is building an api a good project code example

Example 1: what is an api

An application program interface (API) is a set of routines, protocols, and
tools for building software applications.

Basically, an API specifies how software components should interact.
Additionally, APIs are used when programming graphical user interface (GUI)
components.

A good API makes it easier to develop a program by providing all the
building blocks. A programmer then puts the blocks together.

Example 2: why api

It verifies all the functional paths 
of the system under test very effectively.
It provides the most stable interface.
It is easier to maintain and 
provides fast feedback.