Top 20+ Postman Interview Questions and Answers

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If you are preparing for an interview focused on API testing, understanding Postman is essential. Postman is a widely-used tool for testing, debugging, and documenting APIs, making it popular among developers and QA professionals. In this blog, we have compiled the top 20+ Postman interview questions to help you get ready. 

These questions cover essential concepts, practical examples, and common scenarios that interviewers frequently ask. 

Fun Fact: Postman API Platform is used by many leading companies, including 98% of Fortune 500 organizations.

Postman Interview Questions for Freshers

Here is a list of basic Postman interview questions and answers for freshers: 

1. What is Postman, and why is it used in API testing?

Postman is a popular API testing tool used by developers and testers to send API requests, validate responses, and automate tests. It simplifies API development with features like collections, scripting, and environment variables.

2. How do you create a new request in Postman?

To create a new request in Postman:

• Open Postman and click on New Request.
• Choose the HTTP method (GET, POST, etc.).
• Enter the API endpoint URL.
• Add headers, query parameters, or body content if needed.
• Click Send to execute the request.

3. What are the different HTTP methods in Postman, and what do they do?

• GET – Retrieves data from a server.
• POST – Sends data to create a resource.
• PUT – Updates an existing resource.
• PATCH – Partially updates a resource.
• DELETE – Removes a resource from the server.

4. How can you send query parameters in a GET request using Postman?

In Postman, you can add query parameters by clicking on the Params tab in the request window. Enter the key-value pairs, and Postman appends them to the URL automatically.

5. What is the purpose of collections in Postman?

A collection in Postman is a group of saved API requests that can be organized, shared, and run in an automated sequence. It helps testers manage APIs efficiently.

Note: If you don’t have any Postman interview experience, these questions will help you prepare.

Postman Interview Questions for Experienced

Here are some important Postman tool interview questions and answers for experienced candidates: 

6. How do you use environment variables in Postman?

Environment variables store reusable values like API base URLs or authentication tokens. You can define them under Environments, then reference them using {{variable_name}} in requests.

7. What are Pre-request Scripts and Test Scripts in Postman?

• Pre-request scripts run before sending a request and are used for setting variables, generating timestamps, or authentication.
• Test scripts run after a response is received and help validate API responses using JavaScript.

8. How do you handle authentication in Postman?

Postman supports various authentication methods, including:

• Basic Auth – Username and password.
• Bearer Token – OAuth 2.0 or API tokens.
• API Key – Sent in headers or as a query parameter.
  Authentication details can be set under the Authorization tab.

9. What is the difference between local, global, and environment variables in Postman?

• Local variables exist only within a request.
• Global variables are available across all requests in Postman.
• Environment variables are specific to a defined environment and can change based on the setup.

10. How can you automate API testing in Postman using Newman?

Newman is Postman’s command-line tool that runs collections and automates testing. To execute tests:

1. Install Newman using npm install -g newman.
2. Export the Postman collection.
3. Run newman run collection.json.
4. View the test results in the console.

Newman also supports advanced features like running tests with environment variables and generating detailed reports, which can be integrated into CI/CD pipelines for continuous testing.

Postman Interview Questions for QA

If you are applying for a QA role, you might come across Postman testing interview questions like these: 

11. How do you validate API responses in Postman?

Postman uses JavaScript-based test scripts to validate responses. Under the Tests tab, you can write assertions like:

pm.test(“Status code is 200”, function () {

    pm.response.to.have.status(200);

});

This checks if the response status code is 200.

12. How can you perform data-driven testing in Postman?

Postman allows data-driven testing using external CSV or JSON files. You can:

1. Prepare a CSV/JSON file with test data.
2. Use pm.iterationData.get(“key”) to retrieve values.
3. Run the collection with data using Newman:

newman run collection.json -d data.csv

Advanced Postman API Interview Questions

Let’s go through advanced-level API Postman interview questions and answers: 

13. What are monitors in Postman, and how do they work?

Monitors in Postman run collections on a schedule to check API performance and reliability. They execute tests in the cloud and provide reports on failures.

14. How do you write custom assertions in Postman using JavaScript?

Custom assertions can be written under the Tests tab using JavaScript.

Example:

pm.test(“Response contains expected data”, function () {

    var jsonData = pm.response.json();

    pm.expect(jsonData.name).to.eql(“John Doe”);

});

This verifies that the name field in the response matches “John Doe”.

Postman API Testing Interview Questions

Here are is a list of common interview questions on API testing using Postman: 

15. How can you test RESTful APIs using Postman?

• Select the appropriate HTTP method.
• Enter the API endpoint.
• Add headers, query parameters, or body content.
• Click Send and verify the response, status code, and headers.
• Use test scripts to validate response data.

16. What is the difference between SOAP and REST APIs, and how can you test both in Postman?

• REST APIs use JSON/XML, are lightweight, and follow HTTP methods.
• SOAP APIs use XML and follow strict message formats.
  Postman supports both, allowing you to send requests with XML for SOAP APIs and JSON for REST APIs.

17. How do you debug API requests and responses in Postman?

Postman provides tools for debugging:

• Console – Logs request/response details (View > Show Postman Console).
• Test scripts – Log variables using console.log(variable).
• Postman Interceptor – Captures network traffic for troubleshooting.

18. What are status codes in API testing, and what do common ones like 200, 400, and 500 mean?

This is one of the most common API testing with Postman interview questions for freshers. 

Status codes indicate the result of an API request:

• 200 OK – Success.
• 201 Created – Resource created.
• 400 Bad Request – Invalid request.
• 401 Unauthorized – Missing or incorrect authentication.
• 403 Forbidden – No permission.
• 500 Internal Server Error – Server-side issue.

19. How does Postman’s AI Agent Builder enhance API development?

Postman’s AI Agent Builder simplifies the creation of AI-driven agents and workflows, allowing developers to automate complex tasks and improve API integration.

20. What is Postbot, and how can it assist in API testing?

Postbot is an AI-powered assistant in Postman that helps users by generating test scripts, automating documentation, debugging API requests, and visualizing responses.

Also Read - Top 50+ REST API Interview Questions and Answers

Manual API Testing Using Postman Interview Questions

Here are some manual API testing using Postman interview questions and answers: 

21. How do you test an API manually in Postman without writing scripts?

• Open Postman and create a new request.
• Choose the HTTP method and enter the API URL.
• Add headers, parameters, or body data if required.
• Click Send and review the response status, body, and headers.

22. What is the difference between manual and automated API testing in Postman?

• Manual Testing – Requests are sent manually, and responses are checked visually.
• Automated Testing – Uses test scripts and Newman to validate responses programmatically.
  Automation is preferred for large-scale or repetitive API testing.

Also Read - Top 45 Quality Assurance Interview Questions and Answers

Wrapping Up

These 20+ Postman interview questions and answers will help you prepare for your next API testing interview. Whether you are a fresher or an experienced professional, understanding Postman’s features and functionalities is essential for API testing and development. Practising these questions will give you the confidence to tackle real-world scenarios. Looking for IT jobs in India, including roles that require Postman skills? Visit Hirist, an online job portal where you can easily find the best opportunities.