RabbitMQ
The RabbitMQ plugin creates and manages named RabbitMQ connections for your application. It is built on amqp-connection-manager, so connection URLs, manager options, reconnection behavior, and channel usage follow that library. See its documentation for details on using the connection manager directly.
Kafka
The Kafka plugin creates named KafkaJS clients and manages a producer and consumer for each connection. It passes each connection's Kafka configuration to KafkaJS and connects configured producers and consumers during plugin registration. See the KafkaJS documentation for Kafka concepts and the full client API.