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.