Top 30+ SDET Interview Questions and Answers

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Preparing for an SDET (Software Development Engineer in Test) interview? You will need a strong understanding of automation, testing frameworks, coding, and problem-solving. This guide covers 30+ commonly asked SDET interview questions with answers to help you confidently tackle your interview. 

Let’s get into the most important topics and get you ready for your next SDET role.

Fun Fact: SDET salaries in India typically range from ₹4 Lakhs to ₹29.5 Lakhs for professionals with 1 to 9 years of experience in the field.

Basic SDET Interview Questions

Here is a list of basic software development engineer in test interview questions and answer: 

1. What is the role of an SDET in a development team?

A Software Development Engineer in Test (SDET) integrates into the development team to design, develop, and maintain automated test frameworks. They ensure code quality by writing tests that detect bugs early in the development cycle, contributing to both development and testing efforts.

2. How does an SDET differ from a QA Engineer?

While both focus on product quality, an SDET possesses programming skills to create automated tests and may contribute to code development. In contrast, a QA Engineer primarily conducts manual testing and focuses on identifying defects through exploratory testing methods.

3. What are the key skills required to be an effective SDET?

An effective SDET should have strong programming skills, proficiency in automation tools, a solid understanding of software testing principles, experience with continuous integration/continuous deployment (CI/CD) pipelines, and excellent problem-solving abilities.

4. Can you explain the software testing life cycle?

The software testing life cycle includes phases such as requirement analysis, test planning, test case development, environment setup, test execution, defect tracking, and test closure activities.

SDET Interview Questions for Freshers

Here are some common software development engineer in test interview questions and answers for freshers: 

5. Differentiate between manual testing and automated testing.

Manual testing involves human testers executing test cases without automation tools, suitable for exploratory and usability testing. Automated testing uses scripts and tools to run tests, ideal for repetitive and regression testing tasks.

6. What do you understand about beta testing? What are its different types?

Beta testing is the final testing phase where a product is released to a limited audience outside the company to obtain real-world feedback. Types include open beta, available to the general public, and closed beta, restricted to a specific group of users.

Also Read - Top 75+ Manual Testing Interview Questions and Answers

7. What is alpha testing, and what are its objectives?

Alpha testing is an internal testing phase conducted by developers and testers before beta testing. Its objectives are to identify and fix bugs before releasing the product to external users, ensuring basic functionality and stability. 

8. What is the difference between severity and priority in software testing?

Severity refers to the impact of a defect on the system’s functionality, while priority indicates the urgency of fixing the defect. A high-severity issue affects critical features, whereas a high-priority issue requires immediate attention due to business needs.

SDET Interview Questions for Experienced

Let’s go through important SDET interview questions and answers for experienced candidates:

9. What do you understand about risk-based testing?

Risk-based testing prioritizes testing efforts based on the potential risk of failure and its impact on the business. It focuses on critical functionalities that, if defective, would cause significant issues, ensuring efficient use of testing resources. 

10. Differentiate between white box testing and black box testing.

White box testing involves testing internal structures or workings of an application, requiring knowledge of the code. Black box testing assesses the application’s functionality without internal knowledge, focusing on input-output behaviour. 

11. What is fuzz testing, and what types of bugs does it detect?

Fuzz testing involves inputting random or unexpected data into a system to identify vulnerabilities or crashes. It detects issues like buffer overflows, memory leaks, and input validation errors, enhancing the system’s robustness. 

12. How would you go about creating an automation strategy for a product that doesn’t have any automation tests?

“I would begin by assessing the product’s architecture and identifying critical functionalities. Next, I would select appropriate automation tools, develop a modular and maintainable test framework, prioritize test cases based on risk, and integrate the automation suite into the CI/CD pipeline to facilitate continuous testing.”

Senior SDET Interview Questions

Here are commonly asked senior software development engineer in test interview questions and answers: 

13. How do you design a scalable automation framework?

Designing a scalable automation framework involves:

• Modularity: Breaking down tests into reusable modules.​
• Maintainability: Ensuring code is easy to update and extend.​
• Integration: Aligning with CI/CD pipelines for continuous testing.​
• Parallel Execution: Supporting concurrent test runs to reduce execution time.​
• Robust Reporting: Implementing comprehensive logging and reporting mechanisms.​

14. Explain continuous integration and its importance in testing.

Continuous Integration (CI) is a development practice where code changes are automatically built and tested, facilitating early detection of issues. In testing, CI ensures that automated tests are run frequently, leading to faster identification of defects and more stable software releases.

