I would almost certainly build the back end from the ground up based on the concept of a stream of events. Current state is then expressed as left fold over a base empty state and all of the event types you're interested in.

Benefits that I can see:

* Purity. You can test the hell out of this with no side effects.

* Transaction log built in.

* The ability to look back in time, by only applying the events up until the point you're interested in and disregarding the rest.

* Very flexible and scalable.

* You can retrospectively answer questions that you might not have known how to ask, by creating new operations over your states.

* Plays well with monitoring, and analysis. E.g. just stream all of your events into logstash and elastic search.