What Is REST?

In web technology, REST stands for Representational State Transfer. It is an architectural style used for designing networked applications, especially web services. 

Key Concepts of REST:

1. Stateless:
   Each HTTP (Hyper Text Transfer Protocol) request from a client to a server must contain all the information needed to understand and process the request. The server does not store any state about the client session on the server side.

2. Client-Server Architecture:
   The client (e.g., a web browser or mobile app) and the server (e.g., an API service) are separate.

3. Uniform Interface:
   REST uses a consistent and standardized set of operations, typically over HTTP. The main HTTP methods are:

   • GET – retrieve data

   • POST – create new data

   • PUT – update existing data

   • DELETE – delete data

4. Resources:
   REST treats data as resources, which are identified using URLs (Uniform Resource Locators). For example:

   GET https://api.example.com/users/123
   

5. Representation:
   The resource can be represented in multiple formats like JSON, XML, or HTML. JSON (JavaScript Object Notation) is the most commonly used format today in REST APIs.

Example of a RESTful API Interaction:

Imagine a RESTful service that manages books:

• GET /books – returns a list of all books

• GET /books/1 – returns details of the book with ID 1

• POST /books – adds a new book

• PUT /books/1 – updates book with ID 1

• DELETE /books/1 – deletes the book with ID 1

Summary:

REST is a popular and widely used method for building web services due to its simplicity, scalability, and alignment with standard web protocols like HTTP. It’s the backbone of many modern web and mobile apps interacting with cloud APIs.