What is an API ? | Explained in easy language!!

An Application Programming Interface (API) is the entire business logic of software exposed to the outside world. In other words, it is the overall accessible functionality of the program minus the user interface.

API’s are great because they help outside programmers to build their own custom user interfaces and implement the existing business logic of applications rather than reinventing the whole software.

{ये एक ऐसा Software Code है जो की अलग अलग Software Program को आपस में communicate करने में मदद करता है.}[API helps to interact between two applications/codes/web applications or share data between them which is useful for them]

Like many weather forecasting Company have API. It means if I want to make a python program in which weather conditions are shown of that place (i am not going to update each time weather changes and for every place on earth instead I will fetch data from other sources) so for that, I can use API of a company which have that feature 

One more example goes here -->

     I am making a website for a client in which there is a requirement for user login  and my client wants a feature in which a user can login with his Facebook ID; so what I am going to do is to get an API feature from developers.facebook.com and get the API and take the Facebook data for my website login function 

It means my website's server directly talk to Facebook's server with a request to create an event Your server would then receive facebook's response, process it, and send back relevant information to the browser, such as a confirmation message to the user.

To interact through API we need an API key as authentication with the API provider