Scenarios of data exchange in a system landscape are described, and XML is presented in detail as an example technology for data exchange formats. After introducing the elementary concepts of XML, namely, elements and attributes, namespaces and the data type definition using XML Schema are discussed. As an alternative, JSON is briefly described. It is reflected on what insights can be drawn from the “XML case study” for integration through data exchange. A message broker is a special communication channel that is used in particular for data exchange. We look at associated concepts such as asynchronous communication and the publish-and-subscribe principle.