RabbitMQ

RabbitMQ is a message broker implementing the AMQP 0-9-1 protocol, routing messages from producers to consumers through exchanges, queues, and binding keys with acknowledgements and prefetch control. It adds durable and quorum queues, dead lettering, lazy queues for large backlogs, a management interface for inspecting queues, and plugins that extend it with clustering and federation.

It fits work queues, task distribution, and decoupled service pipelines where delivery guarantees matter.

Running the broker on your own servers on your own infrastructure keeps payloads inside your network, avoids per-message broker fees, and lets you snapshot queues and definitions as part of your restore plan.