Lecture 6: Understanding REST APIs

REST API Development: Build, Test, Troubleshoot

REST APIs are one of the most widely used technologies for communication between modern software systems. They allow applications to exchange data in a standardized way using the HTTP protocol.

Understanding how REST APIs work is essential for developers who build web applications, mobile applications, cloud services, or system integrations.

What Is a REST API?

A REST API (Representational State Transfer Application Programming Interface) is an interface that allows software applications to communicate with each other using HTTP requests.

Instead of interacting directly with a database, external systems send requests to an API endpoint. The API processes the request, retrieves or modifies data, and returns a response.

The server may return a JSON response like this:

Core Components of a REST API

• Client: The application that sends the request (browser, mobile app, system).
• Server: The system that processes the request and returns a response.
• Endpoint: The URL where the API can be accessed.
• HTTP Methods: Actions performed on resources such as GET, POST, PUT, and DELETE.
• Data Format: Most APIs return data in JSON format.

Resources and Endpoints

In REST architecture, everything is treated as a resource. A resource could represent a customer, product, order, or any data entity.

Resources are accessed through endpoints such as:

Each endpoint represents a collection or a specific resource within the system.

Common HTTP Methods Used in REST APIs

• GET – Retrieve information from the server
• POST – Create new records
• PUT – Update existing records
• DELETE – Remove records

These methods allow clients to perform operations on resources while keeping the API structure clean and consistent.

Why REST APIs Are So Popular

• They are simple and easy to implement
• They work with nearly any programming language
• They are scalable and efficient
• They enable integration between different systems
• They are the foundation of modern web services

Because of these advantages, REST APIs are used in cloud services, mobile applications, e-commerce platforms, financial systems, and countless other modern technologies.

What You Will Do Next

In the following lectures, you will begin exploring how to configure a REST API environment, create API projects, define models, and start implementing real API endpoints that interact with a database.

This hands-on approach will help you move from understanding the theory of REST APIs to building fully functional APIs yourself.