Explaining message queues

Smoke signals, couriers, carrier pigeons, and semaphores: if this was a riddle, the word messages would immediately spring to mind. Humanity has always had the need to connect, finding new ways to defy challenges posed by the distance between the different groups of people needing to communicate. Humankind has come a long way with modern technologies, but essentially, the basics remain. Senders, recipients, and messages are at the core of all our communication infrastructures.

Software applications have the same needs; systems need to communicate and send messages between each other. They sometimes need to be sure that the message that's been sent has reached its destination, and sometimes they need to receive an immediate response. In some cases, they may even need to receive more than one response. Based on these different needs, different styles of communication between systems have emerged.

AMQP, RabbitMQ's default protocol, is explained in the next section.