ScreenLink

Cross-device screen sharing via WebRTC + Socket.io. One computer hosts, another views — live video stream peer-to-peer, no plugins needed.

How it works

1. Host opens the app → clicks Share Screen → gets a 6-digit code (refreshes every 5 min)
2. Viewer opens the same URL on any other device → switches to Viewer → enters the code
3. WebRTC establishes a direct peer-to-peer video stream
4. Viewer can send URLs for the host to open in new tabs

Deploy to Render (free tier)

Option A — render.yaml (recommended)

1. Push this repo to GitHub
2. Go to render.com → New → Blueprint
3. Connect your repo — Render reads render.yaml automatically
4. Deploy. Done.

Option B — Manual

1. Go to render.com → New → Web Service
2. Connect your GitHub repo
3. Settings:
   • Runtime: Node
   • Build Command: npm install
   • Start Command: npm start
   • Plan: Free
4. Deploy

After deploy

Your app will be live at https://screenlink-xxxx.onrender.com (or your custom domain). Both computers visit that URL. Host shares screen, viewer enters code.

Run locally

npm install
npm start
# Open http://localhost:3000

Tech stack

• Server: Node.js + Express + Socket.io (signaling only)
• Video: WebRTC getDisplayMedia → peer-to-peer stream
• No database — sessions are in-memory, reset on redeploy
• STUN: Google public STUN servers (free, no config needed)

Notes

• Screen sharing requires HTTPS in production — Render provides this automatically
• For localhost testing, Chrome allows getDisplayMedia on http://localhost
• The free Render tier sleeps after 15 min of inactivity (first load may be slow)
• For always-on use, upgrade to Render's paid tier or add a cron ping