what is centrifugo fr?

Centrifugo is a self-hosted server that pushes real-time messages to users the moment something happens, without them having to ask. Think of it as the plumbing behind features like live chat, live comment feeds, multiplayer game state updates, or dashboards that refresh automatically. It sits between your application backend and your users, and when your backend publishes a message, Centrifugo instantly forwards it to everyone currently connected who subscribed to that topic. The server uses a publish-subscribe model: your backend sends a message to a named channel, and all connected clients who joined that channel receive it. Connections from browsers and mobile apps can use several different transport methods, including WebSocket, Server-Sent Events, and GRPC. This flexibility means you can pick the connection type that fits your platform best without rewriting the server logic. Because Centrifugo is language-agnostic, your backend can be Python, Ruby, PHP, Node.js, or anything else, as long as it can make an HTTP or GRPC call. For teams that need to handle a large number of simultaneous connections, Centrifugo can scale horizontally using Redis or Nats as a shared message broker between multiple server instances. It also keeps a short history of recent messages in each channel so that users who reconnect briefly after dropping off can catch up on what they missed. Online presence information (knowing who is currently connected to a channel) and join or leave notifications are also built in. Authentication is handled either through JWT tokens or by asking your own backend to approve each connection. An embedded admin web interface lets you inspect channels and connections. Prometheus metrics and an official Grafana dashboard are included for monitoring. The project positions itself as a self-hosted alternative to commercial real-time messaging services, intended to run once and stay running without ongoing configuration changes.