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Frontend Engineer interview questions

Frontend interviews test whether you care about the person on the other side of the screen as much as about the code. Expect questions on performance, accessibility and working with designers, asked through things you actually shipped.

Questions to expect

  1. Tell me about a page or screen you made noticeably faster.

    What they listen for

    That you measured before guessing: which metric, on which device, what the number was before and after. One cause found and fixed beats a list of techniques.

  2. How do you make sure what you build is accessible?

    What they listen for

    Habits, not slogans: keyboard, screen reader, contrast, and when in the work you check them. A bug you caught that way makes the answer credible.

  3. Describe a time a design could not be built as drawn. What did you do?

    What they listen for

    That you went to the designer with options and their cost, early, rather than shipping something different in silence.

  4. How do you decide where state should live in an application?

    What they listen for

    A simple rule you can explain to a junior, and an example where the wrong choice hurt you.

  5. Tell me about a bug that only happened for some users.

    What they listen for

    A method: how you reproduced it, what you ruled out, how you confirmed the fix on the real device or browser.

One answer, before and after

Tell me about a page or screen you made noticeably faster.

You said

I did a lot of performance work on our dashboard. I used lazy loading and memoization and code splitting, and I optimised the images too, and it got a lot faster, users were happier.

Try

Our dashboard took 6 seconds to become usable on a mid-range Android phone. I profiled it and found one chart library was 40 % of the bundle. I loaded it only when the chart scrolled into view, which brought the page to 2.4 seconds. Support tickets about 'the slow dashboard' stopped within the month.

One cause, one fix, and the number before and after, on a device that matters.

What a report scores for this role

User focus
Your answers start from what the person saw, not from the framework.
Performance and quality
You give a measure before and after.
Collaboration with design
You show how a disagreement turned into a decision.

Examples: each report picks the competencies that fit the role and the interview.

Rehearse this interview out loud

Reading these questions is a start. Saying your answers to someone who follows up is the rehearsal.

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