Sling instances tend to live in herds. Synchronizing content among them is quite easy, as the whole repository is available via the REST API. However, sending control messages ("create a user", "give me a list of modified pages") may be tricky. There is a better way than implementing dozens of servlets or event listeners: it is a message queue. During the presentation we will show how to integrate ActiveMQ with Sling and how to use it to exchange messages between instances. We will also present some real-world use cases.