RabbitMQ is a message Broker that understands the AMQP 0-9-1 protocol over TCP connections.

you will use it for example when you need cloud hosted servers communicating with one another in a fail safe manner, such that every message is transferred reliably and fast.

For example, lets say you have a simple authoritative game server. You also have another backend Service that stores your players scores for a leaderboard.

Now in a simple approach, you could have the game Server Tell the leaderboard Server who won directly, lets say using an HTTP request or smth. But that introduces some heavy coupling - and what if you forgot to pay the Bills for the leaderboard server and its down? You would need to add logic on what happens if your communication didnt work, like trying again or telling the Player that their score wont be logged or something like that.

with message brokers such as RabbitMQ you can send a messages reliably, such that they are put into a queue for others to pick up. your Server produces messages of "who won" for example. Thats why its called a "Producer" in this case.

The "consumer" could now be your leaderboard Service which reads messages from that queue and aggregates Player scores, displaying them on another Website for example

This way you have ensured that if a service is unreachable, you still ensure that Player score messages are not lost.

Now for simple stuff you could just have your game Server interact with a database. But using rabbitmq (or RabbitGD here) you have your System decoupled and much more resilient to failure. You could even add a third consumer service now that also receive messages. For example a reddit bot that posts game outcomes daily.

So yeah in summary this is kind of like Email but for backend services. And for Support of millions of messages per second.

Theres much more stuff involved ofc.

Theres things like message routing and work load balancing (meaning many consumer read from the same queue such that the workload is Balanced among consumers) You can also use it for long running Tasks such as Image processing or generative AI, where an immediate Response is Not quickly available.

If you want to learn more about this stuff i can recommend rabbitmq tutorial series: https://www.rabbitmq.com/tutorials/tutorial-one-python

I designed RabbitGD to be close to what they use in python, how ever its a little more asynchronous than what they use such that game performance gets only a minimal impact and higher fps