CollabCode

A collaborative coding environment where multiple people can write and run code together in real time. Built for pair programming, interviews, or just hacking with friends.

What it does

• Shared code editor that syncs as you type — no lag, no conflicts
• Run code directly in the browser (Python, JavaScript, TypeScript, Go)
• Collaborative whiteboard for diagrams and notes
• Voice and video via Agora
• Room-based: create a room, share the link, host approves who joins

Tech

• Frontend — React, CodeMirror, tldraw, Yjs
• Backend — Express, Hocuspocus
• Code execution — Piston (sandboxed, self-hosted)
• Voice/video — Agora

Running locally

npm install

# Start the server
npm run dev:server

# Start the client (in a separate terminal)
npm run dev:client

You'll also need Piston running for code execution:

docker compose -f docker-compose.piston.yml up -d

Then install the language runtimes you want using the Piston CLI. Runtimes are persisted in data/piston/packages so you only need to do this once.

Copy apps/server/.env.example to apps/server/.env and fill in your Agora credentials if you want voice/video. It's optional — everything else works without it.

Deploying

See docs/deployment.md.