How Notion handles concurrent editing with CRDTs

They didn't link the presentation that was done on this work by Angelique Nehmzow at Local-First Conf (9 months prior): https://www.youtube.com/watch?v=AKDcWRkbjYs

The way they’ve handled splits in text using a “text slice” and block mapping is truly novel (although the way they’ve introduced search labels feels a little hacky).

> in a ProseMirror editor using Yjs, splits are modeled as a deletion in the first block and an insertion in the second. A concurrent edit may therefore remain in the original node, whereas our approach preserves its intended position across the split.

I wonder if something inspired by this design could make its way into the new Yjs version and y-prosemirror rewrite.

It’s always been a big limitation of y-prosemirror that splits are handled as a deletion and insertion.

Posted in the future?

> Published September 19, 2026 in Tech