SDET and QA Automation Interview Prep
One plan for QA automation and SDET interviews in Java. Work through the stages from top to bottom, or open any stage. Every question is answered and checked on its page.
Every article and the first 2 questions of each topic are free. Pro+ opens the rest and the mock interview.
1Your languageThe Java or Python fundamentals interviewers check first. · 13 topics0/126
- Not startedBasics: types, variables and operators0/11
- Not startedConditions and loops0/8
- Not startedStrings0/9
- Not startedCollections: lists, sets and maps0/13
- Not startedMethods and functions0/9
- Not startedClasses and objects (OOP)0/17
- Not startedKeywords, access and scope0/8
- Not startedExceptions0/10
- Not startedLambdas, streams and comprehensions0/10
- Not startedFiles and input/output0/8
- Not startedMemory and the runtime0/8
- Not startedThreads and concurrency basics0/8
- Not startedDesign patterns in test code0/7
- Open the Your language stage
2Predict the outputRead short code and type exactly what it prints. · 8 topics0/79
- Not startedStrings and immutability0/10
- Not startedNumbers and arithmetic0/10
- Not startedOperators, conditions and loops0/10
- Not startedReferences, copies and mutability0/9
- Not startedCollections0/11
- Not startedExceptions and finally0/10
- Not startedClasses, static members and inheritance0/10
- Not startedScope, closures and lambdas0/9
- Open the Predict the output stage
3Coding problemsA curated problem sheet by topic, solved in Java or Python and checked by hidden tests. · 12 topics0/112
- Not startedBasics and maths0/12
- Not startedArrays0/11
- Not startedStrings0/17
- Not startedHashing: counting and lookups0/13
- Not startedSorting0/6
- Not startedBinary search0/6
- Not startedTwo pointers and sliding window0/7
- Not startedRecursion and backtracking0/7
- Not startedLinked list0/9
- Not startedStack and queue0/6
- Not startedTrees0/10
- Not startedFurther problems0/8
- Open the Coding problems stage
4Testing fundamentalsTesting terms, test design, defects and process, then real scenarios. · 10 topics0/102
- Not startedWhat testing is: terms and principles0/10
- Not startedTest levels and test types0/11
- Not startedTest design techniques0/11
- Not startedWriting test cases and scenarios0/9
- Not startedDefects and bug reports0/11
- Not startedSDLC, STLC and Agile0/10
- Not startedTest planning, estimation and metrics0/12
- Not startedRisk, strategy and when to stop0/10
- Not startedPerformance, security and other non-functional testing0/9
- Not startedScenario practice0/9
- Open the Testing fundamentals stage
5Automation tool (Selenium)Selenium WebDriver from the first browser to advanced tasks, run on the page. · 10 topics0/152
- Not startedSelenium basics and browser control0/13
- Not startedLocators and XPath0/21
- Not startedWaits0/15
- Not startedClicks, typing and reading elements0/19
- Not startedMouse, keyboard and JavaScript0/16
- Not startedAlerts, frames and windows0/17
- Not startedDropdowns and tables0/17
- Not startedScreenshots, uploads and downloads0/11
- Not startedSelenium exceptions and debugging0/12
- Not startedGrid, headless runs and tool choice0/11
- Open the Automation tool (Selenium) stage
6API testingFrom HTTP basics to automated API checks. · 8 topics0/113
- Not startedHow HTTP and the web work0/13
- Not startedHTTP methods and requests0/11
- Not startedStatus codes0/15
- Not startedAuthentication and authorization0/12
- Not startedDesigning API tests0/18
- Not startedPostman and manual API testing0/13
- Not startedAPI automation0/20
- Not startedContracts, mocks and API styles0/11
- Open the API testing stage
7FrameworkTest runner, page objects, data, reports, parallel runs and explaining your framework. · 9 topics0/83
- Not startedTest runner basics (TestNG or pytest)0/12
- Not startedGroups, fixtures, listeners and retries0/11
- Not startedPage objects and design patterns0/9
- Not startedTest data and configuration0/8
- Not startedReporting, screenshots and logs0/7
- Not startedParallel and CI runs0/8
- Not startedBDD with Cucumber or behave0/9
- Not startedFlaky tests and failure triage0/8
- Not startedExplain your framework0/11
- Open the Framework stage
8SQLQueries testers write, from SELECT to joins and data checks, run on a real database. · 12 topics0/104
- Not startedSELECT basics0/7
- Not startedFiltering and sorting0/10
- Not startedWorking with NULL0/8
- Not startedAggregate functions0/8
- Not startedGROUP BY and HAVING0/8
- Not startedJoins0/9
- Not startedSubqueries0/7
- Not startedNth highest and ranking0/9
- Not startedUNION and set operations0/7
- Not startedCreating and changing data (DDL and DML)0/9
