Interview questions
Full Stack Developer interview questions
53 realistic questions across technical, behavioural, HR, situational and role-specific categories. Questions only — join free to unlock model answers, quizzes and AI mock interviews.
Showing 25 of 53 questions
How would you fix a layout issue where a webpage looks correct on desktop but breaks on mobile devices without duplicating CSS?
Technical
Beginner
Q1
Can you explain how closures in JavaScript helped you solve a real-world problem in your project?
Technical
Beginner
Q2
How would you resolve a merge conflict in Git when two developers modify the same file simultaneously?
Technical
Beginner
Q3
How would you design and consume a RESTful API to allow clients to create, read, update, and delete user profiles?
Technical
Intermediate
Q4
How would you implement a REST endpoint in Express.js to handle user login with proper error handling?
Technical
Intermediate
Q5
How did choosing between SQL and NoSQL databases impact the scalability or performance of a project you worked on?
Technical
Intermediate
Q6
How would you implement state management in a React application to handle user input and API data efficiently?
Technical
Intermediate
Q7
How would you implement JWT-based authentication and role-based authorization in a full stack application?
Technical
Advanced
Q8
How would you identify and fix a performance bottleneck in a web application to improve scalability?
Technical
Advanced
Q9
How would you design a scalable full stack system to handle millions of users with real-time updates?
System Design
Expert
Q10
How would you use a hash map to optimize the lookup of user data in a large dataset?
Technical
Intermediate
Q13
How would you build a dynamic form in React that updates fields based on user input?
Technical
Intermediate
Q16
How would you design a backend API and database schema to support a blog platform with posts, comments, and user profiles?
Technical
Intermediate
Q17
Can you describe how you implemented security best practices to protect user data in an application?
Technical
Advanced
Q18
How would you write and run tests to debug a failing React component that doesn’t render user data correctly?
Technical
Advanced
Q19
How would you design a web application architecture to handle 10,000 concurrent users with high availability and fault tolerance?
System Design
Expert
Q20
How would you refactor a legacy JavaScript codebase to use modern ES6+ features while ensuring compatibility and maintainability?
Technical
Beginner
Q22
How would you handle Frontend Frameworks and State Management on a typical day?
Role Specific
Intermediate
Q23
What would you do if you had to deal with Backend Development and RESTful APIs at short notice?
Role Specific
Intermediate
Q24
How would you handle Authentication, Authorization, and Security on a typical day?
Role Specific
Intermediate
Q26
How would you debug a production issue where a web page intermittently fails to load scripts correctly?
Technical
Intermediate
Q27
How would you demonstrate DevOps and Continuous Integration/Deployment to an interviewer?
Professional Specific
Advanced
Q28
How would you design a scalable backend system to process and store millions of user-generated events per day?
System Design
Advanced
Q29
What would you do if you had to deal with Web Performance Optimization at short notice?
Role Specific
Advanced
Q30
Can you describe a situation where your understanding of JavaScript event handling and DOM manipulation helped you solve a critical frontend bug?
Technical
Beginner
Q32
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