Quick answer
A push notification is a message sent from a server to a mobile app, displayed even when the app is closed. iOS uses APNs, Android uses FCM.
What it is
A push notification is delivered through Apple's APNs or Google's FCM. Apps register for push on first launch and receive a token. Servers send notifications to that token, which the platform delivers to the device.
Why it matters
Push is the highest-engagement channel for mobile apps. Done right, it lifts retention. Done wrong, it drives uninstalls.
How to use it
- Segment users and personalise notifications.
- Time notifications to user behaviour, not just schedule.
- Allow users to fine-tune notification preferences.
- Track opt-in rate, open rate and conversion.
Examples
- A news app sends breaking-news notifications to opted-in users.
- A fitness app sends a reminder when the user has not worked out this week.