API Testing

API Testing is a critical part of software testing that validates communication between frontend, backend, databases, and third-party services. API Testing helps to identify defects early, even before they appear in the UI. Since it directly tests the service layer, it requires fewer steps compared to UI testing and makes debugging faster and more efficient.

As a software tester, you need to be good at both UI and API testing. This helps in creating better test strategies, writing effective test plans, analyzing the root cause of defects, and improving overall test coverage.

This tutorial is designed for beginners and for anyone who wants to understand API Testing from scratch. In this tutorial, we will learn what an API is, important HTTP concepts, request and response formats, validations, authentication methods, security checks, Postman basics, and execution methods. Each topic is structured in a simple order so that you can build a strong foundation in API Testing.