Push Messages or Push Notifications are notifications from an App that display while that app is not actively in use. They are handled by a device’s operating system and typically appear on the lock screen. In essence, a push notification is a brief message or alert that is sent through an app to everyone who has opted in to the receipt of these messages.
When a user taps a Push message, it launches the app. (For progressive web apps, push messages currently work for Android devices but not for iOS devices, so iPhone users cannot receive push messages to a PWA.
Alternately, “In-app” messages appear in an App when the user views the App. They drop down from the top of the display (after a selected delay) and will stay until dismissed or selected.
When selected, an In-app message will perform an action within the app. For example, an In-app message prompting an App install might link to a microsite with directions on how to do so. Similarly, it can connect to a URL (i.e., Link Action), a Subpage, initiate a Call, etc.
In-app messages work on both iOS and Android. They appear on the page where the Action is used, which can be the App's main page or on a subpage.