Azure Notification Hubs provide an easy-to-use, multiplatform, scaled-out push infrastructure that enables you to send mobile push notifications from any backend (in the cloud or on-premises) to any mobile platform.
With Notification Hubs you can easily send cross-platform, personalized push notifications, abstracting the details of the different platform notification systems (PNS). With a single API call, you can target individual users or entire audience segments containing millions of users, across all their devices.
You can use Notification Hubs for both enterprise and consumer scenarios. For example:
Send breaking news notifications to millions with low latency (Notification Hubs powers Bing applications pre-installed on all Windows and Windows Phone devices).
Send location-based coupons to user segments.
Send event notifications to users or groups for sports/finance/games applications.
Notify users of enterprise events like new messages/emails, and sales leads.
Send one-time-passwords required for multi-factor authentication.
Smartphones and tablets have the ability to "notify" users when an event has occurred. These notifications can take many forms.
In Windows Store and Windows Phone applications, the notification can be in the form of a toast: a modeless window appears, with a sound, to signal a new notification. Other notification types are supports including tile, raw, and badge notifications. For more information on the types of notifications supported on Windows devices see, Tiles, Badges, and Notifications.
On Apple iOS devices, the push similarly notifies the user with a dialog box, requesting the user to view or close the notification. Clicking View opens the application that is receiving the message. For more information on iOS Notifications see, iOS Notifications.
Push notifications help mobile devices display fresh information while remaining energy-efficient. Notifications can be sent by backend systems to mobile devices even when corresponding apps on a device are not active. Push notifications are a vital component for consumer apps, where they are used to increase app engagement and usage. Notifications are also useful to enterprises, when up-to-date information increases employee responsiveness to business events.
Some specific examples of mobile engagement scenarios are:
Push notifications are delivered through platform-specific infrastructures called Platform Notification Systems (PNS). A PNS offers barebones functions (that is, no support for broadcast, personalization) and have no common interface. For instance, in order to send a notification to a Windows Store app, a developer must contact the WNS (Windows Notification Service), to send a notification to an iOS device, the same developer has to contact APNS (Apple Push Notification Service), and send the message a second time. Azure Notification hubs help by providing a common interface, along with other features to support push notifications across each platform.
At a high level, though, all platform notification systems follow the same pattern:
While these systems are very powerful, they still leave much work to the app developer in order to implement even common push notification scenarios, such as broadcasting or sending push notifications to a user.
Push notifications are one of the most requested features in cloud services for mobile apps. The reason for this is that the infrastructure required to make them work is fairly complex and mostly unrelated to the main business logic of the app. Some of the challenges in building an on-demand push infrastructure are:
Platform dependency. In order to send notifications to devices on different platforms, multiple interfaces must be coded in the back-end. Not only are the low-level details different, but the presentation of the notification (tile, toast, or badge) is also platform-dependent. These differences can lead to complex and hard-to-maintain back-end code.
Scale. Scaling this infrastructure has two aspects:
Routing. PNSs provide a way to send a message to a device. However, in most apps notifications are targeted at users and/or interest groups (for example, all employees assigned to a certain customer account). As such, in order to route the notifications to the correct devices, the app back-end must maintain a registry that associates interest groups with device tokens. This overhead adds to the total time to market and maintenance costs of an app.
Notification Hubs eliminate complexity: you do not have to manage the challenges of push notifications. Instead, you can use a Notification Hub. Notification Hubs use a full multiplatform, scaled-out push notification infrastructure, and considerably reduce the push-specific code that runs in the app backend. Notification Hubs implement all the functionality of a push infrastructure. Devices are only responsible for registering PNS handles, and the backend is responsible for sending platform-independent messages to users or interest groups, as shown in the following figure:
Notification hubs provide a ready-to-use push notification infrastructure with the following advantages:
Works with any back-end: Cloud or on-premises, .NET, PHP, Java, Node, etc.
Scale. Notification hubs scale to millions of devices without the need to re-architect or shard.
Rich set of delivery patterns:
Each device, when sending its handle to a notification hub, can specify one or more tags. For more information about tags. Tags do not have to be pre-provisioned or disposed. Tags provide a simple way to send notifications to users or interest groups. Since tags can contain any app-specific identifier (such as user or group IDs), their use frees the app back-end from the burden of having to store and manage device handles.
Personalization: Each device can have one or more templates, to achieve per-device localization and personalization without affecting back-end code.
Security: Shared Access Secret (SAS) or federated authentication.
Rich telemetry: Available in the portal and programmatically.
You can find out more about Notification Hubs in these topics:
The relevant .NET managed API references for push notifications are located here: