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How does the push notification service work?

Created on 2025-06-04 10:08:27
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Push notification services allow applications to send messages or alerts to users' devices even when the app is not actively running. These messages are delivered through a combination of client-side and server-side components, often leveraging operating system-specific services like Apple Push Notification Service (APNs) for iOS and Firebase Cloud Messaging (FCM) for Android.

How It Works:

  1. Registration: When a user installs an app, the app registers with the operating system's push notification service (e.g., APNs or FCM) to obtain a unique device token. This token identifies the device for future notifications.
  2. Token Delivery: The app sends this token to the app's backend server, which stores it for future use.
  3. Message Sending: When the app's backend needs to send a notification, it uses the stored device token(s) to target specific devices or groups of devices. The backend sends the message to the operating system's push notification service (e.g., APNs or FCM).
  4. Delivery: The operating system's service receives the message and delivers it to the user's device, even if the app is not open. The device then displays the notification to the user.

Example:

A messaging app like WhatsApp uses push notifications to alert users when they receive a new message. When a friend sends a message to a user, WhatsApp's backend server sends the message content to APNs (for iOS devices) or FCM (for Android devices) using the user's device token. The operating system then displays a notification on the user's device, prompting them to open the app.

Cloud Services for Push Notifications:

For scalable and reliable push notification delivery, cloud services like Tencent Cloud's Mobile Push can be used. It provides a unified platform to send notifications to iOS, Android, and other platforms, simplifying the management of device tokens and message delivery. It also offers features like message targeting, analytics, and A/B testing to optimize notification strategies.