? Introduction to Postman

? Quick Overview

Postman is a popular API development and testing tool used by developers and testers to build, test, and document APIs. It provides a simple graphical interface to send HTTP requests and analyze responses without writing extensive code.

? Key Concepts

• API (Application Programming Interface)
• HTTP methods like GET, POST, PUT, DELETE
• Request and Response cycle
• Collections and Environments
• API testing and automation

? History of Postman

Postman started in 2012 as a Chrome browser extension developed to simplify API testing. Over time, it evolved into a full-featured desktop application supporting collaboration, automation, monitoring, and documentation of APIs.

? Role of Postman in API Testing

• Manually test APIs without writing code
• Validate API responses and status codes
• Automate API test cases
• Share API collections with teams
• Generate API documentation automatically

? Syntax / Theory

Postman sends HTTP requests to API endpoints and displays responses such as JSON or XML. Each request consists of:

• Request URL
• HTTP Method
• Headers
• Parameters
• Body (for POST/PUT requests)

? Code Example

// Example of a basic GET request using Fetch API (similar to Postman GET)
fetch("https://api.example.com/users")
.then(response => response.json())
.then(data => console.log(data));

? Live Output / Explanation

? Interactive Example

Using Postman, you can interactively modify headers, parameters, and request bodies and instantly see changes in the response. This makes it ideal for learning and debugging APIs.

? Use Cases

• Testing REST APIs during development
• Debugging backend services
• Automating regression tests
• Collaborating on API design