What is Pub/Sub?

Publish-subscribe (or pub/sub) is a messaging pattern where senders of messages, called publishers, do not program the messages to be sent directly to specific receivers, called subscribers. Instead, published messages are categorized into channels, without knowledge of what (if any) subscribers there may be. Subscribers, in turn, express interest in one or more channels and only receive messages that are categorized in channels of interest. This decoupling of publishers and subscribers allows for greater scalability and flexibility in distributed systems. It is commonly used in event-driven architectures, real-time data streaming, and asynchronous communication between microservices.