Best realtime and WebSocket tools (2026)

1. 1.LiveKitApache-2.0 realtime rooms, SFU, and agents

   Free / OSS · Apache-2.0 · 21.6k GitHub stars

   VerdictApache-2.0 voice/video/agent runtime. Self-host is the free path; Cloud pricing is not confirmed here.

   CatchSelf-hosting an SFU is ops-heavy. Cloud Build pricing and free allowances are not confirmed here; check the vendor site. Do not assume Cloud is free.

2. 2.Socket.IOMIT realtime library with fallbacks, not a hosted product

   Free / OSS · OSS/MIT · 63.2k GitHub stars

   VerdictThe MIT socket library. Free as in you run it.

   CatchYou bring the host. Horizontal scale needs Redis (or equivalent) adapter. This is not LiveKit and not a managed pub-sub. CORS, sticky sessions, and polling surprises remain your bugs.

3. 3.CentrifugoApache-2.0 Go realtime server binary, not in-process Socket.IO

   Free / OSS · Apache-2.0 · 10.9k GitHub stars

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

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

4. 4.YjsMIT CRDT library, not a hosted collab product

   Free / OSS · OSS/MIT · 22.9k GitHub stars

   VerdictThe MIT CRDT. Pair with Liveblocks for hosted rooms; this is the library, not the meter.

   CatchNot a product. No hosted SKU, no pricing page, no support SLA. You bring the network layer (Liveblocks, y-websocket, your own). Distinct from Socket.IO: CRDT merge, not event fan-out.

5. 5.MercureAGPL-3.0 SSE hub; homepage still says MIT

   Free / OSS · AGPL-3.0 · 5.3k GitHub stars

   VerdictAGPL SSE hub. Believe the LICENSE file, not the MIT line on the homepage.

   CatchHomepage still says the Hub is MIT-licensed. The LICENSE file is AGPL-3.0 — print the file. SSE, not WebSockets, not Pusher protocol. Distinct from Socket.IO and Soketi. Cloud/Enterprise exist; check their pricing page. OSS self-host is the free path.

6. 6.NATSApache-2.0 subject-based messaging and streaming fabric

   Free / OSS · Apache-2.0 · 20.9k GitHub stars

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

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

7. 7.AnyCableMIT realtime for Action Cable with delivery guarantees

   Free / OSS · Freemium · 2.4k GitHub stars

   VerdictMIT Action Cable path. OSS tier is free; not Soketi, not Socket.IO.

   CatchDelivery guarantees + presence + Action Cable / multi-backend — not a Pusher-protocol server. Distinct from Socket.IO and Centrifugo. Pro and Managed exist; prices not reprinted here.

8. 8.mediasoupISC embeddable SFU as a Node module or Rust crate

   Free / OSS · ISC · 7.4k GitHub stars

   VerdictISC embeddable media router. Free as in you wire it. Not LiveKit.

   CatchEmbeddable media router as Node module/Rust crate — not LiveKit rooms/agents product. Distinct from LiveKit.

9. 9.Pion WebRTCMIT embeddable Go WebRTC library — not a rooms product

   Free / OSS · OSS/MIT · 16.9k GitHub stars

   VerdictMIT Go WebRTC library. Free to embed; not a rooms stack.

   CatchEmbeddable Go library — not LiveKit rooms product, not mediasoup C++/Node media server, not PeerJS browser-only P2P helper. You assemble signaling and any SFU-class topology yourself. Distinct from LiveKit, mediasoup, and PeerJS.

10. 10.Janus GatewayGPL-3.0 plugin-core WebRTC gateway (SIP, VideoRoom, streaming)

    Free / OSS · GPL-3.0 · 9.2k GitHub stars

    VerdictGPL-3.0 WebRTC gateway. Self-host free; commercial options exist — pitch the OSS core.

    CatchPlugin-core C gateway — not LiveKit/mediasoup opinionated rooms products. You pick plugins and ops the gateway. Distinct from LiveKit, mediasoup, PeerJS, and Pion.

Also reviewed (14)

• SocketCluster — MIT Node pub/sub+RPC+JWT with SCC scale-out
• Laravel Reverb — MIT first-party Laravel WebSocket server
• Tuwunel — Apache-2.0 Matrix homeserver; official conduwuit successor
• matrix-js-sdk — Apache-2.0 Matrix client library — needs a homeserver
• Eclipse Mosquitto — EPL-2.0 / BSD-3 MQTT broker; OSS self-host forever free
• Sockudo — MIT Rust Pusher V1 edge + Protocol V2 recovery/history/push
• PartyKit — MIT realtime rooms on Cloudflare Durable Objects; pay CF Workers only
• Jitsi Meet — Apache-2.0 self-host Meet + free meet.jit.si; JaaS optional
• gatho — MIT self-host WebSocket rooms toolkit; no Cloud product
• Trystero — MIT serverless WebRTC rooms via Nostr/MQTT/BitTorrent/IPFS
• MQTT.js — MIT Node + browser MQTT client — needs a broker
• coturn — BSD-3-Clause TURN/STUN NAT-traversal relay (not an SFU)
• PeerJS — MIT browser P2P WebRTC with free cloud or self-host signaling
• Liveblocks — Hosted collab rooms; Free $0 pauses at the cap