- Not startedKeys, constraints, indexes and transactions0/11
- Not startedData checks a tester writes0/11
- Open the SQL stage
9CI/CD and toolsGit, build tools, Jenkins, GitHub Actions and Docker for running tests. · 9 topics0/91
- Not startedGit basics0/10
- Not startedBranching and merging0/11
- Not startedBuild tools and running tests from the command line0/11
- Not startedJenkins0/11
- Not startedGitHub Actions0/11
- Not startedDocker0/9
- Not startedParallel and scheduled runs0/7
- Not startedReading a failed pipeline0/10
- Not startedJira, Linux and other everyday tools0/11
- Open the CI/CD and tools stage
10Project and behaviouralIntroduce yourself, walk through your project and answer HR questions well. · 5 topics0/40
- Mock interviewA timed mix of questions from every stage, with a scorecard at the end.Pro+
Guide
SDET and QA automation interview preparation
A guide to SDET and QA automation interviews: what each round checks, the order to prepare in, and how this plan covers it.
How SDET and QA automation interviews work
Most SDET and QA automation interviews follow the same pattern, though the number of rounds and their order change from company to company. A recruiter or online screen comes first. Then one or two technical rounds test your language and coding, and another tests how you think about testing. Many companies add a round on automation and framework design, and a final round on your projects and behaviour with the hiring manager.
Service companies often start with an online test of aptitude, language basics and output questions. Product companies usually spend more of the day on coding problems and on designing tests and frameworks. Either way the interviewer is checking the same thing: can you write working code, can you find what is likely to break, and can you build automation that a team can trust.
- Language and coding: core Java or Python, reading code, and easy to medium coding problems.
- Testing knowledge: test design, defects, the test process, and scenario questions such as "how would you test a login page?"
- Automation: Selenium WebDriver, waits, locators and the problems that make tests flaky.
- API, SQL and tools: HTTP and REST checks, queries to verify data, Git and running tests in CI.
- Framework and project: how your framework is built, and why you made the choices you did.
- Behaviour: introducing yourself, walking through a project, and answering HR questions.
An 11-stage plan, in the order interviews test it
The plan above puts every topic an SDET or QA automation interview covers into one list, starting with the basics. Each stage opens to its topics, and each topic has a short article followed by questions from easy to hard.
- 01Your language. Java or Python fundamentals: types, strings, collections, OOP, exceptions and more.
- 02Predict the output. Read a short program and type exactly what it prints, as written tests ask.
- 03Coding problems. A curated problem sheet by topic, solved in Java or Python and checked by hidden tests.
- 04Testing fundamentals. Testing terms, test design techniques, defects, process and real test scenarios.
- 05Automation tool (Selenium). Selenium WebDriver tasks, run in a real browser from the page.
- 06API testing. HTTP and REST basics up to automated API checks.
- 07Framework. TestNG or pytest, page objects, test data, reports, parallel runs and explaining your framework.
- 08SQL. The queries testers write, run against a real database in the browser.
- 09CI/CD and tools. Git, build tools such as Maven, Jenkins, GitHub Actions and Docker for running tests.
- 10Project and behavioural. Introduce yourself, explain your project and answer HR questions.
- 11Mock interview. A timed 30-minute round with one question from each stage and a scorecard at the end.
Java or Python for an SDET interview?
Use the language you will write automation in. Java with Selenium and TestNG is still the most common stack in job posts for automation testers, and Python with pytest is common in newer teams and for API and data work. Interviewers rarely mind which one you pick for a coding problem, as long as you know it well.
Every stage here works in both. Switch between Java and Python at the top of the page and the articles, starter code and answers follow; the coding problems are written so the same statement fits either language.
How much DSA and coding does an SDET interview need?
Less than a software developer interview, but more than many testers expect. The coding round usually asks easy to medium problems on strings, arrays, hash maps, stacks and queues, and at some product companies linked lists or trees. A clean, working solution that handles empty input and edge cases matters more than a clever one.
