A QA engineer owns the quality of features within an Agile team: refining stories, designing tests, testing UI and APIs, validating data with SQL and supporting automation. Interviews cover test design techniques, API testing with Postman, SQL joins and aggregates, Scrum practices and scenario questions about risky releases or production bugs. Some rounds include a short practical task on an API or database.
API testing SQL validation Agile practices Test design Regression planning
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Send and receive text messages and check order and timestamps. Test sent, delivered and read status. Send emojis, long messages, links and attachments within and over the size limit. Check messages sent while offline are queued and delivered on reconnect. Verify blocking a user stops messages. Test notifications when the app is in background. Check chat history after reinstall or on a second device, and that deleted messages disappear for both users if supported.
02
What is the difference between DELETE and TRUNCATE?
Verify each status change appears in order: placed, accepted, preparing, picked up and delivered. Check the rider's location updates on the map at the expected interval. Test the estimated time updates when there is a delay. Verify notifications for each status. Check behaviour when the network drops and recovers, when the app is reopened, and when the order is cancelled midway. Confirm tracking stops after delivery and the rating screen appears.
Model answer: Situation: a discount was applied twice when users pressed the pay button quickly. Task: I had tested the feature and missed it. Action: I owned it in the retrospective, helped reproduce and verify the fix, and added double-click and slow network cases to our checklist for all payment buttons. Result: similar issues were caught in later sprints, and I learned to always test repeated actions.
12
SQL: verify that soft-deleted users do not appear in the active users list.
-- the active list query used by the app should return 0 rows here
SELECT u.user_id, u.email
FROM users u
WHERE u.is_deleted = 1
AND u.user_id IN (
SELECT user_id FROM active_users_view
);
13
How do specification-based techniques differ from experience-based techniques?
Specification-based (black box) techniques derive tests systematically from requirements: equivalence partitioning, boundary values, decision tables, state transitions and use cases. They give measurable coverage. Experience-based techniques rely on the tester's knowledge and intuition: error guessing, exploratory testing and checklist-based testing. They are good at finding defects the specification never mentioned. Strong testers use specification techniques for coverage and experience techniques to fill the gaps.
Usually yes. Status codes should reflect the result so clients and monitoring can react correctly; an error with 200 can hide failures and break retries. A validation error should return 400 or 422, a missing resource 404 and a server failure 500. Check the API contract first: some legacy APIs document this pattern. If it is not documented, log it as a defect with the request and response attached.
Verify notifications arrive when the app is in foreground, background and closed. Check title, text, icon and that tapping opens the right screen with the correct data. Test with notifications disabled at OS level and inside app settings. Check behaviour after logout, reinstall and on multiple devices with the same account. Test grouping of many notifications, time-sensitive ones, and that no notification shows private data on the lock screen.
List conditions and actions in a table and cover every combination of conditions (rules) — ideal for business rules like loan approval: salary > X AND credit score > Y → approve.
19
Your test repository has many duplicate and outdated test cases. How do you clean it up?
Export the cases and group them by module and requirement. Mark duplicates, merge them into one well-written case, and retire cases for removed features. Check which cases have not been executed or failed in months and confirm whether they are still valid. Link the remaining cases to requirements so gaps are visible. Do it module by module with peer review, and set a rule that every story update also updates its test cases.
20
What is localisation and internationalisation testing?
Internationalisation tests that the product can support many languages and formats; localisation tests that a specific locale is correct for text, currency, date and layout.
Yes, very likely. An index lets the database find rows quickly, like the index of a book. With a small QA table, a full table scan is still fast, but with millions of production rows it becomes slow. Compare indexes on the searched columns in both environments and ask a developer to check the query plan. Test key queries on production-size data in staging, and include data volume in future performance checks.
A development model where each development phase has a matching testing phase, such as requirements with acceptance tests and design with integration tests.
26
How do you chain requests in Postman by passing a token from login to the next call?
// Tests tab of the Login request
const body = pm.response.json();
pm.environment.set('authToken', body.token);
// Next request header:
// Authorization: Bearer {{authToken}}
// Postman replaces {{authToken}} with the saved value
1. Open and close by click and keyboard. 2. Select one, then several options; all show as chips or a count. 3. Deselect an option. 4. Select all and clear all, if available. 5. Search inside the list filters options. 6. Maximum selection limit is enforced with a message. 7. Required field shows an error if none selected. 8. Saved selection persists after refresh. 9. Long option names do not break layout. 10. Screen reader announces selected state.
