Introduction: Growing Fresher Hiring Demand in Testing

With the rapid growth of web and mobile applications, API testing has become one of the most in-demand skills for software testing freshers. Companies today build applications using multiple services that communicate with each other through APIs. Because of this, organizations actively hire freshers who understand basic API concepts, testing logic, and real-world scenarios.

Many freshers worry that API testing is too technical. The truth is, interviewers focus on clarity, fundamentals, and logical thinking, not deep coding. Preparing the right api testing interview questions for freshers can help you stand out even with zero industry experience.

This article explains everything step by step, using simple language, real examples, sample test cases, and bug reports, making it perfect for beginners.

What Is Software, Manual, and Automation Testing? (Simple Explanation)

What Is Software Testing?

Software testing is the process of checking whether an application works correctly and meets user requirements.

Example:
If a login feature allows users to log in with an incorrect password, testing helps identify and fix this issue.

What Is Manual Testing?

Manual testing is testing software without using automation tools.

Examples:

Checking API responses manually using tools
Verifying error messages
Validating response data

Manual testing is the foundation for API testing freshers.

What Is Automation Testing?

Automation testing uses tools or scripts to execute test cases automatically.

Simple Example:
Instead of sending the same API request 100 times manually, automation runs it automatically.

For freshers, concept understanding matters more than automation skills.

What Is API Testing? (For Beginners)

API (Application Programming Interface) allows two software systems to communicate with each other.

Simple Explanation

When you log in to an app:

The UI sends a request to the API
The API processes it
The API returns a response (success or failure)

API testing checks:

Requests
Responses
Data accuracy
Error handling

API Testing Interview Questions for Freshers (With Answers)

Below are 60+ api testing interview questions for freshers, starting from very basic to slightly advanced.

Basic API Testing Interview Questions

1. What is an API?

An API is a set of rules that allows applications to communicate with each other.

2. Why is API testing important?

API testing ensures data accuracy, system reliability, and faster bug detection.

3. What is an API request?

A message sent to the server asking for data or action.

4. What is an API response?

The reply sent by the server after processing the request.

5. What are common API methods?

GET – retrieve data
POST – create data
PUT – update data
DELETE – remove data

Freshers QA Interview Q&A – API Basics

6. What is REST API?

REST API follows simple rules using HTTP methods.

7. What is SOAP API?

SOAP API uses XML format and strict rules.

8. Difference between REST and SOAP?

REST is lightweight
SOAP is more secure but complex

9. What is endpoint?

A specific URL where API requests are sent.

10. What is payload?

The data sent in an API request or response.

Manual API Testing Interview Questions

11. How do you test an API manually?

Using tools like Postman by sending requests and validating responses.

12. What is status code?

A number that indicates request result.

13. Common HTTP status codes?

200 – Success
400 – Bad request
401 – Unauthorized
404 – Not found
500 – Server error

14. What is header in API?

Metadata like authentication, content type.

15. What is JSON?

A simple data format used in API responses.

Simple Automation Interview Questions for API Testing

16. Can API testing be automated?

Yes, using tools like Postman, Rest Assured.

17. Is coding mandatory for API testing?

Basic scripting helps, but logic is more important for freshers.

18. What is collection in Postman?

A group of API requests.

19. What is environment in Postman?

A place to store variables like URLs and tokens.

20. What is token?

A security key used for authentication.

Scenario-Based API Testing Questions for Freshers

21. How will you test a login API?

Valid credentials
Invalid credentials
Blank fields
Token generation

22. How will you test invalid API request?

Send incorrect data and verify error message.

23. What if API returns wrong data?

Log defect with request and response details.

24. How do you test API performance?

Check response time under load.

25. How do you validate API security?

Test unauthorized access scenarios.

Sample Test Cases for Freshers

Login API Test Case Example

Field	Details
Test Case ID	TC_API_Login_01
Scenario	Verify login with valid credentials
Request	POST
Input	Valid username & password
Expected Result	Status 200, token generated
Status	Pass

Mobile App API Test Case Example

Scenario: Verify product list API

Send GET request
Verify response code
Validate product count
Check response time

UI + API Test Case Example

Scenario: Verify UI reflects API data

Call API
Validate response
Check UI displays same data

Bug Report Writing Examples for Freshers

Sample API Bug Report

Bug ID: API_201
Title: Login API returns success for invalid password
Environment: QA
Steps to Reproduce:

Send login API with wrong password
Observe response

Expected Result: Error message with 401
Actual Result: Status 200 received
Severity: High
Status: New

Tips to Answer Confidently in API Testing Interviews

Explain concepts using simple examples
Don’t use complex words unnecessarily
Mention tools only if asked
Focus on request–response logic
Think like a user and tester

Interviewers prefer clarity over complexity.

Quick Revision Sheet (One-Glance Summary)

API connects systems
Request → Process → Response
Status codes indicate result
Validate data, errors, and security
Manual testing basics are essential

FAQs – API Testing Interview Questions for Freshers

Q1. Is API testing hard for freshers?

No, understanding basics makes it easy.

Q2. Do I need coding knowledge?

Basic scripting helps, but not mandatory.

Q3. Which tool is best for beginners?

Postman is ideal for freshers.

Q4. Is API testing manual or automation?

It can be both.

Q5. What should freshers focus on first?

API concepts, scenarios, and test cases.