Higher-layer APIs are focused on widgets and the overall layout and behavior of a graphical user interface. Working at this level, a developer wouldn't expect to be dealing with buffers and events but with high-level concepts such as buttons, text areas, and layouts. The types and functions defined at this layer (within the widget package) are designed to be easy to understand from a high level and includes graphical user interface concepts that will be familiar to most developers.

The Shiny widgets (detailed further in the Widgets and material design section later in this chapter) are all written in pure Go and encapsulate any widget logic (such as input handling), as well as rendering (by implementing the node.PaintBase() or node.Paint() functions). This allows the user interface code to remain completely detached from the drivers for better testing and to promote consistency across all supported operating systems.