Collaborate. is a production-focused anonymous real-time whiteboard built to demonstrate that the project owner can design, ship, and operate a small collaborative system with engineering discipline.

• Share a room link with no auth flow
• Draw with mouse, touch, or stylus
• Use pen, eraser, color, and stroke width controls
• Undo and redo your own strokes
• Clear only your own content
• Export the current board to PNG
• Rejoin the same room after refresh or transient disconnect
• Expire empty rooms automatically after a bounded TTL

• apps/web - React + Vite frontend
• apps/api - Express + Socket.IO backend
• packages/contracts - shared event names, schemas, and types
• docs - product, roadmap, and deployment notes
• v1 - archived demo reference

• RoomPage owns room entry and board presentation
• useRoomSession owns socket lifecycle, sync, and reconnect behavior
• useBoardCanvas owns pointer input, local drawing, and export
• AppErrorBoundary contains runtime crashes behind a controlled fallback

• RoomService owns room lifecycle and board mutation rules
• RoomRepository abstracts storage
• registerSocketHandlers validates and gates every socket event
• createHttpApp exposes health, readiness, and metrics

All socket event names and payload schemas are defined once in packages/contracts and imported by both apps.

1. First valid join creates a room.
2. The API keeps canonical board state for the room.
3. Refreshing the same room auto-rejoins with the last successful local identity.
4. When the last participant leaves, the room enters expiring state.
5. Empty rooms are deleted after ROOM_EMPTY_TTL_MS.

The default repository mode is file-backed ephemeral storage.

• ROOM_REPOSITORY=file persists room state to ROOM_STORAGE_PATH
• ROOM_REPOSITORY=memory is intended for tests and disposable local runs

This gives the project restart-safe rooms on a single API instance without reintroducing the original in-process-only limitation.

npm install

cp apps/api/.env.example apps/api/.env
cp apps/web/.env.example apps/web/.env

npm run dev:api

npm run dev:web

Default URLs:

• Web: http://localhost:5173
• API: http://localhost:5000
• Health: http://localhost:5000/health
• Readiness: http://localhost:5000/ready
• Metrics: http://localhost:5000/metrics

npm run lint
npm run typecheck
npm run test
npm run build
npm run e2e

If Playwright browsers are not installed locally:

npx playwright install chromium

If you want to reuse a system Chrome instead:

PLAYWRIGHT_EXECUTABLE_PATH=/usr/bin/google-chrome npm run e2e

• Zod validation on every socket payload
• Payload size limits
• Per-socket rate limiting
• Structured JSON logs
• Prometheus-style metrics
• Frontend error boundary
• Unhandled rejection and exception shutdown logging
• Bounded room history and bounded stroke sizes

• PRD: docs/PRD.md
• Implementation roadmap: docs/IMPLEMENTATION_ROADMAP.md
• Deployment notes: docs/DEPLOYMENT.md