Top Full Stack Developer Interview Questions & Answers | SPOTO

Whether you're preparing for your first job interview or leveling up your career, having the right preparation makes all the difference. This comprehensive resource covers the most common and challenging Interview Questions and Answers across a wide range of roles and industries — from technical positions to managerial and entry-level jobs. Browse our curated lists of Frequently Asked Interview Questions, behavioral interview questions and answers, situational interview questions, and role-specific interview prep guides designed to help you walk into any interview with confidence. Whether you're looking for IT interview questions and answers, project management interview questions, or top interview questions for freshers, our expert-reviewed content gives you real-world sample answers, proven tips, and insider strategies to help you stand out.
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Comparison between Java and Python

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here's the difference between Java and Python: Pointers Java Python - Code Java has longer code lines Fewer lines of code are generally used in Python - Working Speed Java is faster in speed as compared to Python It uses an interpreter hence it is slower and also determines the data type at run time Data Types Static Dynamic - Inheritance Partially supports multiple inheritances through interfaces Supports multiple inheritance - Framework Java has a large number of Frameworks. The popular Frameworks are Spring, Hibernate, etc. Compared to Java, Python has a lower number of Frameworks. The popular ones are Django and Flask - Syntax The syntax is complex. Errors can be found if you miss semicolons or curly brackets. The syntax is easy to remember. It is similar to human language. - Databases Java Database Network (JDBC) is broadly used to connect with databases. - Key Highlights Self-memory management, Robust, Platform independent Less line no.

What does display:inline-block do?

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Inline-block uses both properties: block and inline. So, this property aligns the div inline but the difference is it can edit the height and the width of the block. Basically, this will align the div both in the block and inline fashion. CSS | Display property

GeeksforGeeks

display: Inline-block; property

BLOCK 1

BLOCK 2

BLOCK 3

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Which symbol is used for comments in JavaScript?

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Comments prevent the execution of statements. Comments are ignored while the compiler executes the code. There are two type of symbols to represent comments in JavaScript: - Double slash: It is known as a single-line comment. // Single line comment - Slash with Asterisk: It is known as a multi-line comment. /* Multi-line comments . . . */

What is a prompt box?

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The prompt box is a dialog box with an optional message prompting the user to input some text. It is often used if the user wants to input a value before entering a page. It returns a string containing the text entered by the user, or null.

Tell Me Something That Is Not on Your Resume.

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Here are a few ways of answering this question: What Attracted You To This Role: Explain where you came across the job posting, why it got you excited, and why you think that you are a perfect fit for the role. An Instance Where You Went the Extra Mile: Go into an instance in one of your previous jobs where you went above and beyond the responsibilities of your role. Maybe you took the initiative to optimize an application and wrote the code yourself, or established a mentoring program for junior developers and interns. Talk About a Personal Quality That Matches a Job Requirement: Any hobbies or strengths that you have that are relevant to the job that you're applying to can be worth mentioning in your answer to this question.

What are CSS preprocessors, and why are they used?

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CSS preprocessors like SASS and LESS extend CSS with additional features such as variables, nested rules, and mixins. These tools make writing and maintaining CSS easier, especially for large projects. They help streamline code and provide more flexibility and control over the styling process.

What is the JavaScript Event Loop?

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The event loop manages JavaScript's asynchronous behavior. It handles multiple tasks using: - Call Stack - Web APIs - Callback Queue Understanding the event loop is essential for writing efficient backend code, especially in Node.js.

How would you handle a situation where an application needs to be scalable?

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Implementing microservices, using load balancers, optimizing databases, and ensuring stateless application design are some strategies.

What Is Your Favorite Language and Why?

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Deliver your answer in a way that reflects your passion for the field. Maybe you love the intuitiveness of Python syntax, or maybe you really enjoy creating front-end animations using Javascript. If that's the case, then you can dive right into explaining why you enjoy a particular programming language. If you don't have a ready answer, spend time thinking about the projects you've worked on and the languages that you are most comfortable with.

What is an ORM (Object-Relational Mapping), and why is it useful?

