SDET interviews usually run in stages: a recruiter screen, a technical phone screen, a longer technical round with live coding and framework design, then a behavioural round. Most candidates are filtered out at the phone screen, so the basics below matter most.
This is a short version of my full guide, which has more questions and fuller answers: SDET Interview Questions 2026.
What the questions cover
- Programming and coding: which language you use and why, object-oriented basics, a small coding task such as reversing a string without the built-in method, list vs tuple in Python.
- Selenium and web automation: implicit vs explicit waits, handling dynamic elements, the Page Object Model, file uploads.
- API testing: GET vs POST, how to validate a response in an automated test, authentication vs authorization.
- Framework design: how you would build a framework from scratch, and how you decide what to automate and what to leave manual.
- CI/CD: what CI/CD is and where tests fit into it.
Two examples
Implicit vs explicit wait. An implicit wait sets one global timeout for every element lookup. An explicit wait waits for a specific condition (for example, an element being clickable) on a specific element. Explicit waits are more precise and are usually the safer default; avoid mixing the two, because the timeouts can interact in confusing ways.
What do you automate? Tests that run often, have stable requirements, take long to run by hand, or are easy to get wrong manually. Leave one-off checks, exploratory testing and fast-changing screens alone, because the maintenance cost outweighs the benefit.
A tip on answers
Say what you actually did, in your own words. Interviewers can tell a rehearsed script from real experience, so use the answers above as a structure, not something to recite.
Full question list with complete answers: https://aitestingguide.com/sdet-interview-questions/
