What are Event Brokers?
An event broker is middleware that mediates the communication of event messages between producers and consumers using the various message exchange patterns. Event-driven architecture (EDA) uses event brokers to provide the messaging infrastructure.
Applications that produce and consume events are clients of an event broker. When an application publishes an event message, the event is sent to an event broker, which then routes the event on to subscribing clients.
An event broker can be a hardware appliance, software, or software-as-a-service (SaaS).
Now that you know what event brokers are, lets move on to Understanding Topics.