15. Can you describe your experience with performance testing?

This is one of the most common SDET 2 interview questions.

“In my previous role, I conducted performance testing to assess system responsiveness under various load conditions. Using tools like JMeter, I simulated user traffic, identified bottlenecks, and collaborated with developers to optimize performance, resulting in improved application scalability.”

SDET Technical Interview Questions

These are technical SDET interview questions and answers: 

16. Explain the Page Object Model (POM) in test automation.

The Page Object Model is a design pattern in test automation that creates an object repository for web UI elements. Each web page is represented by a class, and its elements are variables within that class. This approach enhances test maintenance and readability by separating test scripts from the page structure.

17. How do you manage test data for automation?

Managing test data involves:

• Data Generation: Creating synthetic data that mimics real-world scenarios.​
• Data Isolation: Ensuring tests do not interfere with each other’s data.​
• Environment Parity: Maintaining consistent data across different test environments.​ 
• Data Cleanup: Implementing teardown processes to reset data after tests.

SDET Interview Questions Scenario Based

Here are scenario based software development engineer in test interview questions and answers: 

18. Describe a situation where you identified a critical bug during the testing phase.

“While testing a financial application, I discovered a calculation error in interest computations. This bug could have led to significant financial discrepancies. I documented the issue, reported it to the development team, and verified the fix after it was addressed.”

How would you approach testing a new feature with tight deadlines?

“Under tight deadlines, I would:

• Risk Assessment: Identify critical functionalities that must be tested.​
• Prioritization: Focus on high-impact test cases.​
• Automation: Automate repetitive tests to save time.​
• Collaboration: Work closely with developers to understand feature intricacies and potential risk areas.”

SDET Automation Interview Questions

19. What is Selenium, and how have you used it in your projects?

“Selenium is an open-source tool for automating web browsers. In my projects, I’ve used Selenium to automate regression tests, validate UI elements, and perform cross-browser testing, ensuring consistent user experiences across different platforms.”

20. How do you handle dynamic web elements in Selenium?

To manage dynamic web elements:

• Dynamic Locators: Utilize XPath or CSS selectors that adapt to changing attributes.​
• Explicit Waits: Implement waits to handle asynchronous loading.​
• JavaScript Execution: Use JavaScript to interact with elements when traditional methods fail.

Also Read - Top 60+ JavaScript Interview Questions and Answers

SDET Lead Interview Questions

21. How do you prioritize testing tasks in a project?

Prioritization is based on:

• Risk Analysis: Assessing the potential impact of defects.​
• Business Requirements: Aligning with critical business functionalities.​
• Dependencies: Considering task sequences and interdependencies.​
• Resource Availability: Allocating tasks based on team capacity and expertise.​

22. Describe your approach to mentoring junior testers.

“I focus on:

• Knowledge Sharing: Conducting training sessions on testing methodologies.​
• Pair Testing: Collaborating on tasks to provide hands-on experience.​
• Feedback: Offering constructive feedback to promote growth.​
• Encouragement: Motivating junior testers to take ownership of their work and explore new testing approaches.”

SDET Manager Interview Questions

23. How do you align the testing strategy with business objectives?

The testing strategy should directly support business goals by:

• Understanding Requirements: Collaborating with stakeholders to prioritize testing based on business impact.
• Risk-Based Testing: Focusing on areas critical to customer satisfaction and revenue generation.
• Automation Integration: Implementing automation where it maximizes efficiency.
• Continuous Improvement: Adapting test strategies based on product feedback and performance.

24. What metrics do you use to assess the effectiveness of the testing process?

• Defect Density: Number of defects per module or feature.
• Test Coverage: Percentage of code, features, or user scenarios covered by tests.
• Test Execution Time: Time taken to complete test cycles.
• Flaky Test Rate: Percentage of tests that fail intermittently.
• Customer-Reported Defects: Number of defects found after release.

SDET QA Interview Questions

25. What are the differences between quality assurance and quality control in software testing?

• Quality Assurance (QA): Focuses on processes to prevent defects, including test planning, reviews, and standards.
• Quality Control (QC): Focuses on identifying defects in the product through test execution, defect tracking, and verification.

