[tablatom]

This points towards a big challenge that I think gets overlooked way too often. A lot of these sync libraries/frameworks claim to solve for both real-time interaction, and local-first, sync when you reconnect. But the UX needs are wildly different.

For the former you want (as mentioned) good presence info and undo. For the latter you (sometimes) want explicitly flagged conflicts and manual resolution, like we have in git etc.

With the Replicache/Reflect model, you could actually handle both approaches. Might not be easy but the model can support it.

[archagon]

If a client is offline for a while and makes a bunch of edits, would rebasing many thousands of mutations not be a major performance issue? (For example: if complexity is O(n) per edit, as is often the case with string insertions, the process might hang for a long time.)