Yjs

Yjs is a CRDT implementation that exposes its internal data structure as shared types. Shared types are common data types like Map or Array with superpowers: changes are automatically distributed to other peers and merged without merge conflicts.

Yjs is network agnostic (p2p!), supports many existing rich text editors, offline editing, version snapshots, undo/redo and shared cursors. It scales well with an unlimited number of users and is well suited for even large documents.