26. How do you make test cases effective?

• Clear Objectives: Each test case should have a well-defined purpose.
• Edge Cases: Cover all possible input variations, including boundary conditions.
• Reusability: Structure test cases so they can be reused in different scenarios.
• Traceability: Link test cases to requirements to verify all functionalities are tested.

SDET Java Interview Questions

27. How do you synchronize a collection in Java?

To synchronize a collection in Java, use Collections.synchronizedList(), Collections.synchronizedSet(), or Collections.synchronizedMap().

Example:

List<String> list = Collections.synchronizedList(new ArrayList<>());

For better concurrency, use CopyOnWriteArrayList, ConcurrentHashMap, or ConcurrentLinkedQueue from java.util.concurrent.

28. Write a Java program to reverse a string.

This is one of the most common Java programs for SDET interview.

public class ReverseString {

    public static void main(String[] args) {

        String original = “Hello, World!”;

        String reversed = new StringBuilder(original).reverse().toString();

        System.out.println(“Reversed string: ” + reversed);

    }

}

Python SDET Interview Questions

29. How do you manage packages and environments in Python?

Use pip to install packages and venv or conda to create isolated environments. venv manages lightweight environments, while conda handles packages and dependencies across multiple projects, supporting different Python versions.

30. Explain the concept of decorators in Python.

Decorators modify function behaviour without changing code. They are used for logging, access control, and caching. 

Example:

def decorator(func):

    def wrapper():

        print(“Before function call”)

        func()

        print(“After function call”)

    return wrapper

@decorator

def say_hello():

    print(“Hello!”)

say_hello()

Also Read - Top 15+ Python Automation Interview Questions and Answers

SDET Coding Interview Questions

Here are some common coding and SDET programming questions:

31. Write a program to find duplicates in an array.

In Java:

import java.util.HashSet;

import java.util.Set;

public class FindDuplicates {

    public static void main(String[] args) {

        int[] array = {1, 2, 3, 4, 5, 2, 6, 1};

        Set<Integer> seen = new HashSet<>();

        Set<Integer> duplicates = new HashSet<>();

        for (int num : array) {

            if (!seen.add(num)) {

                duplicates.add(num);

            }

        }

        System.out.println(“Duplicates: ” + duplicates);

    }

}

32. How would you find the missing number in an integer array?

In Java:

public class MissingNumber {

    public static void main(String[] args) {

        int[] array = {1, 2, 4, 5, 6};

        int n = array.length + 1;

        int expectedSum = n * (n + 1) / 2;

        int actualSum = 0;

        for (int num : array) {

            actualSum += num;

        }

        int missingNumber = expectedSum – actualSum;

        System.out.println(“Missing number: ” + missingNumber);

    }

}

33. How do you check if two strings are anagrams in Java?

You might also come across SDET Java coding interview questions like this one.

Sort both strings and compare them.

import java.util.Arrays;

public class AnagramCheck {

    public static boolean areAnagrams(String str1, String str2) {

        if (str1.length() != str2.length()) return false;

        char[] arr1 = str1.toCharArray();

        char[] arr2 = str2.toCharArray();

        Arrays.sort(arr1);

        Arrays.sort(arr2);

        return Arrays.equals(arr1, arr2);

    }

    public static void main(String[] args) {

        System.out.println(areAnagrams(“listen”, “silent”)); // true

    }

}

Also Read - Top 25+ Interview Questions On String in Java with Answers

Company-Specific SDET Interview Questions

Amazon SDET Interview Questions

1. Write a program to return the mirror tree of a given binary tree.
2. Can you build frameworks from scratch?​
3. What load/performance testing tools are you familiar with?​
4. Do you do both back-end and front-end automation?

Note: The Amazon SDET interview process includes coding tests, technical rounds, system design, behavioural evaluation, and a bar raiser interview.

Meesho SDET Interview

1. Describe your experience with API testing.​
2. How do you ensure the scalability of your test automation?​
3. What strategies do you use for test data management?

Flipkart SDET Interview Questions

1. How do you handle cross-browser testing?​
2. Explain your approach to mobile application testing.​
3. Describe a challenging bug you found and how you resolved it.​

Walmart SDET Interview Questions

1. What are OOPs concepts?
2. How do you integrate test automation into CI/CD pipelines?​
3. Describe your experience with performance testing tools.​
4. How do you ensure the security of your test environments?

