Serverless peer-to-peer chat that runs on static hosting (GitHub Pages). No server, no database, no accounts — just WebRTC and a public MQTT broker used only for signaling.

Live: https://bartoszosiej.github.io/n2-mesh/

  ┌─────────────┐   WebRTC data channel   ┌─────────────┐
  │  Peer A     │◄───────────────────────►│  Peer B     │
  │ (your tab)  │    (direct, P2P)        │ (their tab) │
  └──────┬──────┘                         └──────┬──────┘
         │    SDP offer/answer/ICE via          │
         │    public MQTT topic (signaling only) │
         ▼                                       ▼
   ┌─────────────────────────────────────────────────┐
   │   Public MQTT broker (per-room topic)           │
   │   presence + signaling + fallback for messages  │
   └─────────────────────────────────────────────────┘

1. Peers announce their presence on a per-room MQTT topic (no account, public broker — the same way messengers discover each other).
2. When two peers see each other, they exchange WebRTC offer/answer/ICE candidates through that topic (the classic signaling-server pattern used by PeerJS & co.). The broker only introduces peers — it never sees message payloads.
3. Once connected, chat messages travel over the WebRTC data channel directly between browsers — real peer-to-peer.
4. On networks that block WebRTC (mobile carrier CGNAT), messages still flow through the MQTT topic as an automatic fallback. Recipients deduplicate by message id, so P2P stays primary and nothing is lost.

The original build found peers through public WebTorrent WebSocket trackers (tracker.webtorrent.dev, tracker.openwebtorrent.com). Those trackers now accept announces and see the swarm, but no longer relay WebRTC offers between peers — verified live: two peers registered in the same swarm (complete=2) and zero offers ever came back. Since the browser build of WebTorrent can only use WebSocket trackers (no UDP/DHT in the browser), peers could never find each other and P2P was dead. Signaling over the MQTT relay keeps the app fully serverless, works today, and matches how real messengers do it.

• 🔗 Rooms — same room name = same signaling topic = same peer group
• 💬 True P2P messages — over WebRTC data channels, with MQTT fallback
• 🏷️ Nicknames, peer counter, connection status
• 🔗 Shareable room links (#/room-name)
• 🌙 Dark UI, keyboard accessible, zero dependencies (no CDN, no build step)

python3 -m http.server 8080
# open http://localhost:8080 (and a second tab to chat with yourself)

Push to main — GitHub Actions (deploy.yml) publishes the static files to GitHub Pages automatically.

• Messages travel peer-to-peer over WebRTC data channels whenever possible; the MQTT broker performs signaling and is used as a fallback transport on restrictive networks.
• This is a demo-grade mesh: peers must be online simultaneously. There is no history — when you leave, the room is gone.