QA and SDET Interview Questions India 2026: Test Automation Engineer Guide

QA Engineer: writes and executes test plans and test cases, files bug reports, performs manual exploratory testing, and may write automated tests as one of many responsibilities. Role often found at service IT companies (TCS, Infosys, Wipro) and smaller product companies. Lower salary band. SDET (Software Development Engineer in Test): writes production code as the primary skill. Builds test frameworks, CI/CD test integrations, test infrastructure, and automated test suites. The SDET is an engineer who specialises in quality tooling, not a tester who also codes. Role found at FAANG India and major product companies (Swiggy, Flipkart, Razorpay, PhonePe). Salary comparable to SWE at the same level. The distinction matters: when a Swiggy or Amazon job posting says 'SDET', they want an engineer who writes Java or Python, designs test architecture, and understands distributed systems testing. When it says 'QA Engineer', they may want a mix of manual and automated testing.

Selenium WebDriver (Java or Python): the most commonly tested automation tool. Know WebDriver initialisation and browser factory pattern, element location strategies (ID, name, XPath, CSS selector — prefer ID/name over XPath for stability), explicit waits (WebDriverWait with ExpectedConditions) vs implicit waits (why explicit is preferred: less flakiness), Page Object Model design pattern (separating page structure from test logic), cross-browser testing (Chrome, Firefox, Safari via BrowserStack or Sauce Labs). Cypress (JavaScript/TypeScript): for React and modern web app testing. Know cy.intercept() for mocking API calls, cy.wait() for async operations, component testing mode (Cypress 10+), and why Cypress runs in-browser vs Selenium's remote WebDriver architecture. API testing: RestAssured (Java) or pytest-requests (Python) for automated API tests. Know HTTP method semantics, status code assertions, authentication header handling (Basic, Bearer token, OAuth 2.0), response schema validation (JSON schema), and contract testing with Pact (why contract tests are needed between microservices). Performance testing: JMeter or k6 for load testing. Understand throughput (requests per second), latency percentiles (p50, p95, p99), error rate, and how to read a JMeter summary report.

Test design (not automation) is a core SDET interview component that many candidates under-prepare: 'How would you test the Swiggy checkout flow?' Expected answer: positive path (add item, proceed to checkout, apply coupon, pay via UPI, confirm order), payment failures (payment declined, timeout, network interruption — does the order cancel gracefully?), concurrent orders (two users checking out the same last-in-stock item simultaneously), boundary conditions (minimum order amount, maximum item quantity), and security cases (coupon code tampering, price manipulation in the request). 'Write test cases for a login page.' Positive: valid email and password combination. Negative: wrong password (n+1 attempts should lock), unregistered email, empty fields, SQL injection in the email field (does the app handle it?), XSS in the name field, rate limiting (100 rapid login attempts). Boundary: maximum length email address and password. 'How do you decide between unit tests, integration tests, and e2e tests?' Reference the test pyramid: many unit tests (fast, isolated, test individual functions), fewer integration tests (test service-to-service interactions), even fewer e2e tests (slow, brittle, test user journeys) — and explain why the ratio matters for CI/CD build time.

SDET salary benchmarks: Junior SDET (0-2 years): Rs 8-18 LPA at product companies. Mid-level SDET (2-5 years): Rs 18-45 LPA. Senior SDET (5-8 years): Rs 40-80 LPA. Principal SDET or QA Architect (8+ years): Rs 70-130 LPA. Top SDET employers in India: Amazon (India e-commerce, Alexa, AWS all have large SDET teams), Flipkart, Google, Microsoft Hyderabad (Azure and Office testing infrastructure), Swiggy (test automation culture is strong), and Razorpay (fintech requires high test coverage for payment correctness). At FAANG India, SDETs earn comparable total compensation to SWEs at the same level, including RSUs. Career paths from SDET: move to SWE roles (the automation and systems skills transfer well to backend engineering), move to DevOps or platform engineering (CI/CD infrastructure is natural adjacent), or stay in quality engineering and become a QA Architect (designing testing strategy for an entire engineering organisation).