Publish-Subscribe System

A Publish-Subscribe (Pub-Sub) system is a messaging pattern where "publishers" send messages about specific topics without knowing who will receive them, while "subscribers" express interest in certain topics to receive relevant updates. It's like a newspaper subscription: publishers produce content on various subjects, and subscribers choose which subjects they're interested in. This system allows for flexible, scalable communication, enabling multiple parties to exchange information efficiently without direct connections. It's commonly used in real-time applications like notifications, news feeds, and event-driven systems.