An Application Programming Interface (API) is a set of routines, protocols, and tools that say how different software components should interact with each other. A good API allows for efficient development of the software as building blocks. Applications can be complex to navigate and use, especially if the application can be used across various devices, each with their different architectures. APIs are meant to simplify usage of the application by highlighting its defining features.

API exists in many different forms. Some API exist as purely software interactions; others can exist as bridges between software and hardware. The ultimate takeaway from APIs is that they provide an easy-to-use interface to operate a complex system or program. Does that mean APIs are necessary? Not at all, but they make things easier.