What are some alternatives?
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
deployd - API development tool for Web and Mobile developers.
Backand - Backand is a backend-as-a-service for AngularJS that provides out-of-the-box social login, push notifications, Ionic integration and more.
RemoteStorage - An open protocol for per-user storage OWN YOUR DATA
GUN - Self-hosted Firebase.
PubNub - PubNub is a real-time messaging system for web and mobile apps that can handle API for all platforms and push messages to any device anywhere in the world in a fraction of a second without having to worry about proxies, firewalls or mobile drop-offs.