The coding stage is a curated sheet of about 110 problems grouped by topic. Each one runs against hidden tests, including large inputs, so a solution that is right but too slow fails the way it would in an online assessment. The output stage trains the other half: reading code and saying what it prints.
How to prepare for an SDET interview, and for how long
With a working knowledge of one language and some automation, four to eight weeks of steady practice is a realistic window for most people; a few weeks is enough if you are refreshing for an interview you already have. Go stage by stage rather than jumping to the hard topics first.
- Fix your language basics and output questions first; they decide many online tests.
- Solve a few coding problems every day, starting with strings and arrays.
- Practise saying test scenarios out loud: positive, negative, boundary and non-functional cases.
- Run real Selenium, API and SQL tasks instead of only reading answers.
- Prepare a two-minute walkthrough of your framework and your current project.
- Take the mock interview, then go back to the stages the scorecard marks weakest.
Freshers and experienced testers
Freshers are tested mostly on language basics, output questions, coding problems, testing fundamentals and SQL. With two to five years of experience, interviewers expect Selenium and API automation from real work, and ask how you handled flaky tests, test data and CI. Beyond that, framework design, test strategy and leading other testers carry more weight. The stages run from basics to advanced, so start where your gaps are.
What the "Asked in" tags mean
Many questions show the companies where a similar question has been reported, from public interview experiences and company question lists, such as TCS, Infosys, Accenture, Capgemini, Wipro, Cognizant, Amazon, Microsoft and Google. A tag means the question has come up there before. It is not a promise that it will be asked again, and companies change their rounds often.
What is free, and what Pro+ opens
Every article and the first two questions of every topic are free, in both languages, with no card needed. Pro+ opens the rest of the 1,300-plus questions and the timed mock interview, and includes everything in CodeKru Pro. It is a one-time payment for 30 or 365 days, and nothing renews.
Questions people ask
How many rounds are there in an SDET interview?
Usually three to six. A common pattern is an online test or recruiter screen, one or two technical rounds on language and coding, a round on testing and test design, sometimes a round on automation and framework design, and a final round with the hiring manager or HR. The exact rounds differ by company and change over time.
What does the coding round in an SDET interview test?
Mostly easy to medium problems on strings, arrays, hash maps, stacks and queues, written in the language you choose, and sometimes linked lists or trees at product companies. Interviewers look for a working solution, sensible edge cases and the ability to test your own code. Some rounds also ask you to predict the output of a short program.
How long does it take to prepare for an SDET interview?
For most people with one language and some automation experience, four to eight weeks of regular practice is enough. Refreshing for an interview you already have can take two or three weeks. Work through the stages in order, then use the mock interview to find what to revise.
Should I prepare for an SDET interview in Java or Python?
Prepare in the language you use, or want to use, for automation. Java with Selenium and TestNG is the most common combination in automation testing jobs, and Python with pytest is common for API and newer UI automation. Every stage of this plan is available in both.
How much DSA do I need for an SDET interview?
Enough to solve easy and medium problems confidently: strings, arrays, hash maps, sets, stacks, queues, sorting and two pointers, plus basic linked lists and trees for product companies. Advanced topics such as dynamic programming are asked far less often for SDET roles than for developer roles.
Is SQL asked in QA automation interviews?
Often, yes. Testers are asked to write queries to check data: filtering, sorting, joins, GROUP BY with HAVING, and finding duplicates or the second highest salary. The SQL stage here runs every query on a real database in the browser, so you see the result instead of guessing.
Should I learn Selenium or Playwright for interviews?
Look at the jobs you are applying for. Selenium WebDriver is still asked in most automation tester interviews, especially with Java, and its concepts of locators, waits and page objects carry over to Playwright. This plan practises Selenium in a real browser; CodeKru also has a separate Playwright course if your target jobs ask for it.
How is an SDET interview different from a QA automation engineer interview?
The topics overlap a lot. SDET interviews usually put more weight on coding problems and on designing frameworks and tools, while QA automation interviews spend more time on testing knowledge, Selenium, API testing and test scenarios. Preparing all the stages covers both.
What is asked in the framework design round?
You explain how your automation framework is built: the test runner (TestNG or pytest), page objects, where test data and configuration live, how reports and logs work, how tests run in parallel and in CI, and how you keep tests from being flaky. The framework stage has questions and articles on each of these.
Is Interview Prep free?
Every article and the first two questions of each topic are free in Java and Python. Pro+ opens all other questions and the timed mock interview, with a one-time payment for 30 or 365 days that does not renew.