Top 30 SDET Interview Questions You Need to Know in 2025

Landing a Software Development Engineer in Test (SDET) role can be a game-changer for your tech career. But let’s face it: interviews for SDET positions are tough. They demand a unique blend of coding, automation testing, and problem-solving skills. So, how do you prepare? By mastering the top SDET interview questions for 2025.

And here’s a pro tip: to ace your preparation, check out this free tool from Careerist, packed with IT interview questions tailored for roles like SDET.

Let’s dive into what you need to know to crush that interview.

Common Topics in SDET Interviews

Before we get to the questions, let’s look at what SDET interviews typically cover:

1. Coding Skills – Writing efficient, bug-free code.
2. Automation Frameworks – Experience with tools like Selenium, TestNG, or Cucumber.
3. Testing Techniques – Understanding manual and automated testing.
4. Problem-Solving – Debugging, algorithm challenges, and logical reasoning.
5. Soft Skills – Communication and collaboration within agile teams.

Top 30 SDET Interview Questions for 2025

General Questions

• Can you explain the role of an SDET?
• How does an SDET differ from a QA Engineer?
• What’s your experience with agile development?
• How do you prioritize testing tasks in tight deadlines?
• Have you ever designed a test strategy from scratch?

Coding Challenges

• Write a program to reverse a string.
• How would you find duplicates in an array?
• Explain recursion and provide an example.
• Solve this problem: Find the missing number in an integer array.
• Design a basic calculator in Java/Python.

Automation-Specific Questions

• What is Selenium, and how have you used it?
• How do you handle dynamic web elements in Selenium?
• Explain the Page Object Model (POM).
• Can you compare TestNG and JUnit?
• How would you automate API testing?

Manual Testing & Debugging

• What’s the difference between smoke testing and sanity testing?
• How do you identify the root cause of a bug?
• Can you describe the software development lifecycle?
• What is regression testing, and why is it important?
• How do you test for cross-browser compatibility?

Behavioral Questions

• Tell us about a time you resolved a conflict within your team.
• How do you handle constructive criticism?
• Describe a situation where your testing uncovered a major flaw.
• How do you stay updated on the latest testing trends?
• What motivates you as an SDET?

Advanced Topics

• How do you design a scalable automation framework?
• Explain continuous integration and its importance in testing.
• What are microservices, and how do you test them?
• How do you ensure security in your testing process?
• What tools do you use for performance testing?
  

How to Prepare for SDET Interviews

Mastering these questions is step one. Here’s how to make sure you’re 100% ready:

1. Use Careerist’s Free Tool. The IT Interview Questions tool is perfect for practicing SDET-specific questions. It’s free, easy to use, and designed to help you stand out.
2. Practice Coding. Brush up on languages like Java or Python. Use platforms like LeetCode or HackerRank for algorithm challenges.
3. Learn Automation Frameworks. Deepen your knowledge of tools like Selenium, Postman, and Jenkins.
4. Mock Interviews. Role-play with a friend or mentor. Focus on your technical and soft skills.
5. Stay Updated. Follow blogs, attend webinars, and read up on the latest testing tools and techniques.

Being an SDET is about more than just technical know-how—it’s about problem-solving, adaptability, and continuous learning. Preparing with the top SDET interview questions of 2025 will give you the confidence to tackle any challenge.

And remember, tools like Careerist’s IT Interview Questions tool are there to give you an extra edge. So why wait? Start preparing today and land your dream job as an SDET!