Complete SDET Interview Guide
Automation testing and SDET interviews follow a predictable shape: explain your framework, answer technical questions on Selenium, Java, API testing and SQL, write a small program, and handle scenario and behavioural questions. This guide explains each round, what interviewers are really checking, how to structure your answers, and exactly which tutorials to revise — plus a two-week preparation plan.
The Typical Interview Process
| Round | What happens | What they're checking |
|---|---|---|
| 1. Screening | Recruiter or short online test | Experience, tech stack, notice period, basics |
| 2. Technical — tools & framework | Selenium/Playwright, API, TestNG, your framework | Real hands-on depth, not definitions |
| 3. Technical — coding | 1–3 Java programs, sometimes SQL | Logic, clean code, edge cases |
| 4. Managerial / scenario | Project, process and "what would you do if…" | Judgement, ownership, communication |
| 5. HR | Motivation, expectations, fit | Clarity and professionalism |
Service companies often combine rounds 2 and 3; product companies usually add more coding. Company-specific patterns are in Part 2 below.
The Round That Decides Most Interviews: Your Framework
For experienced candidates, "Explain your automation framework" is usually the most important question. A strong two-minute answer follows this order:
- Type and stack — "A hybrid framework with Selenium, Java, TestNG and Maven, following the Page Object Model."
- Structure — base classes, page objects, tests, utilities, test data, configuration.
- Execution — testng.xml, groups, parallel runs, environments.
- Reporting — Extent/Allure, screenshots on failure, logs.
- CI/CD — Git, Jenkins, when it runs, how results reach the team.
- One real challenge you solved — flaky tests, dynamic elements, test data.
Full walkthrough with a ready spoken answer: How to Explain Your Automation Framework (7 Layers).
Part 1 — Framework & Project Explanation
- How to Explain Your Automation Framework — the 7-layer architecture and a ready answer.
- OOP Concepts in Your Framework — encapsulation, inheritance, polymorphism and abstraction mapped to real framework code.
- Java Collections in Your Framework — List, Set and Map with real examples.
- Explaining an E-Commerce or Banking Project
- Explaining a Healthcare or Insurance Project
- Real-Time Questions: Framework, Testing & Automation
- Real-Time Questions: Process, Team & Environment
- Build an E-Commerce Framework Step by Step — if you need a framework to talk about
Technical Rounds: What to Revise
| Topic | Question bank | Full guide |
|---|---|---|
| Selenium | Top 50 Selenium Questions | Selenium Guide |
| Java | Java Questions for Testers | Java for Testers |
| API testing | Top 30 API Questions | API Testing Tutorial |
| REST Assured | Top 25 REST Assured Questions | REST Assured Tutorial |
| TestNG | TestNG Questions | TestNG Cheat Sheet |
| SQL | Top 25 SQL Questions | SQL for Testers |
| Playwright | Top 20 Playwright Questions | Playwright Tutorial |
| BDD / Cucumber | Top 15 BDD Questions | Cucumber BDD Tutorial |
| Jenkins / CI | Top 20 Jenkins Questions | Jenkins Tutorial |
| Git | Top 20 Git Questions | Git Tutorial |
| Jira | Top 20 Jira Questions | Jira for Testers |
| Manual testing | Top 30 Manual Testing Questions | Manual Testing Tutorial |
The Coding Round
Expect array, string and number programs — reverse a string, find duplicates, second largest, pair with a given sum, anagram, prime and palindrome. Interviewers score your reasoning and edge-case handling as much as the final code.
- Java Coding Programs for Interview — the 6 patterns behind most questions.
- Top 30 SDET Coding Questions — with tested solutions.
- Java Coding Programs Cheat Sheet — for last-minute revision.
How to answer: repeat the problem and ask one clarifying question, state the simple approach and its complexity, improve it, write clean code, walk through an example and the edge cases, then say how you'd test it.
Part 2 — Company Interview Experiences
- ValueLabs · Wipro · Coforge · Cognizant & Infosys
- Company Question Checklists — LTIMindtree, TCS, Deloitte, DEC and a 240-question bank
- Company-Wise Interview Questions and Company Coding Problems
Part 3 — Scenario & Behavioural Questions
These test judgement: what you would do. Answer with the STAR structure — Situation, Task, Action, Result — and always include the result.
- Top 25 Scenario-Based Testing Questions
- Requirement & Execution Scenarios · Requirement Changes & Release Pressure
- When a Developer Rejects Your Bug · Defect Management & Communication
- Testing Under Constraints · Automation Decisions & Flaky Tests
- Production Incidents & RCA · Tricky Situations
- How Would You Test a Pencil? — the classic test-design question
- Behavioral Interview Guide and HR Interview Guide
Prepare by Experience Level
| Experience | Focus |
|---|---|
| 0–2 years | Testing fundamentals, Java basics, Selenium commands, locators, waits, simple coding programs |
| 3–5 years | Framework design and explanation, API automation, CI/CD, flaky-test handling, scenario questions — see SDET Prep for 3–5 Years |
| 5+ years | Test strategy, architecture decisions, parallel execution at scale, mentoring, quality metrics, stakeholder communication |
A Two-Week Preparation Plan
| Days | Focus |
|---|---|
| 1–2 | Write and rehearse your framework and project explanation out loud |
| 3–4 | Selenium and TestNG questions; write the common snippets from memory |
| 5–6 | Core Java concepts and collections |
| 7–8 | Coding: two patterns per day, timed |
| 9–10 | API testing and REST Assured; SQL queries |
| 11–12 | Scenario questions with STAR stories; Jenkins, Git and Jira |
| 13 | Two full mock interviews |
| 14 | The night-before revision plan — then rest |
Practise out loud with the Mock Interview Practice tool and the interview simulators for Selenium, Java and API testing.
Common Mistakes
- Reciting definitions instead of explaining how you used something in your project.
- Claiming experience you can't explain — interviewers ask follow-up questions.
- Silent coding — think out loud, even when you're unsure.
- Blaming developers or teammates in scenario answers.
- No questions for the interviewer — ask about the team's framework, release process and biggest quality challenge.
From Real Projects
Across Apkope, Canolog and Testsigma I've done both manual testing and Selenium automation in Java with TestNG, tracked execution in TestRail and defects in Jira, and worked in Agile teams. The topics on this page connect directly to that day-to-day work. Prepare your project explanation first; almost every other question leads back to it.
Frequently Asked Questions
How do I explain my automation framework in an interview?
Introduce the framework type and stack, then walk through its structure (base classes, page objects, tests, utilities, data, configuration), how it executes, how it reports, how it runs in CI, and one real challenge you solved.
What coding questions are asked in automation testing interviews?
Mostly array, string and number programs — reversing, duplicates, second largest, pair sum, prime, palindrome and anagram — solved in Core Java with attention to edge cases.
How do I prepare for a specific company?
Use the company experiences and checklists in Part 2 to see their round structure and question patterns, then revise the matching technical topics.
What are scenario-based questions?
Questions about how you'd handle real situations — flaky tests, production issues, requirement changes, disagreements. Answer with STAR: situation, task, action and result.
Which topics should I revise before an automation interview?
Your framework and project first, then Selenium, Core Java, API testing and REST Assured, SQL, TestNG, and Jenkins/Git basics — using the question banks in the table above.
How long should I prepare?
If you already work in automation, about two focused weeks. If you're moving from manual testing, follow a longer path such as Manual Tester to Automation or 0 to SDET in 6 Months.
