This chapter briefly covers two main possibilities of adding interactivity to the graphics in a Shiny application: by including interaction possibilities for native R graphics provided by the Shiny package, or by integrating JavaScript-generated visualizations, which can be interactive. Although some of the libraries seen in this book such as googleVis are interactive, their interaction is already specified. For example, on hovering it is not possible on googleVis to do something else different from displaying a tooltip. The two solutions presented here are much more flexible in this sense because the developer can receive the information from the interaction and produce any kind of reaction to it.