API Testing Using SoapUI Interview Questions

Introduction – Why API Testing Using SoapUI Is Important in Interviews

In many enterprise projects—especially banking, insurance, telecom, and legacy systems—SOAP and REST APIs are widely used. SoapUI is one of the most popular tools for testing these APIs because it supports both SOAP and REST, advanced assertions, security testing, and automation.

That’s why interviewers often ask api testing using soapui interview questions to evaluate whether a candidate:

• Understands API testing fundamentals
  
• Knows SOAP and REST concepts
  
• Has hands-on experience with SoapUI
  
• Can validate status codes, response data, and schemas
  
• Can explain real-time project scenarios clearly
  

This article is designed for freshers, manual testers, and experienced QA professionals, written in a simple, technical, and interview-focused style.

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What Is API Testing? (Clear & Simple)

API testing is the process of testing Application Programming Interfaces directly to ensure:

• Correct request handling
  
• Accurate response data
  
• Proper business logic execution
  
• Secure access control
  
• Correct error handling
  

Unlike UI testing, API testing:

• Does not depend on UI
  
• Is faster and more stable
  
• Finds defects early in the development cycle
  

Simple Example

For a Fund Transfer API:

• Valid request → 200 OK
  
• Insufficient balance → 400 Bad Request
  
• Invalid account → 404 Not Found
  

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REST vs SOAP vs GraphQL (SoapUI Interview Context)

Feature	REST	SOAP	GraphQL
Data Format	JSON / XML	XML only	JSON
Contract	Optional	Mandatory (WSDL)	Schema
SoapUI Support	Yes	Yes	Limited
Enterprise Usage	High	Very High	Low
Interview Focus	High	High	Low

👉 In api testing using soapui interview questions, SOAP and REST are the main focus.

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API Testing Using SoapUI Interview Questions & Answers (100+)

Section 1: SoapUI & API Basics (Q1–Q20)

1. What is SoapUI?
   SoapUI is an open-source tool used to test SOAP and REST APIs.
   
2. Which APIs can be tested using SoapUI?
   SOAP and REST APIs.
   
3. What is API testing?
   Testing backend services without UI.
   
4. Why is SoapUI popular in enterprise projects?
   Strong SOAP support and advanced assertions.
   
5. What is SOAP?
   A protocol that uses XML for message exchange.
   
6. What is REST?
   An architectural style using HTTP methods.
   
7. What is WSDL?
   Web Services Description Language for SOAP APIs.
   
8. What is an endpoint?
   The URL where an API is exposed.
   
9. What is request payload?
   Data sent to the API.
   
10. What is response payload?
    Data returned by the API.
    
11. What is statelessness?
    Each request is independent.
    
12. What is authentication?
    Verifying user identity.
    
13. What is authorization?
    Verifying user access rights.
    
14. Authentication types in SoapUI?
    Basic Auth, OAuth, API Key.
    
15. What is positive testing?
    Testing with valid input.
    
16. What is negative testing?
    Testing with invalid input.
    
17. What is XML?
    

<user>

  <id>101</id>

  <name>Ramesh</name>

</user>

18. What is JSON?
    

{

  “id”: 101,

  “name”: “Ramesh”

}

19. What is API documentation?
    Instructions on how to use an API.
    
20. What is a test suite in SoapUI?
    A collection of test cases.
    

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HTTP Methods – Common Interview Questions

Method	Purpose
GET	Fetch data
POST	Create data
PUT	Update full resource
PATCH	Update partial resource
DELETE	Remove resource

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HTTP Status Codes – Must-Know for SoapUI Interviews

Code	Meaning	Example
200	OK	Successful GET
201	Created	Successful POST
204	No Content	Successful DELETE
400	Bad Request	Invalid input
401	Unauthorized	Invalid credentials
403	Forbidden	Access denied
404	Not Found	Resource missing
409	Conflict	Duplicate data
422	Validation error	Business rule issue
500	Server Error	Backend failure

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Section 2: SoapUI Features & Validations (Q21–Q50)

