How Notion rebuilt its editor around CRDTs to end concurrent-edit data loss

blaizedsouza · x · 2026-09-19

Notion engineers detail their 2025 collaborative editing overhaul. Previously the editor used last-write-wins per block: concurrent edits to the same block silently overwrote each other, and the planned Offline Mode would have made data loss far worse.

The team rebuilt the underlying system and data model with a CRDT-based conflict-free rich-text editing system, plus techniques to handle Notion's unique block-based document model, so hundreds or thousands of collaborators can edit concurrently with proper merging.

Related event: Notion Rebuilds Editor with CRDT for Real-Time Collaboration(2 posts)→

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