REST API Fundamentals and Design Principles

REST (Representational State Transfer) is the architectural style that powers most modern web APIs. It provides a scalable and standardized way for clients and servers to communicate. Whether we’re building APIs for web applications, mobile apps, or third-party integrations, following RESTful principles helps keep things clear, efficient, and maintainable.

In this lesson, we’ll explore the core principles of REST and understand how to design RESTful APIs effectively.

What is an API?

An API (Application Programming Interface) allows different software applications to communicate with each other. It defines a set of rules for how requests and responses should be structured, enabling seamless interaction between systems.

A useful analogy is a restaurant:

• The menu is the API—it tells customers (clients) what they can order.

• The kitchen is the server—it prepares the food (data) requested.

• The waiter acts as the API itself—taking requests, retrieving data from the kitchen, and delivering responses.

APIs come in many forms, including REST APIs, which are widely used for web-based interactions. REST provides a structured way for clients to request and manipulate data over the web.