A message broker is a middle tool that helps different parts of a system talk to each other by passing messages between them. It makes sure messages get delivered even if the sender and receiver aren't ready at the same time.

How it works

One part of a program sends a message to the broker. The broker holds it, stores it, and then delivers it to the right receiver when it's ready. This way, the sender and receiver don't have to connect directly or work at the same speed.

Analogy

It's like a post office. You drop off a letter there (the message), and the post office makes sure it gets to the right person. The receiver doesn't need to be home right now - the message will be delivered when they are ready.