Front-End Developer interview questions (2026)

Front-end developer interviews test JavaScript & fundamentals, UI & performance, a coding task, and collaboration. Then practice them in a free AI mock interview tailored to your exact role.

JavaScript & fundamentals

• Explain the difference between the DOM and the virtual DOM.
• How does the event loop work, and why does it matter?
• What causes layout shift, and how do you prevent it?

UI, CSS & performance

• How would you make a slow page load faster?
• How do you build a layout that works on any screen size?
• How do you make a component accessible?

Coding & collaboration

• Build a small component live — talk me through your choices.
• How do you manage state in a complex UI?
• How do you work with designers when a mockup can't be built as-is?