RabbitMQ

RabbitMQ is an open-source message broker that implements the AMQP protocol along with several others (MQTT, STOMP). Where Kafka is a log-oriented streaming platform, RabbitMQ is a flexible message router optimised for traditional work queues, RPC, and complex routing topologies.

Core concepts

• Producer. Publishes messages to an exchange.
• Exchange. Routes messages to queues via bindings; types include direct, topic, fanout, headers.
• Queue. A buffer that holds messages; consumers subscribe and receive in FIFO order.
• Binding. A rule that connects an exchange to a queue, often with a routing key pattern.
• Acknowledgement. Consumers ack messages after processing; un-acked messages are redelivered after timeout.

Routing patterns

• Direct. Routing key must match exactly.
• Topic. Routing key matches a pattern with wildcards (orders.*.created).
• Fanout. Broadcast to every bound queue.
• Headers. Route by message header values rather than routing key.

RabbitMQ vs Kafka

• RabbitMQ. Lower latency, complex routing, traditional work queues, RPC patterns. Messages are removed after consumption.
• Kafka. Higher throughput, durable append-only log, replay, stream processing. Messages persist for a configured retention period.