You are building a multi-tenant SaaS platform that sends push notifications for each customer's mobile app. Each customer brings their own APNs/FCM credentials and requires isolation of registrations and tags. You want to minimize operational overhead while keeping environments (Dev/Test/Prod) separate. What Azure Notification Hubs design should you implement?

The correct approach is to create one Notification Hubs namespace per environment (Dev/Test/Prod) for logical separation. Within each namespace, create a separate Notification Hub for each customer application. This design allows you to configure each customer's specific APNs/FCM credentials directly within their dedicated hub, ensuring strong isolation of credentials and registrations. Tags can then be used within each customer's hub for fine-grained targeting of notifications (e.g., to specific user segments). This minimizes operational overhead by leveraging Notification Hubs' built-in credential management and push capabilities. Incorrect options: A single hub with multiple credential sets is not supported directly for APNs/FCM, as a hub is typically configured with one set of credentials per platform. Creating one hub per platform shared by all customers would not allow for per-customer credential management and would complicate isolation. Replacing Notification Hubs with Event Grid and Web Push is a different technology stack and doesn't directly address APNs/FCM push notifications for mobile apps. Azure SignalR Service is for real-time web functionality, not for sending push notifications to native mobile platforms via APNs/FCM.