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An ORM is a programming technique that allows developers to interact with databases using object-oriented programming languages instead of SQL queries. It maps database tables to classes and simplifies data manipulation. Examples include Sequelize for Node.js, Hibernate for Java, and Entity Framework for C#. ORMs increase productivity by reducing the need to write raw SQL queries and ensuring better maintainability.

How Has Your Experience Prepared You for This Position?

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The key to answering this question is to be familiar with the role and the company. What is the company trying to achieve in the short term? What does the job description say they're looking for in a full-stack developer? Once you know this, you can cherry-pick instances from your past which demonstrate that you're the right person for this role.

What do you like to do outside of work?

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"I enjoy hiking and landscape photography. It helps me disconnect from the digital world and appreciate the beauty of nature. I also volunteer at a local coding club for kids, which is incredibly rewarding."

What are the five SOLID principles of object-oriented design?

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The five SOLID principles are: S – Single Responsibility Principle (SRP): A class should have only one job or responsibility; O – Open/Closed Principle (OCP): Software entities need to be open for extension but closed for modification; L – Liskov Substitution Principle (LSP): Objects of a superclass should be replaceable with objects of a subclass without affecting the correctness of the program; I – Interface Segregation Principle (ISP): Clients should not have to depend on interfaces they don't use; D – Dependency Inversion Principle (DIP): High-level modules should not depend on low-level modules but instead on abstractions.

How do you handle feedback and criticism in your development process?

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Talk about code reviews from your instructors and peers. Share how you have used feedback to improve your code and grow as a developer. Why This Matters Your ability to accept and implement feedback is crucial for professional growth and team harmony.

Why do developers use Geolocation API in HTML5?

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Geolocation API allows engineers to capture a website user's location. The API tracks the latitude and the longitude of a user's location and sends this data back to the server. The practical applications of Geolocation API are showing a website visitor her location on the map or letting users know which businesses are located in the area.

What Is Something You Like To Do Outside of Work?

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Give an honest answer. Don't exaggerate your volunteer experience or say that you want to backpack around the world if that's not who you are. You can list more mundane things, like hanging out with your dog, if that's what you really enjoy.

What is responsive design? What are its best practices?

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Responsive design is an approach to application design that aims to create interfaces that fit various screen dimensions. Given that there are over 20,000 smartphone and computer display sizes, it's not a challenge-free process. Here are the practices full-stack developers and designers use to improve responsiveness: - Adding at least three CSS breakpoints. - Prioritizing content by importance ensuring that the most relevant blocks are the most accessible ones. - Making the size of buttons around 44×44 pixels.

How do you handle security vulnerabilities such as SQL injection and XSS?

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To avoid SQL injection attacks, use parameterized queries or prepared statements to prevent malicious SQL code from being executed: Also validate and sanitize user inputs to ensure it doesn't contain characters that might interfere with SQL statements. To avoid allowing scripts or dynamic content to affect your page: Escape content before rendering in the browser: Use libraries like DOMPurify to sanitize HTML. Set Content-Security-Policy headers to restrict allowed sources for scripts to trusted sources.

What's your favorite language, and why?

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Usually, interviewers ask this question at the beginning of the interview to get candidates warmed for the entire interview process. This question helps them assess their inclination towards working with multiple programming languages. Since Full Stack Developers are required to work with multiple technologies and applications, they must be well-versed in at least two or three programming languages, including the most trending ones (Java, Python, R, etc.). So, if you answer this question blatantly stating your love for just one programming language, it is a red flag for the interviewer. Even if you haven't mastered multiple programming languages, interviewers love candidates who are open to learning and experimenting with new languages.

Which language is the most preferred by Java Full Stack Developers?

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Java itself is the first and foremost language that is preferred. Along with it, the Java full-stack developer should be proficient in other popular programming languages such as Python, Ruby, PHP, C++, etc.

What Factors Do You Need for Successful Integration?

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Below are the main factors that determine whether an integration happens successfully: - Data quality - Extent of customization - Consolidation of approaches - Future-proofing - Support of top management.

