realtime web and mobile applications with less engineering effort.

RethinkDB provides a distributed database with a modern storage engine and buffer cache. It allows querying JSON documents across languages (Python, Ruby, Node.js and more), supports real-time changes via streaming (changes), and offers built-in sharding and replication controllable via a web UI or API for precise cluster management. It emphasizes realtime data pushes to clients, with native features for joins, geolocation, aggregations, and map/reduce, and integrates with frameworks and signaling tech like Socket.io or SignalR for end-to-end realtime apps.

Who it’s for: Developers and organizations building realtime web/mobile applications and services that require live data streaming, dashboards, multiplayer experiences, realtime marketplaces, analytics, or IoT data flows.

Features

Realtime data changes stream to clients
Distributed, sharded, and replicated cluster management
Querying JSON documents with multi-language support
Built-in joins, aggregations, and map/reduce
Geolocation and time-series data support
Web UI and API for cluster control and monitoring
Integration with realtime frameworks (Socket.io, SignalR)

Active development history with releases, community involvement, and developer meetup presence; mentions of large adoption and open-source community contributions.