Apple SDET Interview Questions

1. What technologies have you used in terms of architecture of open-source test frameworks?
2. What is the difference between Selenium 3 and Selenium 4?
3. Explain your approach to testing user interfaces.​
4. Describe your experience with Swift or Objective-C.

Microsoft SDET Interview Questions

1. How do you design a test strategy for a new feature?​
2. Describe your experience with C# and .NET in test automation.​
3. How do you handle testing for different Windows platforms?

Facebook SDET Interview Questions

1. Explain your approach to testing large-scale distributed systems.​
2. How do you ensure the reliability of your automated tests?​
3. Describe a situation where you improved the performance of a test suite.

Google SDET Interview Questions

1. How do you design tests for complex algorithms?​
2. Describe your experience with Python or Java in test automation.​
3. How do you approach testing for scalability and performance?

Adobe SDET Interview Questions

1. Can you explain how you have used string manipulation in previous projects?
2. Explain your experience with testing multimedia applications.​
3. How do you handle cross-platform testing challenges?​

Oracle SDET Interview Questions

1. How do you test database-driven applications?​
2. Describe your experience with SQL and PL/SQL in testing.​
3. How do you ensure data integrity during testing?

Wipro SDET Interview Questions

1. Which keyword is used in a parent class to override a method?
2. Difference between class variable and instance variable.
3. Can you explain how you handle exceptions in your automation scripts?
4. Describe your experience with various test management tools.​

HCL SDET Interview Questions

1. Explain your approach to testing enterprise applications.​
2. How do you ensure compliance with industry standards in testing?​
3. Describe a challenging testing project and how you managed it.

Cognizant SDET Interview Questions

1. How do you integrate automation testing into a DevOps pipeline?​
2. Describe your experience with behaviour-driven development (BDD).​
3. How do you handle testing for global applications with localization requirements?

Also Read - Top 70+ Automation Testing Interview Questions and Answers

Deloitte SDET Interview Questions

1. How do you approach testing for financial applications?​
2. Describe your experience with risk-based testing methodologies.​
3. How do you ensure the security of sensitive data during testing?

Infosys SDET Interview Questions

1. How do you handle testing for large-scale integration projects?​
2. Describe your experience with service virtualization in testing.​
3. How do you manage test environments for complex systems?

Morgan Stanley SDET Interview Questions

1. How do you test trading applications for performance and reliability?​
2. Describe your experience with automated testing in a financial services context.​
3. How do you ensure compliance with financial regulations during testing?

Cisco SDET Interview Questions

1. Can you sort a list with odd and even numbers together?
2. Can you explain Java collections?
3. How do you approach testing for network protocols and devices?​
4. How do you handle testing for high-availability systems?

IBM SDET Interview Questions

1. How do you test mainframe applications?​
2. Describe your experience with cloud-based testing solutions.​
3. How do you ensure the scalability of your test automation frameworks?

Nutanix SDET Interview Questions

1. Describe a challenging automation project you’ve worked on and how you overcame obstacles.
2. Can you explain object-oriented programming concepts?
3. How do you test hyper-converged infrastructure solutions?​
4. How do you handle testing for software-defined storage systems?

BrowserStack SDET Interview Questions

1. How do you ensure cross-browser compatibility in your tests?​
2. Describe your experience with testing responsive web designs.​
3. How do you handle testing for various mobile devices and platforms?

Akamai SDET Interview Questions

1. What experience do you have with Python coding?
2. Can you explain your familiarity with TCP IP protocols?
3. How do you test content delivery networks (CDNs) for performance?​
4. How do you handle testing for DDoS protection solutions?

VMware SDET Interview Questions

1. How do you test virtualization platforms for stability?​
2. Describe your experience with testing cloud infrastructure services.​
3. How do you ensure compatibility between different virtualized environments?

Freshworks SDET Interview

1. Can you explain a concept related to Selenium?
2. Can you find the longest palindrome in a given string?
3. How do you approach testing for SaaS applications?​
4. Describe your experience with customer relationship management (CRM) testing.​

Salesforce SDET Interview Questions

1. Can you explain some basic Java concepts?
2. Do you have experience with automation?
3. How do you test customizations in Salesforce applications?​
4. Describe your experience with Apex and Visualforce in testing.​

PhonePe SDET Interview Questions

1. How do you test payment gateways for reliability?​
2. Tell me about your knowledge of Selenium API.
3. Describe your experience with mobile application testing for financial services.

