activitree:push is based on Firebase for all IOS, Android and Web. For web, it requires a web worker all documented in the repo. Just a heads up if you go there, the github content is not a Meteor project, it only shows where different files and folders should exist. You can look at it as a folder structure rather than a meteor project that you can run in your development machine.
We support notifications on mobile, in browsers and via email – including some specialized variations of these. We’re vanilla Cordova, thus:
Client-side, on mobile, we use the cordova-plugin-push. For browsers, we use the JavaScript Notification API. And email of course just calls Meteor mail.
Server-side, we are using NPM’s apn and node-gcm. These are older, but certainly tried and true
Keep in mind, while Google simply authenticates with an ID, Apple uses certs. You’ll need to attach those, presumably decrypting the source versions, as part of your build.