SDET stands for Software Development Engineer in Test — an engineer who writes code to test software and builds the frameworks, tools, and pipelines that make testing scalable. Unlike a traditional tester who mostly executes manual test cases, an SDET designs automation, reviews code, and works closely with the development team. At most product companies, an SDET is treated as a developer whose product is quality.

The role of an SDET includes designing test automation frameworks, writing automated tests for APIs and UIs, integrating them into CI/CD pipelines, and ensuring new features are testable from the start. It also often covers performance checks, debugging failures, and contributing reusable utilities to the codebase. In short, an SDET makes quality a built-in part of development instead of a final checkpoint.

Automation testing is the practice of using scripts, tools, and frameworks to execute test cases automatically instead of doing it manually. For example, a script can log into an app, complete a payment flow, verify the result, and report failures — on every single build. It is mainly used for repetitive checks like regression, smoke, and API testing where speed and consistency matter.

A test automation framework is a structured set of guidelines, libraries, reusable components, and reporting mechanisms that makes automation scripts easy to write, maintain, and scale. Common patterns include the Page Object Model, data-driven and hybrid frameworks. A good framework is usually what separates a professional automation setup from a pile of loose scripts.

In manual testing, a human executes test steps, observes results, and explores the application — which is great for usability, exploratory, and one-time checks. In automation testing, scripts run the tests repeatedly and quickly, which suits regression suites and CI/CD pipelines. Most teams use both: automation for repetitive coverage and manual testing for judgment-based scenarios.

Yes, automation testing is a good career, especially in India where every product and services company needs engineers who can automate regression and API testing. Pay is typically higher than manual testing roles, and the career path leads to SDET, lead, and architect positions. The key is to build genuine coding skills rather than relying only on record-and-playback tools.

SDET is a good career for people who enjoy coding as much as testing. At product based companies, SDET compensation is often at par with software developers, and the demand for engineers who can code and test keeps growing. The trade-off is that interviews are tougher — you need data structures, coding, and framework design skills, not just tool knowledge.

Indicatively, freshers in automation testing earn around ₹4–6 LPA, mid-level engineers with 4–6 years of experience roughly ₹10–20 LPA, and senior SDETs at large product companies can earn well beyond ₹25 LPA. Actual test automation engineer salary figures vary with your programming depth, framework experience, and the type of company — product companies generally pay more than service companies.

If you already understand manual testing basics and can code a little, around 3–6 months of consistent practice is enough to become job-ready with one language, Selenium, and API automation. Reaching a strong, interview-ready level usually takes 1–2 years of building real frameworks and projects. The timeline depends heavily on how much hands-on practice you do, not just courses you watch.

Start with one programming language (Java or Python), then learn manual testing fundamentals, Selenium WebDriver, and API automation with tools like Rest Assured or Postman. Add Git, TestNG/JUnit, Maven, and a CI tool like Jenkins, and build 2–3 end-to-end projects on practice websites. Learning automation testing this way — one layer at a time with real projects — is what gets you interview-ready.

Start with Selenium WebDriver along with one language (Java is the most demanded in India), then learn TestNG or JUnit, Postman and Rest Assured for API testing, Git for version control, and Jenkins basics for CI. Once these are solid, explore Playwright or Cypress for modern UI automation and Appium if you want mobile testing. Checking live job listings will tell you exactly which stack your target companies want.

Prepare in parallel tracks: daily coding practice (arrays, strings, hashmaps), core Java/Python concepts, Selenium and framework design questions like Page Object Model, API automation, and test scenario questions such as "how would you test this feature." For senior roles, also prepare framework and system design plus behavioral rounds. Solving real SDET interview questions from product companies and doing mock interviews makes a big difference.

Common SDET interview questions include writing code to reverse a string or find duplicates, explaining explicit vs implicit waits, handling dynamic elements in Selenium, designing a framework from scratch, explaining HTTP status codes in API testing, and scenario questions like "test a login page." You will also almost always be asked to walk through your current project's framework in depth.

Expect one or two medium-level coding problems plus practical exercises: string manipulation (palindrome, anagram), array problems like finding the second largest number, hashmap-based questions, and sometimes writing a small utility or automating a given scenario live. Practicing easy and medium problems on platforms like LeetCode and HackerRank, focusing on clean code and edge cases, covers most SDET interview coding questions.

SDET interview questions for product based companies are heavier on data structures and algorithms, framework and system design, and behavioral rounds, because quality engineers there are expected to think like developers. Service based companies focus more on tool proficiency — Selenium, UFT, manual-plus-automation mix — and client project scenarios. If you are targeting product companies, weight your preparation toward daily coding and design discussions.