Differentiate between Monolithic and Microservices architecture.

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Explain Long Polling

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Long polling is a technique where the server maintains and manages a connection with the client until new data is available. It is used for real-time applications, allowing instant updates without the need for constant client requests. e.g. chat applications, stocks, or multiplayer games.

How do you prevent SQL injection and other common security vulnerabilities in database queries?

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To prevent SQL injection, I use parameterised queries or prepared statements with ORM libraries instead of raw string concatenation. Input validation and sanitisation, least privilege access, and regular security audits also help mitigate vulnerabilities like Cross-Site Scripting (XSS) and Cross-Site Request Forgery (CSRF).

How do you manage multiple tasks for a single project at the same time?

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In the case of having multiple projects, I order my tasks by deadlines, impact, and dependencies. Trello or Jira I use to clearly set the tasks at hand in front of me and have clear milestones. I regularly communicate this with the stakeholders so that everyone is on the same page, and as needed, adjust the priorities as needed. Dividing into smaller portions helps me not lose my focus.

What is the difference between ArrayList and LinkedList?

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For what reasons arrow function not be used in ES6?

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Arrow functions should not be used when you need a dynamic 'this' context, such as in object methods, event handlers, or when using arguments object, because arrow functions do not have their own 'this' or 'arguments' binding. They are also not suitable for constructors.

What miscellaneous topics are covered in the interview questions?

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In this part, we discuss general design principles and patterns like SOLID, KISS, and DRY, as well as common data structures and algorithms (DSA) questions. This section is designed to help you understand core programming concepts and how to approach common algorithmic problems in interviews.

What is the purpose of unit testing in software development?

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Unit testing verifies individual functions or components in isolation, ensuring they work as expected. It helps catch bugs early, improves code reliability, facilitates refactoring, and serves as documentation. Tools like Jest, Mocha, and Chai are commonly used.

How is CSS different from CSS 3?

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CSS | CSS3 | |---|---| | CSS is capable of positioning texts and objects. CSS is somehow backward compatible with CSS3. | On the other hand, CSS3 is capable of making the web page more attractive and takes less time to create. If you write CSS3 code in CSS, it will be invalid. | | Responsive designing is not supported in CSS | CSS3 is the latest version, hence it supports responsive design. | | CSS cannot be split into modules. | Whereas, whereas CSS3 can be breakdown into modules. | | Using CSS, we cannot build 3D animation and transformation. | But in CSS3 we can perform all kinds of animation and transformations as it supports animation and 3D transformations. | | CSS is very slow as compared to CSS3 | Whereas, CSS3 is faster than CSS. |

Explain your approach to responsive design.

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Do not just talk about media queries! Share your experience creating mobile-first designs and how you have handled different screen sizes in your projects. Assignments where you had to make your sites work on everything from phones to desktop monitors are perfect examples to showcase. Why This Matters With mobile traffic dominating the web, responsive design is not optional anymore – it is essential.

What is the difference between a REST API and a GraphQL API?

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REST APIs expose fixed endpoints and return predefined data formats, while GraphQL allows clients to request only the data they need from a single endpoint, offering more flexibility and efficiency in terms of data retrieval.

Describe the differences between React and Angular in terms of architecture and use cases.

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React is a component-based library focused on the view layer, using a virtual DOM and unidirectional data flow, ideal for dynamic, single-page applications. Angular is a full-fledged framework with two-way data binding, dependency injection, and a more opinionated structure, suitable for large enterprise applications with complex requirements.

How do you debug an issue in production?

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“I check logs, reproduce the issue locally, analyze stack trace, and use tools like Postman or debugger to trace flow.”

What is the purpose of an index in a database, and when would you use one?

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An index speeds up query performance by allowing faster retrieval of rows, similar to an index in a book. I use indexes on columns frequently used in WHERE clauses, JOINs, or ORDER BY, but avoid over-indexing to prevent slower write operations.

Explain the access modifiers in Java.

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public: Accessible everywhere protected: Within package + subclasses default: Within package only private: Within same class only

What is Thymeleaf?

