RabbitMQ is a commonly used open-source enterprise service bus for publishing and subscribing events.  Connections to RabbitMQ can be created, updated, removed, and tested using the following UI:

To learn more about RabbitMQ, visit the product site at https://www.rabbitmq.com

Publishing messages to RabbitMQ

For testing purpose, messages can be published to RabbitMQ using the following user interface: