Centrifugo

Centrifugo is an open-source, self-hosted real-time messaging server written in Go that handles persistent client connections over WebSocket, HTTP-streaming, SSE, WebTransport, and gRPC. It provides a publishing API along with pub/sub messaging and state synchronization primitives, allowing applications to add realtime updates without changing existing architecture. It can scale across multiple nodes using built-in integrations with brokers including Redis (and Redis-compatible storages), PostgreSQL, and NATS.

Features include flexible authentication, various subscription types, channel history, online presence, delta updates, and proxying of connection events to the backend. The client protocol supports JSON and binary Protobuf, and official SDK libraries are available for web and mobile development. A PRO edition adds capabilities such as ClickHouse analytics, realtime tracing, performance optimizations, a push notification API, and SSO integrations for the web UI. Centrifugo is developed by Centrifugal Labs LTD and is packaged as an open-source version with a separate PRO offering for corporate and enterprise environments.