SDET vs QA Engineer
What Companies Mean by SDET
What Companies Mean by SDET
"SDET" (Software Development Engineer in Test) is a title used by companies including Microsoft, Amazon, Google, and their competitors. But the role varies significantly between organisations. Understanding what it actually means helps you target the right opportunities.
The Original Microsoft Definition
Microsoft coined the term in the 1990s. Their SDETs were engineers who wrote production-quality test code, test infrastructure, and test tools — not just test scripts. They were expected to read and contribute to the production codebase, not just test it.
The bar was high: an SDET who could not code was not an SDET.
What SDET Means Today
The term has diffused. Depending on the company, "SDET" may mean:
Type A — True SDET (Microsoft, Amazon, Google, FAANG-adjacent)
- Designs and builds test frameworks from scratch
- Writes production-quality automation code (not record-and-play)
- Contributes to CI/CD pipeline infrastructure
- Reviews production code for testability
- May write production features in addition to tests
- Interviews assess coding skills at the same bar as software engineers
Type B — Senior Automation Engineer
- Writes automation using existing frameworks (Selenium, Playwright, REST Assured)
- Configures CI pipelines
- Mentors junior testers
- Does not build framework infrastructure from scratch
Type C — Manual + Some Automation
- Primarily manual testing with some scripted automation
- Title "SDET" used loosely
How to Know Which Type You're Applying For
Look at the job description:
- "OOP design patterns", "framework architecture from scratch", "system design" → Type A
- "Selenium", "Playwright", "TestNG/JUnit", "CI integration" → Type B
- "Test cases", "exploratory testing", "some automation experience" → Type C
What This Path Prepares You For
This path targets Type A/B transition — from a manual or automation QA to an engineer who can design frameworks, apply design patterns to test code, and operate comfortably in a software engineering environment.
The skills covered: OOP in Java, SOLID principles, design patterns, framework architecture, CI/CD, and system design basics.
💬 Discussion
Where do you currently sit on the QA-to-SDET spectrum? What is the one skill gap that feels most significant?
A job posting for "SDET" mentions "design patterns," "framework architecture from scratch," and "system design." What type of SDET role is this?
Next Lesson
Skills Gap: Where to Focus