Home›Question Bank› Frontend Developer

Frontend Developer Interview Questions and Answers

Frontend interviews mix JavaScript and browser fundamentals, a framework such as React, performance and accessibility, a coding or UI exercise, and front-end system design. Behavioural questions about working with designers and product come up in most loops.

Below are 52 questions asked in frontend developer interviews, each with a sample answer and tips. Read the answer, then practise it out loud: InterviewGuru's AI mock practice scores your spoken or typed answer out of 10 and shows what to improve.

🎯 What interviewers look for
  • Solid fundamentals: the event loop, closures, the DOM, rendering and the network waterfall
  • Framework understanding beyond syntax: state, re-renders, effects and when to memoise
  • Performance work you can measure: Core Web Vitals, bundle size, lazy loading, caching
  • Accessibility and semantics treated as part of the job, not an afterthought
  • Front-end design: component boundaries, data fetching, error and loading states, testing
Behavioral (9)
Give an example of a time you received critical constructive feedback. How did you handle it?Easy Describe a project where you had to learn a completely new technology under tight deadlines.Medium Tell me about a time you identified a technical debt problem and successfully advocated to fix it.Medium Tell me about a time you had to balance feature delivery speed against code quality.Easy Tell me about a time you resolved a major disagreement with a product manager.Medium Tell me about a complex bug that took days to track down. How did you diagnose and solve it?Hard Tell me about a time you handled a disagreement within your own engineering squad.Medium Tell me about a time you optimized an application's performance. What was your approach?Medium Describe a time you proactively prevented a customer-facing issue before it occurred.Easy
Culture Fit (4)
Why do you want to work at our company specifically?Easy How do you stay updated with emerging technologies and decide when to adopt them?Easy What does taking 'extreme ownership' of a feature mean to you in practice?Medium Tell me about a time you had to champion customer empathy when engineers prioritized technical elegance over user needs.Medium
Teamwork (5)
Tell me about a time you collaborated with a cross-functional partner (e.g., designer or product manager) to solve a tough problem.Medium Describe a situation where you had to rely on a teammate's work that was delivered late. How did you handle it?Medium How do you handle code reviews when you disagree with an approach suggested by a senior teammate?Medium Tell me about a time you gave up ownership of an idea or project to support a better team solution.Medium How do you navigate working with a team member who is resistant to adopting new engineering standards?Medium
HR Screening (4)
Tell me about yourself and walk me through your background.Easy What are your greatest professional strengths and your biggest area for growth?Easy Where do you see yourself in three to five years?Easy What motivates you most in your day-to-day engineering work?Easy
Job Offer Negotiation (5)
How do you counter an initial job offer respectfully to negotiate a higher base salary?Medium How do you handle an exploding job offer with a short 48-hour deadline?Medium How do you negotiate remote work flexibility or flexible working hours in a job offer?Easy How do you negotiate an early performance or compensation review cycle into your offer?Medium What should you do after an employer accepts your negotiated counteroffer?Easy
Product Sense (10)
How would you improve the onboarding experience for a complex B2B SaaS dashboard?Medium How would you design a digital tipping feature for an on-demand food delivery platform?Easy How would you decide whether to build a dark mode feature for our web application?Easy How would you measure the success of a newly launched real-time collaboration feature?Medium How would you design a search and discovery experience for an online developer community?Medium How would you design an AI-powered code review feature in a pull request workflow?Hard How would you redesign the settings page of an application that has grown cluttered over years of feature additions?Medium How would you design a customer feedback collection system that gathers actionable insights without annoying users?Easy How would you design an activity feed for a team collaboration platform?Medium If our core conversion funnel drops significantly on mobile compared to desktop, how would you approach redesigning it?Medium
System Design (2)
Design a real-time collaborative document editing service.Hard Design an auto-complete / search typeahead system.Medium
Technical (10)
Explain the JavaScript Event Loop and the difference between microtasks and macrotasks.Medium How does React's Virtual DOM reconciliation and Fiber architecture work?Medium What is Cross-Origin Resource Sharing (CORS), and how do preflight requests work?Medium What are CSS Specificity, the Box Model, and BFC (Block Formatting Context)?Easy What is a Memory Leak in web applications, and how do you diagnose and fix it?Medium Explain the differences between WebSockets, Server-Sent Events (SSE), and Long Polling.Medium What is GraphQL, and how does it compare to REST APIs? What is the N+1 problem in GraphQL?Medium Explain Web Performance Metrics (Core Web Vitals): LCP, INP, and CLS.Medium How does Garbage Collection work in V8 (JavaScript) or modern runtimes?Hard What is Content Security Policy (CSP), and how does it prevent Cross-Site Scripting (XSS)?Medium
Coding (3)
Given an array of integers `nums` and an integer `target`, return indices of the two numbers that add up to `target` (Two Sum).Easy Given a string `s` containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid (Valid Parentheses).Easy Find the longest substring without repeating characters in a given string `s`.Medium

Practise out loud with AI feedback

Answer any of these questions by voice or text and get a score out of 10 with strengths and improvements.

Start practising
📚 Questions for other roles
Product Manager Interview Questions and Answers Engineering Manager Interview Questions and Answers Backend Developer Interview Questions and Answers Data Science and Data Engineering Interview Questions UX and Product Designer Interview Questions and Answers System Design Interview Guide