Yjs

Yjs is a high-performance CRDT framework for building collaborative applications, exposing Shared Types that behave like normal data structures while automatically synchronizing across users in real time. Created by Kevin Jahns and published under the MIT License, the core library accumulates over 900,000 weekly npm downloads and powers collaborative editing at Proton for Proton Docs, Nextcloud for collaborative text editing, Evernote for shared notes, ClickUp for document collaboration, Shopify for team wikis, Monday.com for shared task boards, JupyterLab for real-time notebook editing, Atlassian for collaborative content, and Meta for Lexical-based editor collaboration. The CRDT engine enables peer-to-peer synchronization without a central coordination server, providing offline-first support where data persists in local IndexedDB and syncs when connectivity returns. Network-agnostic architecture supports WebRTC, WebSocket, and custom transport providers. The Yjs ecosystem provides ready-made integrations with ProseMirror, Quill, Monaco Editor, CodeMirror, TipTap, Lexical, and React, and language ports exist as Y-Automerge in Rust (Yrs), Swift (Yswift), WebAssembly (Ywasm), Go (Ygo), Java (Y-kv), and Kotlin. Sponsors include Tiptap, GitBook, Ellie AI, Cargo, Granola, and the GitHub Secure Open Source Fund. The project maintains active Discord, forum, and learn platforms with community-driven documentation.