29
Tell me about a time you worked with developers to make an application easier to automate.
Situation: our UI scripts broke almost every sprint because of generated IDs and CSS class changes. Task: as the QA lead I needed stable tests. Action: I showed developers the failure history, proposed adding data-testid attributes and accessible labels to key components and added a short checklist to the pull request template. Result: within two sprints locator-related failures dropped by most of the previous level and maintenance time fell sharply.
SELECT c.id, c.name, COUNT(o.id) AS order_count
FROM customers c
JOIN orders o ON o.customer_id = c.id
WHERE o.order_date >= CURRENT_DATE - INTERVAL '30' DAY
GROUP BY c.id, c.name
HAVING COUNT(o.id) > 3
ORDER BY order_count DESC;
32
A hotfix build arrives and you have only 15 minutes before deployment. How do you sanity check it?
Read the hotfix ticket to know exactly what changed. First verify the fix with the original reproduction steps and data. Then check the directly connected flows, for example if the fix is in coupon calculation, test applying, removing and paying with a coupon. Finish with a quick smoke of login and the main business flow. Report the result immediately, mentioning what was and was not covered.
33
What are suspension and resumption criteria in a test plan?
Suspension criteria define when testing should be paused because continuing would waste effort, for example when a blocker bug stops the main flow, the build fails smoke testing or the environment is down. Resumption criteria define what must happen to restart, such as a new build that passes smoke testing or the environment restored. Writing these down avoids arguments and shows clearly why testing time was lost.
34
How do you test API error handling for invalid input?
Send requests with missing required fields, wrong data types, values beyond limits, invalid formats such as a bad email, unknown fields and an empty or malformed JSON body. The API should return a 4xx code such as 400 or 422, a clear error message that names the field, and no stack trace or database details. Also check that nothing was partly saved in the database after the failed request.
35
A developer changed a shared header component used on every page. What testing do you plan?
Retest the change itself, then run a focused regression on every page type that uses the header: home, listing, detail, checkout and account. Check navigation links, search, login and logout state, cart count and the mobile menu. Do cross-browser and responsive checks because layout changes affect all sizes. A quick visual comparison against the previous build helps spot alignment issues across many pages.
A test condition is an item or event of the system that can be verified by one or more test cases, derived from the test basis. For example, for a login requirement, conditions include valid login, wrong password, locked account and remember me. Test conditions answer what to test, while test cases describe how to test it with steps, data and expected results. Listing conditions first helps check coverage before writing detailed cases.
39
Tell me about a time you pushed for an accessibility fix the team wanted to postpone.
Situation: before a release, I found the payment form errors were not announced by screen readers and not reachable by keyboard. Task: the team wanted to defer it. Action: I recorded a short NVDA video showing a user could not finish payment, linked it to WCAG and our customer commitments, and proposed a small fix. Result: the fix took half a day, shipped in the release and we added keyboard checks to our definition of done.
40
Describe how you contributed in a sprint retrospective to improve quality.
Model answer: Situation: our sprints kept ending with stories stuck in testing. Task: suggest a fix in the retrospective. Action: I showed that most stories reached QA in the last two days and proposed smaller stories, early test case sharing and developers deploying to QA daily. Result: the team tried it next sprint, and the number of stories carried over dropped from five to one.
Frequently asked questions
What does a QA Engineer do?
A QA engineer owns the quality of features within an Agile team: refining stories, designing tests, testing UI and APIs, validating data with SQL and supporting automation. Interviews cover test design techniques, API testing with Postman, SQL joins and aggregates, Scrum practices and scenario questions about risky releases or production bugs. Some rounds include a short practical task on an API or database.
Which skills are tested in a QA Engineer interview?
Expect questions on API testing, SQL validation, Agile practices, Test design, Regression planning. Most rounds also ask you to explain a project and solve one practical problem live.
How do I prepare for a QA Engineer interview?
Revise Agile, SQL and API Testing, Test Case Design, Testing Types first using the topic sheets, practise the questions on this page aloud, then do one full mock interview to practise timing.