# Centrifugo

> Apache-2.0 Go realtime server binary, not in-process Socket.IO

**Category:** Comms  
**Pricing:** open-source  
**URL:** https://centrifugal.dev  
**GitHub:** https://github.com/centrifugal/centrifugo  
**Added:** 2026-09-03

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## The Hook

Centrifugo is the Go realtime server you run next to your app, not a library inside it.

## What's Good

Apache-2.0. Language-agnostic PUB/SUB: WebSocket, HTTP-streaming, SSE, gRPC, WebTransport. Official SDKs. docker run centrifugo. Decouples transport from business logic.

## The Catch

You run it. This is not Socket.IO in-process. Cloud/PRO SKUs were unverified here — no invented Cloud prices. Ops, clustering, and Redis when you scale stay yours.

## Verdict

Apache-2.0 realtime binary. Free as in you operate the server.