hwat is an api 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: what is api

It means connectivity. 
I mean API is the messenger that takes requests and 
tells a system what you want to do and then returns the response back to you
What is JSON? JavaScript Object Notation 
It's a key value pair. its popular light-weight way of transferring data
What is Postman is a Client tool to work with APIs 
to send requests get response. Organize the requests  
Collection in Postman is a top level folder 
Header: exists in both request and response, 
is metadata about the request. It's a key value pair 
Content Type: in request header: to specify what kind of data 
we are sending to the server 
in response header: what was the contenttype we got as response

Example 3: what is an api

An application programming interface (API) is a computing interface which
defines interactions between multiple software intermediaries.

It defines the kinds of calls or requests that can be made, how to make them,
the data formats that should be used, the conventions to follow, etc.