The FAQ says you can do optimistic mutations on the app state by providing an :action and a :remote true. https://github.com/omcljs/om/wiki/Om-Next-FAQ#how-can-i-implement-optimistic-commits

If you do that, does Om roll back your optimistic changes when the final result comes back from the server?

or just assume that everything will converge on the right state?

(Relay rolls it back, as I understand it.)