RabbitMQ
In depthPlatform
Reliable open-source message broker supporting multiple protocols (AMQP, MQTT, STOMP).
RabbitMQ, explained
Written by EduVerseWhat it is
RabbitMQ is an open-source message broker. A producer publishes a message to an exchange, the exchange routes it to one or more queues based on rules called bindings, and a consumer picks it up and acknowledges it once the work is done.
Why teams use it
It’s a good fit for background jobs: sending emails, generating PDFs or resizing images, spread over several workers, with a retry when one fails. Next to Kafka it’s simpler to start with and routes messages more flexibly, but messages normally disappear once acknowledged, so it isn’t built for replaying history.
An example from work
Users stop getting welcome emails. In the RabbitMQ management UI you open the email queue and see thousands of messages under Ready and zero consumers, because the worker crashed after a deploy. Once you restart it, the Ready count drops back to zero.
Our own explanation, not a quote from the book.
In the book
Sentences from The Software Realm, Decoded that mention RabbitMQ, exactly as printed.

Peter “I keep hearing about Kafka and RabbitMQ.”
Chapter 8 · 8.4 Kafka vs. RabbitMQ: Recording vs. Mailbox · p. 189Open in the free preview
2 more passages about RabbitMQ in the full book
Read every conversation where RabbitMQ comes up, with the interactive slides and demos.
Where it fits
Message queues, task distribution, decoupling services
Coverage in the book
Covered in depth: multiple pages with explanations, examples and simulations.