PushSharp is a server-side library that sends push notifications to iOS, Android, Windows, and other device platforms through their respective cloud messaging services. It provides a unified interface for delivering notifications across Apple Push Notification Service, Firebase Cloud Messaging, Amazon Device Messaging, Blackberry Push Service, Firefox OS Push Service, and Windows Push Notification Service.
The library handles the complexities of push notification delivery through an asynchronous message queue that processes, batches, and retries notifications while respecting each platform's API rate limits. It manages device token lifecycles by querying cloud feedback services to identify and remove expired or invalid tokens, and processes delivery reports to maintain clean recipient lists. Certificate-based authentication is supported for Apple services, and multicast delivery allows sending a single notification payload to multiple devices simultaneously.
PushSharp abstracts platform-specific push notification APIs into a common interface, enabling developers to send notifications to multiple platforms from a single codebase. It supports sending toast notifications to Windows devices and handles the full lifecycle of notification delivery, from queuing through feedback processing.