The App API handles high level App state and events.For example, this API emits events when the app enters and leaves the foreground, handles deeplinks, opens other apps, and manages persisted plugin state.
Share text, images (and other files), or a link via the native sharing widget of your device. Android is fully supported, as well as iOS 6 and up. WP8 has somewhat limited support.
OneSignal is a high volume Push Notification service for mobile apps. In addition to basic notification delivery, OneSignal also provides tools to localize, target, schedule, and automate notifications that you send.