##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
Real-time collaboration
Functional: Create documents, edit text, multiple simultaneous editors, comments, version history.
Non-functional: + concurrent editors per document. Changes visible within ms. No data loss on conflicts. Offline editing support.
Core challenge: Two users edit the same sentence simultaneously. Whose change wins? How do you merge without losing either edit?
