# NATS

> Apache-2.0 subject-based messaging and streaming fabric

**Category:** Comms  
**Pricing:** open-source  
**URL:** https://nats.io  
**GitHub:** https://github.com/nats-io/nats-server  
**Added:** 2026-09-04

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## The Hook

NATS is the subject-based messaging fabric you run when sockets alone are the wrong layer.

## What's Good

Apache-2.0. OSS self-host at $0. Pub/sub, request/reply, queue groups, JetStream streaming. Tiny Go server, clients across languages. CNCF project.

## The Catch

Subject-based messaging/streaming fabric — not an in-process WS lib and not a Go realtime binary alone. Distinct from Socket.IO and Centrifugo.

## Verdict

Apache-2.0 messaging fabric. Free as in you run the server. Not Socket.IO.