Full-Stack Developer Interview Questions and Answers
Intermediate / 1 to 5 years experienced level questions & answers
Ques 1. Explain the concept of RESTful APIs.
REST (Representational State Transfer) is an architectural style for designing networked applications. RESTful APIs use standard HTTP methods (GET, POST, PUT, DELETE) for communication.
Ques 2. Explain the Same-Origin Policy and how it affects AJAX requests.
The Same-Origin Policy restricts web pages from making AJAX requests to a different domain than the one that served the web page, for security reasons.
Ques 3. Explain the concept of virtual DOM in React.js.
The virtual DOM is an in-memory representation of the real DOM elements in a React application. It allows React to efficiently update and render components.
Ques 4. What is CORS, and how does it affect web development?
CORS (Cross-Origin Resource Sharing) is a security feature that controls how web pages in one domain can request and interact with resources from another domain.
Ques 5. Explain the role of webpack in a Full-Stack development environment.
Webpack is a module bundler that transforms and bundles assets, such as JavaScript, CSS, and images, for efficient loading in web applications.
Ques 6. Explain the concept of token-based authentication.
Token-based authentication involves issuing a token (usually a JSON Web Token or JWT) to authenticated users, which is then included in subsequent requests for authorization.
Ques 7. What is MVC architecture, and how does it relate to Full-Stack development?
MVC (Model-View-Controller) is a design pattern that separates an application into three interconnected components: Model (data and business logic), View (user interface), and Controller (handles user input and updates the model).
Ques 8. What is GraphQL, and how does it differ from RESTful APIs?
GraphQL is a query language for APIs that allows clients to request only the data they need. It differs from REST by providing more flexibility and reducing over-fetching or under-fetching of data.
Ques 9. What is the purpose of Docker in Full-Stack development?
Docker is a containerization platform that allows developers to package applications and their dependencies into containers, ensuring consistency across different environments.
Ques 10. What are WebSockets, and how are they used in Full-Stack development?
WebSockets provide a full-duplex communication channel over a single, long-lived connection, enabling real-time communication between clients and servers.
Ques 11. Explain the concept of state management in front-end frameworks like React or Angular.
State management involves managing and updating the state (data) of a web application, ensuring that changes are reflected in the user interface.
Ques 12. Explain the concept of the Single Page Application (SPA).
SPAs load a single HTML page and dynamically update the content as the user interacts with the application, providing a smoother and more responsive user experience.
Ques 13. Explain the concept of JWT (JSON Web Token) and its use in authentication.
JWT is a compact, URL-safe means of representing claims to be transferred between two parties. It is commonly used for authentication by securely transmitting information between parties.
Ques 14. Explain the concept of dependency injection in Full-Stack development.
Dependency injection involves providing a component with its dependencies rather than allowing it to create them. It enhances modularity and testability in code.
Ques 15. What are the advantages of using a NoSQL database over a traditional relational database?
NoSQL databases provide flexibility, scalability, and better performance for certain types of applications by allowing the storage of unstructured or semi-structured data.
Ques 16. What is the role of a reverse proxy in a Full-Stack development environment?
A reverse proxy handles client requests and forwards them to the appropriate backend server, improving security, load balancing, and performance.
Ques 17. Explain the concept of serverless architecture and its advantages.
Serverless architecture allows developers to build and run applications without managing servers. Advantages include cost efficiency, automatic scaling, and reduced operational overhead.
Ques 18. What is the role of a load balancer in a Full-Stack development environment?
A load balancer distributes incoming network traffic across multiple servers to ensure no single server is overwhelmed, improving performance and reliability.
Ques 19. What is the purpose of middleware in a Full-Stack development framework like Express.js?
Middleware functions in Express.js handle tasks such as authentication, logging, and error handling. They are executed in the request-response cycle before the final request handler.
Ques 20. What is the purpose of a web server and how does it differ from an application server?
A web server handles HTTP requests, serving static content, while an application server executes application code, handling dynamic content and business logic.
Ques 21. Explain the concept of progressive web apps (PWAs) and their benefits.
PWAs are web applications that provide a native app-like experience, including offline functionality, push notifications, and fast loading times. Benefits include improved user engagement and performance.
Ques 22. Explain the concept of cross-site request forgery (CSRF) and how to prevent it.
CSRF is an attack where an attacker tricks a user's browser into making an unintended request. Prevention methods include using anti-CSRF tokens and checking the referer header.
Ques 23. Explain the concept of two-factor authentication (2FA) and its importance in security.
2FA adds an extra layer of security by requiring users to provide two different authentication factors (e.g., password and a temporary code sent to their phone) before accessing an account.
Ques 24. What is the role of the CDN in the context of caching in web development?
CDNs use caching to store copies of content in multiple locations, reducing server load and improving content delivery speed by serving cached content from the nearest server.
Ques 25. Explain the concept of OAuth and its use in authentication.
OAuth is an open standard for access delegation, allowing users to grant third-party applications limited access to their resources without sharing their credentials.
Ques 26. What is the role of a proxy server in a Full-Stack development environment?
A proxy server acts as an intermediary between client requests and the destination server, providing functionalities such as security, load balancing, and content filtering.
Ques 27. What is the purpose of the 'this.props.children' in React.js?
'this.props.children' in React.js allows components to pass children elements to other components, enabling the composition of complex UI structures.
Ques 28. Explain the concept of A/B testing and its use in optimizing user experiences.
A/B testing involves comparing two versions of a web page to determine which performs better. It helps optimize user experiences by analyzing user behavior and preferences.
Ques 29. What is the purpose of the 'aria-' attributes in HTML and when are they used?
The 'aria-' attributes in HTML are used for accessibility, providing additional information to assistive technologies. They help convey roles, states, and properties to users with disabilities.
Ques 30. Explain the concept of JWT expiration and refresh tokens in authentication.
JWT expiration ensures tokens have a limited validity period. Refresh tokens are used to obtain a new JWT without requiring the user to re-enter their credentials, enhancing security.
Ques 31. Explain the concept of server-side caching and its impact on web application performance.
Server-side caching involves storing copies of dynamically generated content on the server to reduce the need for repeated processing. It improves performance by delivering cached content instead of regenerating it for each request.
Ques 32. Explain the concept of GraphQL subscriptions and how they differ from queries and mutations.
GraphQL subscriptions enable real-time data updates by establishing a persistent connection between the client and server. They differ from queries and mutations, which are used for fetching and modifying data, respectively.
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