Hi,
I'm currently working on a pokemon type game clone. It includes the API serverside setup with nodejs and rethinkdb. The app will send json data encrypted to the server and back to the app. The map service will be mapbox or google maps. It will also work on all three major app stores Windows Universal Store, iOS Store and Google Play Store.
If you need the server set, scale, load balanced and hosted that will be extra unless you decide to host the app and service yourself.