since the discussion on this thread is quite old and with the new MongoDB Realm (after MongoDB acquired Realm), the services that a mobile developer has access to now are very very enabling, we really hope realm support hits the roadmap as soon as possible,
So I am posting this as a heads-up and to get the core team views on it,
Our general philosophy going forward is that we want to minimize, or ideally even eliminate reliance on third party online services (that might disappear or not be available in certain countries or might be overtaken by competitors or just work less well for you than a competitor) in the core SDK. We want the the core SDK to become a universal standard.
That said, we know there are tons of libraries like Realm and others that people really want to use, and so we’re looking at different ways to make it possible to use as many of them as possible – without having to wait for the Expo team to add support to the core. We’re working on something promising now but its not ready yet. Stay tuned.
@ccheever thanks for the clarifications, appreciate all the wonderful work Expo team is doing,