Real-Time Collab Editor

Real-Time Collab Editor — Backend Engineering

I built a highly concurrent, real-time document synchronization server using Yjs CRDT (Conflict-free Replicated Data Type), WebSockets, and SQLite for persistence. The backend features debounce saving mechanisms and real-time awareness updates to show active users and their cursors seamlessly.

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Technologies

• Node.js & Express.js
• WebSockets (ws)
• Yjs & y-protocols (CRDT)
• SQLite3

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Key Implementations

• Engineered a custom WebSocket server to handle real-time binary data transmission for document state and user awareness.
• Implemented Yjs CRDT algorithms to ensure conflict-free document synchronization across multiple concurrent clients.
• Developed an efficient debounce-save mechanism to persist document state to an SQLite database without overwhelming disk I/O.
• Managed WebSocket lifecycle, client IDs, and awareness states to broadcast accurate real-time user presence.

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