Full Stack Developers are proficient in both front-end and back-end development, allowing them to build complete web applications independently. Interviewers assess candidates for their technical knowledge across various programming languages, frameworks, databases, and version control systems. This guide includes common Full Stack Developer Interview Questions and Answers to help candidates confidently prepare for their interviews.
Q1. What is a Full Stack Developer?
A Full Stack Developer is a software developer proficient in both client-side (frontend) and server-side (backend) technologies, enabling them to build entire web applications.
Q2. What are the technologies used by Full Stack Developers?
Common technologies include HTML, CSS, JavaScript, React, Angular, Node.js, Express.js, MongoDB, SQL, and Git.
Q3. What is the difference between front-end and back-end development?
Front-end focuses on user interfaces using HTML/CSS/JS, while back-end handles server logic, databases, and application workflows.
Q4. What is RESTful API?
A RESTful API is an application programming interface that follows REST architecture, enabling communication between client and server using HTTP methods.
Q5. What is the use of Node.js?
Node.js is a JavaScript runtime used to build scalable network applications, especially for back-end development.
Q6. What is Express.js?
Express.js is a lightweight web application framework for Node.js used to build robust APIs and web applications.
Q7. What is the Virtual DOM?
The Virtual DOM is a lightweight copy of the actual DOM used in libraries like React to optimize UI rendering.
Q8. What is CORS and why is it important?
CORS (Cross-Origin Resource Sharing) is a mechanism that allows restricted resources on a web page to be requested from another domain.
Q9. How do you manage state in React?
State in React is managed using useState, useReducer, context API, or state management libraries like Redux.
Q10. What is MongoDB?
MongoDB is a NoSQL database that stores data in flexible, JSON-like documents, enabling fast and scalable data handling.
Q11. What is SQL and how is it used in full stack development?
SQL (Structured Query Language) is used to manage and manipulate relational databases like MySQL or PostgreSQL.
Q12. What is version control and which tool is commonly used?
Version control tracks code changes over time. Git is the most commonly used version control tool, often with GitHub or GitLab.
Q13. What is JWT and why is it used?
JWT (JSON Web Token) is used for securely transmitting information between parties, commonly in authentication systems.
Q14. How do you handle errors in Express.js?
Errors in Express.js can be handled using middleware functions with error parameters like (err, req, res, next).
Q15. What is middleware in Express?
Middleware functions are functions that have access to the request and response objects and can modify them or end the request-response cycle.
Q16. What is the purpose of React hooks?
React hooks allow you to use state and lifecycle features in functional components.
Q17. What are props in React?
Props (short for properties) are inputs to React components that allow data to be passed from parent to child components.
Q18. What is the difference between PUT and PATCH in REST APIs?
PUT replaces the entire resource, while PATCH updates specific fields of the resource.
Q19. What is Docker and how is it used in development?
Docker is a containerization tool that packages applications and their dependencies into containers for consistent deployment.
Q20. What is continuous integration?
Continuous integration (CI) is a development practice where developers frequently integrate code into a shared repository with automated testing.
Q21. What are environment variables and how are they used?
Environment variables store configuration data that can be used in your application to separate code from environment-specific settings.
Q22. What is the role of Webpack in React?
Webpack is a module bundler that compiles JavaScript modules and assets into optimized bundles for browser use.
Q23. What is the difference between localStorage and sessionStorage?
localStorage persists data even after the browser is closed, whereas sessionStorage clears data once the session ends.
Q24. How do you secure a web application?
By using HTTPS, sanitizing inputs, implementing authentication and authorization, using secure tokens, and preventing XSS and CSRF attacks.
Q25. What is MVC architecture?
MVC (Model-View-Controller) is a software design pattern that separates application logic, user interface, and control logic into separate components.