Engineering
Senior Full Stack Engineer Practice Test
20 multiple choice questions for senior full stack engineers: JavaScript, React, SQL, Next.js, TypeScript, API design and security.
- Questions
- 20
- Time
- 20 min
- Pass mark
- 60%
No account or email needed.
About this test
This test is built around the Senior Full Stack Engineer (Next.js and Node.js) role. It covers the whole stack: JavaScript and React on the front, Next.js server features, TypeScript, SQL and data safety, API design and common security problems.
It is practice only and is not part of any job application.
What it covers
The question set has 25 questions: 13 easy, 10 medium and 2 hard. Each attempt draws 20 of them at random, so a second try is not the same test.
- API design and data (4)
- JavaScript (5)
- Next.js (3)
- React (5)
- Security (2)
- SQL (4)
- TypeScript (2)
Try a few sample questions
These are real questions from the set, with the answers and a short explanation. Read the question, decide, then open it to check.
Sample 1 · JavaScript · easyWhat does typeof null return in JavaScript?Show the answer
- "null"
- "object"Correct
- "undefined"
- "number"
This is a long-standing quirk of the language. typeof null is "object", so check for null with value === null instead.
Sample 2 · React · easyWhat does JSX turn into when your code is built?Show the answer
- HTML strings
- Function calls that create React elementsCorrect
- CSS rules
- Web components
JSX is syntax for creating elements. A compiler turns it into function calls such as React.createElement or the jsx runtime.
Sample 3 · SQL · easyWhich clause filters individual rows before they are grouped?Show the answer
- HAVING
- WHERECorrect
- GROUP BY
- ORDER BY
WHERE filters rows before grouping. HAVING filters the groups afterwards.
How it works
- 20 multiple choice questions, drawn at random from a larger set.
- 20 minutes on the clock. The test submits itself when time runs out.
- Pass mark: 60%.
- No marks are taken off for wrong answers, so answer every question.
- Some questions have more than one correct answer. You must pick all of them to score.
- When you finish you see your score, the correct answers and a short explanation for each.
- Your answers save as you go, so a dropped connection will not lose your work.
- Please stay on the test page. Switching to another tab or window is recorded and you will see a warning.
- Copying text, printing and screenshots are not allowed during the test.
This role is open
This test is built around the Senior Full Stack Engineer (Next.js and Node.js) role on our jobs board. Taking it is not part of the application.
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