A cloud messaging service that delivers real-time alerts and messages directly to users' mobile devices, web browsers, or applications — even when the app isn't actively open. Like a digital tap on the shoulder, push notifications enable apps to re-engage users with timely, relevant information. AWS offers Amazon SNS (Simple Notification Service) for mobile push, Azure provides Notification Hubs, GCP has Firebase Cloud Messaging (FCM), and OCI supports notifications through its Notification Service. These platforms handle device registration, message routing, platform-specific formatting (iOS, Android, web), and delivery tracking at massive scale.
A food delivery app sends push notifications to update customers in real time: 'Your order has been picked up by the restaurant,' 'Your driver is 5 minutes away,' and 'Your food has arrived!' The notification hub handles delivering these messages to millions of users simultaneously across iOS, Android, and web, with each platform receiving properly formatted messages.
All four provide managed messaging for sending notifications at scale. SNS can deliver mobile push (and other pub/sub targets), Azure Notification Hubs focuses on cross-platform mobile push with device registration and templates, FCM is Google’s push service for Android/web (and iOS via APNs), and OCI Notifications is a pub/sub notification service commonly used to fan out events (push-to-device typically uses platform-specific services like FCM/APNs via an app/backend).