what is a rest api and how does it work code example

Example 1: REST API

[{"id":1,"username":"admin","email":"[email protected]"},{"id":2,"username":"Vagner","email":"[email protected]"},{"id":3,"username":"Administrator","email":"[email protected]"}]

Example 2: what is a REST API

An endpoint is one end of a communication channel. 
it would be represented as the URL of a server or service.
In REST APIs, the resource typically refers to some object or set of objects 
that are exposed at an API endpoint. 
An endpoint by itself is just 
a reference to a URL that accepts web requests that may or may not be RESTful.