API Testing with Postman Course in Chennai

API testing involves verifying the functionality, reliability, and security of Application Programming Interfaces. It ensures that APIs respond correctly to requests, handle errors gracefully, and integrate well with other systems, which is critical for seamless software communication.

Common HTTP methods include GET (fetch data), POST (create new data), PUT (update existing data), PATCH (partial update), and DELETE (remove data). Each method performs a specific action on the server resource.

You can write test scripts in JavaScript inside Postman to check the response status code, body content, response time, or specific JSON properties, using assertions to automate validation.

Environment variables store dynamic data like URLs, tokens, or user IDs, which allows running the same tests in different environments (development, staging, production) without changing the request manually.

Postman supports various authentication methods such as Basic Auth, Bearer Tokens, OAuth 2.0, and API keys, which you can configure in the Authorization tab to test secured APIs.

200 OK means the request succeeded, and the server returned the requested data. 201 Created indicates that a new resource was successfully created as a result of the request.

You can send input data via the body section using formats like JSON, XML, or form-data, depending on what the API expects. Postman allows you to define this payload easily for POST or PUT requests.

A collection groups multiple API requests together, allowing you to organize, run, and automate tests sequentially or in bulk, making it easier to manage complex API testing workflows.

You can automate tests by writing JavaScript test scripts, grouping requests into collections, and running these collections via Postman Runner or using Newman, the command-line tool, for integration with CI/CD pipelines.