Kivy is actually an API for Python, which lets us create cross-platform apps. An application programming interface (API) is a set of routines, protocols, and tools to build software applications. Generally, we call Kivy as a framework because it also has procedures and instructions, such as the Kv language, which are not present in Python. Frameworks are environments that come with support programs, compilers, code libraries, tool sets, and APIs.

In this chapter, we want to review the Kivy API reference. We will go through some useful classes of the API. Every time we import a Kivy package, we will be dealing with an API. Even though the usual imports are from kivy.uix, there are more options and classes in the Kivy API. The Kivy developers have created the API reference, which you can refer to online at http://kivy.org/docs/api-kivy.html for an exhaustive information.