Centrifugo is an open-source scalable real-time messaging server. Centrifugo can instantly deliver messages to application online users connected over supported transports (WebSocket, HTTP-streaming, Server-Sent Events (aka EventSource), GRPC, WebTransport). Centrifugo has the concept of channel subscriptions – so it's a user-facing PUB/SUB server.

Centrifugo is language-agnostic and can be used to build chat apps, live comments, multiplayer games, real-time data visualizations, collaborative tools, etc. in combination with any backend. It is well suited for modern architectures and allows decoupling the business logic from the real-time transport layer.

Several official client SDKs for browser and mobile development wrap the bidirectional protocol. In addition, Centrifugo supports a unidirectional approach for simple use cases with no SDK dependency.

Documentation

• Centrifugo official documentation site
• Installation instructions
• Getting started tutorial
• Design overview and idiomatic usage
• Build a WebSocket chat/messenger app with Centrifugo tutorial
• Centrifugal blog
• FAQ

Join community

• Telegram
• Discord
• Twitter

Why Centrifugo

The core idea of Centrifugo is simple – it's a PUB/SUB server on top of modern real-time transports:

The hard part is to make this concept production-ready, efficient, flexible and available from different application environments. Centrifugo is a mature solution that already helped many projects with adding real-time features and scale towards many concurrent connections. Centrifugo provides a set of features not available in other open-source solutions in the area:

• Efficient real-time transports: WebSocket, HTTP-streaming, Server-Sent Events, GRPC, WebTransport
• Built-in scalability with Redis (or Redis Cluster, or Redis-compatible storage – ex. AWS Elasticache, Valkey, KeyDB, DragonflyDB, etc), or Nats.
• Simple HTTP and GRPC server API to communicate with Centrifugo from the app backend
• Asynchronous PostgreSQL and Kafka consumers to support transactional outbox and CDC patterns
• Flexible connection authentication mechanisms: JWT and proxy-like (via request from Centrifugo to the backend)
• Channel subscription multiplexing over a single connection
• Different types of subscriptions: client-side and server-side
• Various channel permission strategies, channel namespace concept
• Hot message history in channels, with automatic message recovery upon reconnect, cache recovery mode (deliver latest publication immediately upon subscription)
• Delta compression in channels based on Fossil algorithm
• Online channel presence information, with join/leave notifications
• A way to send RPC calls to the backend over the real-time connection
• Strict and effective client protocol wrapped by several official SDKs
• JSON and binary Protobuf message transfer, with optimized serialization and built-in batching
• Beautiful embedded admin web UI
• Great observability with lots of Prometheus metrics exposed and official Grafana dashboard
• And much more, visit Centrifugo documentation site

Backing

This repository is hosted by packagecloud.io.

Also thanks to JetBrains for supporting OSS (most of the code here written in Goland):