1.  Introduction to REST API Testing 1.1. What is an API? An API (Application Programming Interface) defines the methods, protocols, and tools for building software applications. It specifies how different software components should interact with each other. In our social media application, the API provides a set of endpoints and rules for accessing and manipulating user profiles. The API documentation defines the available endpoints, the required parameters, the expected response format, and any authentication requirements. Developers can use this API to integrate social media features into their own applications. Table of Contents: 1. Introduction to REST API Testing      1.1. What is an API?      1.2. What is REST API?      1.3. What is SOAP API?      1.4. Why Test APIs?      1.4. Challenges in API Testing 2. Key Concepts in REST API Testing      2.1. HTTP Methods (GET, POST, PUT, DELETE)      2.2. URI (Uniform Resource Identifier)      2.3. Request Headers      2.4. Request Bod