MasterCard SDET Interview Questions

1. Explain the difference between Comparator and Comparable.
2. What are the main interfaces in the Java Collections Framework?
3. Explain the different status codes in API testing. ​
4. What is a POJO? Provide an example. ​

Visa SDET Interview Questions

1. What are the differences between unit, functional, and acceptance testing? ​
2. Describe a challenging testing scenario you encountered and how you resolved it. ​
3. How do you ensure the security and reliability of payment processing systems during testing?

Razorpay SDET Interview Questions

1. How do you test payment processing systems for accuracy and security?​
2. Describe your experience with PCI-DSS compliance in testing.​
3. How do you handle testing for high-transaction-volume applications?

Cred SDET Interview Questions

1. How do you ensure the reliability of credit scoring algorithms during testing?​
2. Describe your approach to testing user reward systems.​
3. How do you handle testing for integrations with multiple financial institutions?

Zeta SDET Interview Questions

1. How do you test digital banking platforms for functionality and security?​
2. Describe your experience with API testing in FinTech applications.​
3. How do you ensure compliance with financial regulations during testing?

Swiggy SDET Interview Questions

1. Find if the given two strings are anagrams.
2. How do you approach testing for food delivery logistics systems?​
3. Describe your experience with mobile application testing for consumer services.​
4. How do you handle testing for real-time order tracking features?

Ola SDET Interview Questions

1. How do you test ride-sharing applications for performance and reliability?​
2. Describe your approach to testing GPS and mapping integrations.​
3. How do you ensure the security of user data in transportation apps?

Dunzo SDET Interview Questions

1. How do you handle testing for hyperlocal delivery services?​
2. Describe your experience with testing scheduling and routing algorithms.​
3. How do you ensure the scalability of on-demand delivery platforms?

Agoda SDET Interview Questions

1. How do you test hotel booking systems for accuracy and user experience?​
2. Describe your approach to testing internationalization and localization features.​
3. How do you handle testing for integrations with various payment gateways?

Airtel X Labs SDET Interview Questions

1. What is Enum in Java?
2. How do you approach testing for telecommunications platforms?​
3. Describe your experience with testing large-scale data processing systems.​

Hotstar SDET Interview Questions

1. How do you test streaming services for performance and scalability?​
2. Describe your approach to testing content delivery networks (CDNs).​
3. How do you handle testing for various device compatibilities in media applications?

Cohesity SDET Interview Questions

1. How do you test data management and backup solutions for reliability?​
2. Describe your experience with testing data deduplication features.​

Discovery SDET Interview Questions

1. How do you approach testing for media and entertainment platforms?​
2. Describe your experience with testing user personalization features.​
3. How do you handle testing for high-traffic live streaming events?

Docusign SDET Interview Questions

1. Can you explain how you would capture UI elements using Selenium?
2. How do you test electronic signature platforms for compliance and security?​
3. Describe your approach to testing document workflow automation.​

DP World SDET Interview Questions

1. How do you approach testing for logistics and supply chain management systems?​
2. Describe your experience with testing port and terminal operations software.​

Coupa SDET Interview Questions

1. ​How would you handle a high-priority technical issue for a customer while minimizing operational disruption?​ 
2. ​Describe your process for debugging and resolving a challenging software defect.​ 
3. ​Can you explain the process of configuring the Coupa system to meet specific business requirements?​

Note: Make sure you also practice for Coupa SDET assessment.

SDET Interview Preparation Tips

• Understand automation frameworks and their implementation.
• Practice coding problems related to data structures and algorithms.
• Gain hands-on experience with Selenium, TestNG, and JUnit.
• Review database queries and testing techniques.
• Read about SDET interview experience shared on forums like Naukri and AmbitionBox.

Wrapping Up

And we are done with the top 30+ SDET interview questions that will help you prepare for your next interview. Covering automation, coding, and real-world scenarios, these questions give you a strong foundation. Keep practising and refining your skills. Looking for SDET jobs in India? Visit Hirist, a leading job portal for tech professionals. Find the latest SDET vacancies and IT job opportunities in India.