3rd YearAdvancedWeb 12-16 weeks
Real-Time Collaborative Code Editor
A VS Code-like collaborative editor where multiple users edit the same file simultaneously — changes are synchronized in real time using Operational Transformation or CRDTs.
ReactNode.jsYjs (CRDT)WebSocketsMonaco EditorDocker
Find GitHub repos & source code →How to build it — step by step
- 1CRDT Integration: Use Yjs Y.Text CRDT for conflict-free concurrent edits; bind to Monaco Editor with y-monaco
- 2Presence System: Show other users' cursors and selections in real time with user color coding and name labels
- 3Execution Engine: Submit code to Piston API for execution; show output panel below editor
- 4Session Management: Shareable room URLs; room state persisted in Redis; reconnection with diff sync on rejoin
Key features to implement
- ✓Real-time multi-user concurrent editing
- ✓Other users' cursors visible with names
- ✓In-browser code execution (10+ languages)
- ✓Voice/video chat integration (WebRTC)
- ✓Session recording and replay
💡 Unique twist to stand out
Add "AI Pair Programmer" mode where a chat sidebar powered by GPT-4o observes the current code in real time and proactively suggests improvements or catches bugs as you type.
🎓 What you'll learn
CRDTs for distributed state, WebRTC, collaborative algorithms, and building production-grade collaborative applications.