API stands for Application Programming Interface, this interface allows two mobile applications to communicate with each other. This ensures smooth connectivity in the whole mobile framework. This improves the responsiveness of the whole mobile.
It is also used by mobile app developers, customized APIs can be bought with relevance to the needs of the developers and the users. When you buy an API you also receive an API key you can only access an API if you have the key. This promotes safety and privacy.
Some famous and well-known APIs include Facebook API, Twitter API, Google Maps API, YouTube Data API, etc.