21. What validations can be done in SoapUI?
    Status code, response content, headers, schema, time.
    
22. Is checking status code enough?
    No, response data must be validated.
    
23. What is an assertion in SoapUI?
    A rule to validate expected results.
    
24. Types of assertions in SoapUI?
    Contains, XPath, XQuery, Schema, Script.
    
25. What is XPath assertion?
    Used to validate XML nodes.
    
26. What is JSONPath assertion?
    Used to validate JSON responses.
    
27. What is schema validation?
    Validating response structure.
    
28. What is response time assertion?
    Validating API performance.
    
29. What is header assertion?
    Validating HTTP headers.
    
30. What is SoapUI Groovy script?
    Used for custom validations.
    
31. What is data-driven testing in SoapUI?
    Testing with multiple datasets.
    
32. What is property transfer?
    Passing values between requests.
    
33. What is API chaining?
    Using one API’s response in another.
    
34. What is API mocking in SoapUI?
    Simulating API responses.
    
35. What is API security testing?
    Testing auth and access control.
    
36. What is load testing in SoapUI?
    Testing API performance under load.
    
37. What is regression testing?
    Re-testing APIs after changes.
    
38. What is environment testing?
    Testing APIs in different environments.
    
39. What is CI/CD integration?
    Running tests in pipelines.
    
40. What is logging in SoapUI?
    Capturing request/response logs.
    
41. What is backend validation?
    Validating database after API call.
    
42. What is WSDL import?
    Creating SOAP requests from WSDL.
    
43. Difference between SOAP and REST testing in SoapUI?
    SOAP uses WSDL; REST uses endpoints.
    
44. What is endpoint switching?
    Changing environment URLs.
    
45. What is assertion failure?
    When expected result does not match.
    
46. What is API smoke testing?
    Basic API health check.
    
47. What is API contract testing?
    Validating client-server agreement.
    
48. What is fault response in SOAP?
    Error response from SOAP API.
    
49. What is message exchange pattern?
    Request-response communication.
    
50. Why SoapUI over Postman for SOAP?
    Better SOAP and WSDL support.
    

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Real-Time API Validation Example (SoapUI)

Request

<soapenv:Envelope>

  <soapenv:Body>

    <login>

      <username>testuser</username>

      <password>pass123</password>

    </login>

  </soapenv:Body>

</soapenv:Envelope>

Response

<loginResponse>

  <token>abc123</token>

</loginResponse>

Validations

• Status code = 200
  
• Token node exists
  
• Token value not empty
  

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SoapUI Assertions – Interview Examples

XPath Assertion

//token != ”

Response Time Assertion

< 2000 ms

JSONPath Assertion

$.token

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Automation Snippets (SoapUI + Others)

Groovy Script Assertion

assert context.response.contains(“token”)

Postman – Basic Test

pm.response.to.have.status(200);

Rest Assured (Java)

given().get(“/users”).then().statusCode(200);

Python Requests

import requests

assert requests.get(url).status_code == 200

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Scenario-Based API Testing Using SoapUI Interview Questions (15)

1. API returns 200 but wrong data – how do you detect?
   
2. SOAP API returns fault – how do you validate?
   
3. Invalid XML request accepted – defect?
   
4. API slow during peak hours – what test?
   
5. Token expired but API still works – issue?
   
6. Duplicate transaction created – how prevent?
   
7. API works in SoapUI but fails in app – reason?
   
8. Wrong status code returned – impact?
   
9. Partial data saved – how test rollback?
   
10. Schema changed – how detect break?
    
11. API fails only in production – causes?
    
12. Authorization missing – how validate?
    
13. Load test shows memory leak – next step?
    
14. API accepts SQL injection input – severity?
    
15. Backend updated but response unchanged – issue?
    

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How Interviewers Evaluate Your Answers

Interviewers look for:

• Understanding of SOAP and REST
  
• Hands-on SoapUI usage
  
• Clear explanation of assertions
  
• Real-time project examples
  
• Logical, structured thinking
  

👉 Practical explanation > theoretical definitions.

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API Testing Using SoapUI – Quick Revision Cheatsheet

• Know SOAP vs REST clearly
  
• Practice XPath & JSONPath assertions
  
• Validate data, not just status codes
  
• Be ready with real project scenarios
  
• Understand SoapUI features deeply
  

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FAQs – API Testing Using SoapUI Interview Questions

Q1. Is SoapUI still relevant?
Yes, especially for SOAP and enterprise projects.

Q2. Is SoapUI better than Postman?
For SOAP testing, yes.

Q3. Do freshers need SoapUI knowledge?
Basic understanding is enough.

Q4. Biggest mistake candidates make?
Only validating status codes.

Q5. How to prepare quickly?
Practice SOAP & REST APIs with assertions.