40 SDET interview questions (with example answers)

Updated 4 June 2023

A software development engineer in test (SDET) works with software development and testing. Interview questions for an SDET role often cover core concepts and technical situations regarding various development and automation testing processes. If you're preparing to interview for an SDET position, studying questions you may expect and developing your answers can help you impress hiring managers. In this article, we list 40 SDET interview questions, explain why interviewers ask them and share example answers to some of those questions to use as inspiration.

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14 general SDET interview questions

When your interview begins, the hiring manager is likely to ask some general SDET interview questions. These simple and quick questions help you adjust to the interview setting. During this part of the meeting, interviewers analyse your answers to learn more about your personality and approach to working in software testing. Here are examples of general questions they might ask:

Why are you leaving your current job?
Why do you want to work for this company?
Why have you decided to work as an SDET?
Summarise your CV.
If you could change one thing about your personality, what would you change, and why?
What three words would your former colleagues use to describe you?
Where do you see yourself in 10 years?
Why are you an ideal candidate?
What is your greatest weakness in the workplace?
What aspect of working in software testing do you find the most interesting?
What do you plan to accomplish in the first three months of working here?
What do you do in your spare time?
What skills are essential for software testing specialists?
How do you stay up to date with software testing trends and news?

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10 questions about background and experience

During the second part of your interview, a hiring manager may ask about your background, education and work history. Your answers allow them to learn more about the projects you've completed or how you developed solutions to challenges you encountered whilst testing software. Here are some questions about background and experience that you may hear during an SDET interview:

How has your education or training prepared you for this role?
How long have you worked in software testing?
List your key responsibilities in your previous role.
What is the biggest software testing challenge you've encountered?
What is your biggest professional accomplishment to date?
When was the last time you used fuzz testing?
What have you done in the last six months to improve your programming skills?
What key test-case categories have you used in your previous role?
Do you have experience using project management methodologies in software testing environments?
What methods or tools have you used to prioritise tasks and organise multiple project deadlines?

12 in-depth SDET questions

After learning about your background, interviewers may want to obtain information about your SDET expertise and knowledge. To do that, they're likely to ask in-depth questions about core concepts that software development engineers in test work with, such as automated testing cycles or operational defects. Here are examples of in-depth questions for an SDET role:

What is ad-hoc testing?
How do you create a good bug report?
What methods do you use to group test cases?
Is the understanding of A/B testing essential for an SDET? Describe how they may use it.
What is code inspection, and how do you approach this process?
What processes help you test for operational defects?
Which tasks do you prioritise when testing security authorisations?
What is risk-based testing?
How do you test the text box without background functionality?
Define beta testing and list its different types.
Create a program to swap two numbers without using the third variable.
Write a program that allows you to reverse a number.

4 SDET questions with sample answers

Studying sample answers is an effective way to learn what hiring managers expect to hear during a job interview. In most instances, your answers help them identify and define key qualities that you might use to complete tasks and work as a part of a larger software testing team. Reviewing example answers also helps you decide how to structure your interview answers. Here are some examples to use as inspiration:

1. What is the difference between an SDET and a manual tester?

This general question tests your understanding of the profession. Hiring managers may also ask it to determine if you're familiar with the job specifications that they listed in the job description. To answer the question, discuss example responsibilities in both roles. Then, explain some key differences between the two roles. For example, state at what stage of the development process each specialist does the testing.

Example: 'Both roles aim to identify flaws in software. The main difference between them is that an SDET participates in the development process, and the tester examines specific features of the software once the development process closes. For this reason, it's more common for SDETs to use their testing knowledge and design and development expertise. It's also a requirement to have strong programming knowledge and skills. Employers require different skills from testers because this role concentrates on manually testing the software and its features rather than considering the software's performance elements.'

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

This question tests your practical testing expertise. To answer the question, define each concept briefly. Also, give examples of how severity and priority reflect an SDET's day-to-day work.

Example: 'Priority is the order in which someone repairs faults. For example, labelling something as a high priority means that the fault requires urgent attention. From my experience, defects that affect the entire software have higher priority than those that impact its smaller elements. Severity refers to a defect's ability to impact the software. For instance, flaws which have high severity are more likely to impact the entire software's functionality negatively, whereas those with a lower level of severity may only disable specific functions, allowing the software to continue running even with those defects.'

3. What is your process for creating test plans?

Asking this question allows hiring managers to learn about your approach to planning, documenting and communicating project requirements to complete software testing procedures. To provide an effective answer, list the steps you take when gathering specifications. Then, explain your approach towards creating reports and finalising automation test plans to demonstrate your practical skills as an SDET.

Example: 'Test plans usually detail the project scope, resources, budget, methods and schedules for completing each test cycle. They can depend on what type of test case the team is addressing. For instance, at my previous job, I was responsible for documenting and communicating the plans for initiating new database test cases. In each report, I detailed the tasks for each test cycle, designated team roles and responsibilities and explained an analysis of the associated risks of cross-browser data transfer.

Planning the scope of each test case in this way helped me make sure my team members were up to date with the approved project specifications. It also showed me that they understood their roles at each stage. This approach helped the team coordinate its efforts more effectively and complete the project ahead of schedule.'

4. A tester decides that a product is ready for use in a live environment, but you disagree. What do you do?

This is a situational question that tests your logical thinking, decision making and communication skills. When asking this question, interviewers want to know that you can politely disagree with someone and discuss the priorities of the project you're working on. In your answer, explain how you might react and briefly describe the process of deciding if a product is ready for the live environment.

Example: 'If I disagree with someone's decision, I approach them to ask directly about their judgement and the thought process they used. Approving a product for live environment usage is a critical element of each project, so a team of experts usually makes this decision. My priority is to make sure they've not made the decision independently. In addition, I ask about their validation process. For example, I might analyse the bug reports and test cases.'