Pushsystem

Push system, or push-based data distribution, is a model in which information updates are proactively delivered by a server to clients without each client requesting the data. In a push system, publishers or brokers determine when data is available and push it to subscribers or devices, often via a central server, a pub/sub broker, or a notification service. The approach contrasts with pull systems, where clients request updates on demand.

Common implementations include mobile push notification services, such as Apple Push Notification Service (APNS) and Google Firebase Cloud Messaging (FCM), server-sent events, WebSocket-based channels, and email distribution lists. In publish/subscribe architectures, publishers publish messages to topics and subscribers receive messages for topics to which they have subscribed. Push systems may maintain state, handle backpressure, and support offline clients by queuing messages for later delivery.

History and scope have evolved from early broadcast-style methods to modern real-time web and mobile applications. Security and privacy considerations are central, including proper authentication and authorization, opt-in versus opt-out policies, rate limiting, and encryption for data in transit.

Advantages of push systems include reduced latency for recipients, timely delivery of alerts, and decreased polling overhead for clients and servers. Disadvantages include potential wasted delivery when recipients are offline or disengaged, notification fatigue, scalability challenges, and privacy concerns related to subscription data management.

See also: pull system, publish/subscribe, notification services, server-sent events, Web Push.