RoomCall

A real-time, peer-to-peer video calling application built with Next.js and WebRTC. Create or join rooms instantly — no account required.

Features

• Instant rooms — Generate a unique room code and share it with anyone
• HD video & audio — Peer-to-peer media via WebRTC for low-latency calls
• Mute / camera toggle — Control your mic and video independently at any time
• Screen sharing — Share your screen with all participants in the room
• Live in-call chat — Real-time text chat via RTCDataChannel (no server relay)
• Multi-participant — Mesh topology supports multiple users in one room
• No sign-up — Enter a display name and join, that's it

Tech Stack

Layer	Technology
Framework	Next.js 16 (App Router)
UI	React 19, Tailwind CSS v4, Lucide icons
Real-time	WebRTC (RTCPeerConnection, RTCDataChannel)
Signaling	Socket.io v4 (custom Node.js server)
Language	TypeScript
Fonts	Geist Sans / Geist Mono

Architecture

Browser A                    Signaling Server (server.js)           Browser B
   |                                    |                               |
   |── join-room ─────────────────────>|                               |
   |<─ room-users (empty) ─────────────|                               |
   |                                   |<──────────── join-room ───────|
   |<─ user-joined ─────────────────── |─── room-users ([A]) ─────────>|
   |                                   |                               |
   |── offer ──────────────────────────────────────────────────────── >|
   |<─ answer ──────────────────────────────────────────────────────── |
   |<──────────────────── ICE candidates (both ways) ─────────────────>|
   |                                                                   |
   |<═══════════════════ P2P media + data channel ═══════════════════>|
                         (no server involved)

Key Design Decisions

• Mesh topology — Every peer connects directly to every other peer. Best for small groups (2–8 people). No SFU/MCU needed.
• Signaling via Socket.io — Used only to exchange SDP offers/answers and ICE candidates. Once the call is established, the signaling server is no longer in the media path.
• In-call chat via RTCDataChannel — Chat messages travel peer-to-peer. The server never sees message content.
• Screen sharing via replaceTrack — Swaps the video track on all existing peer connections without renegotiation.
• Custom Next.js server — server.js wraps Next.js with http.createServer, allowing Socket.io to share the same port.

Folder Structure

web-rtc/
├── server.js                          # Custom Node.js server (Next.js + Socket.io)
├── signaling-server/                  # Standalone signaling server (for split deployments)
│   ├── server.js
│   └── package.json
├── src/
│   ├── app/
│   │   ├── layout.tsx                 # Root layout (fonts, metadata)
│   │   ├── page.tsx                   # Home page (Create Room / Join Room)
│   │   ├── globals.css                # Global styles + Tailwind v4
│   │   └── room/
│   │       └── [roomId]/
│   │           ├── page.tsx           # Room route (async params)
│   │           └── _components/
│   │               ├── RoomClient.tsx # Main room orchestrator
│   │               ├── PreJoin.tsx    # Name entry screen before joining
│   │               ├── VideoTile.tsx  # Individual video/avatar tile
│   │               ├── Controls.tsx   # Bottom control bar
│   │               └── ChatPanel.tsx  # Slide-in chat panel
│   ├── hooks/
│   │   └── useWebRTC.ts               # Core WebRTC hook (connections, signaling, media)
│   ├── lib/
│   │   └── webrtc.ts                  # RTCConfiguration (STUN servers)
│   └── types/
│       └── index.ts                   # Shared TypeScript types
├── .env.local                         # Local environment variables (gitignored)
├── .env.example                       # Environment variable template
└── next.config.ts                     # Next.js config

Getting Started

1. Install dependencies

npm install

2. Configure environment

cp .env.example .env.local
# .env.local defaults work for local development — no changes needed

3. Run the development server

npm run dev

Open http://localhost:3000.

Note: npm run dev runs node server.js, not next dev. This is required because Socket.io needs a persistent Node.js HTTP server.

Environment Variables

Variable	Default	Description
PORT	3000	Port for the Node.js server
NEXT_PUBLIC_SOCKET_URL	(same origin)	URL of the signaling server. Leave empty in dev. Set to your deployed signaling server URL in production.
FRONTEND_URL	http://localhost:3000	(Signaling server only) Allowed CORS origin

Deployment

Option A — Railway (recommended, everything in one)

Railway supports persistent Node.js processes. No changes needed to the code.

1. Push your repo to GitHub
2. Go to railway.app → New Project → Deploy from GitHub
3. Set environment variable: NODE_ENV=production
4. Railway auto-detects npm run build and npm run start

Option B — Vercel (frontend) + Railway (signaling)

Vercel is serverless and cannot run Socket.io. Split the deployment:

1. Deploy signaling-server/ to Railway as a separate service
   • Set FRONTEND_URL=https://your-app.vercel.app in Railway env vars
2. Deploy the Next.js frontend to Vercel
   • Set NEXT_PUBLIC_SOCKET_URL=https://your-signal.railway.app in Vercel env vars
   • Build command: npm run build

Why not Vercel for everything? Vercel's serverless functions are stateless and terminate between requests. Socket.io requires a persistent process to maintain WebSocket connections and room state.