Centrifugo

Centrifugo is an open‑source, self‑hosted server that provides real‑time messaging through a PUB/SUB model. It accepts connections over modern transports such as WebSocket, HTTP‑streaming, Server‑Sent Events, GRPC, and WebTransport, and lets clients subscribe to channels to receive publications instantly. The server is language‑agnostic, exposing a simple HTTP/GRPC API for any backend and offering official SDKs for web and mobile development, while also supporting a lightweight unidirectional mode that requires no SDK.

The platform is built for scalability and integration with existing architectures. It can distribute load across multiple nodes using Redis (including Redis Cluster and compatible stores) or NATS, and includes features like channel history, presence notifications, delta compression, and flexible authentication via JWT or proxy callbacks. Additional capabilities include server‑side subscription multiplexing, channel permission strategies, and RPC calls over the real‑time connection.

Centrifugo is written in Go and optimized for high‑throughput scenarios, handling millions of concurrent connections on modest hardware. It is released under the MIT license, has a stable maturity level, and is used in production by various companies for chat, live dashboards, multiplayer games, collaborative tools, and other interactive applications.