{"data":{"slug":"nats","name":"NATS","tagline":"Apache-2.0 subject-based messaging and streaming fabric","category":"comms","categoryName":"Comms","url":"https://nats.io","github":"https://github.com/nats-io/nats-server","pricing":"open-source","hook":"NATS is the subject-based messaging fabric you run when sockets alone are the wrong layer.","whatsGood":"Apache-2.0. OSS self-host at $0. Pub/sub, request/reply, queue groups, JetStream streaming. Tiny Go server, clients across languages. CNCF project.","theCatch":"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.","addedAt":"2026-09-04","featured":false,"domain":"Comms","subSpecialty":"Realtime","capabilities":["messaging","streaming"],"surfaces":["Self-host"],"ecosystem":["Go","Multi-platform"],"licenseModel":"Apache-2.0","githubStars":20657},"related":[{"slug":"livekit","name":"LiveKit","tagline":"Apache-2.0 realtime rooms, SFU, and agents"},{"slug":"chatwoot","name":"Chatwoot","tagline":"MIT-core support inbox you can self-host for $0/agent"},{"slug":"socket-io","name":"Socket.IO","tagline":"MIT realtime library with fallbacks, not a hosted product"},{"slug":"plunk","name":"Plunk","tagline":"AGPL-3.0 transactional email, workflows, and broadcasts"},{"slug":"centrifugo","name":"Centrifugo","tagline":"Apache-2.0 Go realtime server binary, not in-process Socket.IO"}],"links":{"self":"/api/gems/nats","html":"/gems/nats","markdown":"/gems/nats.md","category":"/api/gems?category=comms","categoryPage":"/stacks/comms"}}