In the context of web development, a mashup is a web page or web application that uses content from more than one source to create a single new service displayed in a single graphical interface.
The Capability APIs enable you to easily and quickly integrate with your Qlik Sense objects to produce enriched results that were not necessarily the original reason for producing the source app in Qlik Sense. You can reuse Qlik Sense visualizations, including your custom extensions, and you can also make use of Qlik Sense data and calculations.
By using active content, your visualizations are updated when state changes. You can also subscribe to data and change the state through the visualizations.