Advice for backend implementation of collaborative editing?

I’m thinking about using ProseMirror for our app. It looks like it has the capabilities that we need. Because of the way our database is set up I quite like the pull and rebase approach compared to OT. I’m not super keen on storing tons of rows for each OT update.

But I’m still a little unclear about how the backend would need to be set up. And I’d like to learn a little more about the best practice before spending time learning a new library. Does anyone have any articles or suggestions that could point me in the right direction?

little unclear

The publically hosted example + source code is a start: