There is a web app. Required from the server of this application to deliver push to mobile devices, with FCM if everything is OK, but iOS made the bases. Saw your app with APNs to signup Apple developer ACC, only to deliver pushey, have neither the time nor the desire.
Therefore, the question arose about the third-party service. PushBullet't taken off on iOS. A pushover for $ 5 per user per month - beyond good. Will be about 300 users 1.5 K$ a month for a minor service is awesome. A single would have a ride as well... is There even something similar?
Actually since the question is solved with FCM that is interested in the service for iOS.