Building a Real-Time Collaborative Editor with CRDTs and Yjs

Building a Real-Time Collaborative Editor with CRDTs and Yjs Published target: Smashing Magazine | Estimated read: 15 minutes | Topics: JavaScript, WebSockets, Real-Time Apps Introduction: The Hard Problem of Collaboration You open a shared Google Doc with a colleague, both start typing at the same time, and somehow — magically — neither of you overwrites the other's work. Your edits appear in theirs, their edits appear in yours, and the document stays coherent even if the network flickers for a few seconds. Behind that magic is one of the most elegant unsolved problems in distributed systems: how do you merge concurrent edits from multiple users into a single consistent document, without a central authority deciding who "wins"? The naive answer — last write wins — destroys data. Operational transforms (OT), the approach Google Docs originally used, work but are fiendishly complex to implement correctly. For years, building collaborative features meant either using Google's infrastruct