Co-Edit: Real-Time Collaborative Editor

Overview

Co-Edit is a collaborative editor built during the HCL Hackathon (GUVI) to deliver fast, conflict-free multi-user editing using Yjs CRDTs. The app focuses on low-latency sync, offline-first reliability, and a smooth writing experience with rich text formatting and AI-assisted commands.

It combines a Next.js frontend, a Node.js + Express backend, WebSocket-based synchronization, and Neon PostgreSQL for persistence.

Why I Built This

• Traditional collaborative editors can feel delayed when many users edit at once.
• I wanted to integrate auto complete and professional rewrite of the document in the editor itself instead of playing between Editor and ChatGPT
• I also wanted to explore CRDT architecture deeply and build a practical, production-style project around it.

Key Features

• CRDT-Powered Real-Time Sync: Conflict-free collaboration with Yjs over WebSocket.
• Offline-First Editing: Local persistence with IndexedDB and seamless reconnect sync.
• Presence and Awareness: Live cursors, active-user indicators, and collaborator state.
• AI Writing Commands: Refine, summarize, and continue-writing commands powered by Groq.
• Rich Text Experience: Tiptap editor with professional formatting tools.
• Versioning and Recovery: Timeline-based history and restore flow.
• Export and Sharing: Document export and share-ready collaboration links.

System Architecture

Lessons Learned

1. CRDTs require an eventual-consistency mindset rather than server-ordered operations.
2. Binary Yjs updates dramatically reduce payload size for high-frequency edits.
3. Presence synchronization is as important as document synchronization for collaboration UX.
4. Offline-first persistence improves both reliability and perceived performance.
5. Low-latency LLM APIs are practical for interactive editor workflows.