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Thymeleaf is a Java-based server-side template engine used in Java web applications to render dynamic web pages. It is a popular choice for server-side templating in the Spring ecosystem, including Spring Boot. To know more about Thymeleaf, refer to this article – Spring Boot – Thymeleaf with Example

What is a database trigger, and when would you use it?

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A database trigger is a set of SQL statements that automatically execute or "fire" when certain events occur on a specific table or view (e.g., INSERT, UPDATE, DELETE). Triggers are used to enforce business rules, validate data integrity, or automatically update other tables in response to changes.

Can we add 3D transformations to our project using CSS?

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Yes, it allows changing elements using 3D transformations. In 3D transformation, the elements are rotated along the X-axis, Y-axis, and Z-axis. There are three main types of transformation which are listed below: - rotateX() - rotateY() - rotateZ()

What is full-stack development?

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Full-stack development refers to the practice of building and maintaining both the frontend and backend of a web application or web service. A full-stack developer works across all layers of the application, ensuring seamless functionality from the user interface to the server and database. Key aspects of full-stack development include: Frontend Development: Involves creating the parts of the application that users interact with directly, such as buttons, forms, and layouts. Tools and technologies often used include HTML, CSS, JavaScript, and frameworks like React, Angular, or Vue.js. This may also include building Progressive Web Apps (PWAs) for enhanced user experiences. Backend Development: Focuses on server-side logic, databases, and APIs that power the frontend. Common programming languages for backend development include Python, Java, Node.js, and PHP. Developers often design and integrate web services or REST/GraphQL APIs for data handling. Databases and Storage: Managing data through relational databases (e.g., MySQL, PostgreSQL) or non-relational databases (e.g., MongoDB, Redis). DevOps and Deployment: Setting up hosting environments, CI/CD pipelines, and handling cloud services to deploy and maintain applications. Full-stack developers are valued for their versatility and ability to understand how different components of a web application interact, making them crucial for delivering well-rounded, functional products.

Walk me through how you would optimize a slow database query.

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First, I'd identify which queries are actually slow using database logs or an APM tool like New Relic. Let's say I find a query that's taking 3 seconds to return user posts with comment counts. I'd start by running EXPLAIN on the query to see the execution plan—is it doing full table scans? Next, I'd check if proper indexes exist. For a query joining users, posts, and comments, I'd want indexes on foreign keys and commonly filtered columns. If the query is complex, I might rewrite it—sometimes breaking a complex join into multiple simpler queries is faster, especially if I can cache intermediate results. I'd also consider whether I need all that data—maybe I can paginate or lazy load. For frequently accessed data like user profiles, I'd implement Redis caching. Finally, I'd measure the impact of each optimization to make sure I'm actually improving performance, not just making the code more complex.

How do you monitor the health and performance of a production web application?

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I use monitoring tools like Prometheus and Grafana for metrics, and ELK stack (Elasticsearch, Logstash, Kibana) for log analysis. Application Performance Monitoring (APM) tools like New Relic track response times and errors. I set up alerts for anomalies like high latency or downtime, and perform regular health checks.

How to get the status of a CheckBox?

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The DOM Input Checkbox Property is used to set or return the checked status of a checkbox field. This property is used to reflect the HTML Checked attribute. document.getElementById("GFG").checked; If the CheckBox is checked then it returns True.

Explain the components of a react-router

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The main components of a react-router are - Router(usually imported as BrowserRouter): It is the parent component that is used to store all of the other components. Everything within this will be part of the routing functionality - Switch: The switch component is used to render only the first route that matches the location rather than rendering all matching routes. - Route: This component checks the current URL and displays the component associated with that exact path. All routes are placed within the switch components. - Link: The Link component is used to create links to different routes.

Explain Spring MVC

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MVC stands for Model, View, and Controller. Spring MVC is a web MVC framework built on top of the Spring Framework. It provides a comprehensive programming model for building web applications.

What Do You Mean by Data Attributes?

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A data attribute is a descriptor of a data object.

What is MVC architecture?

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MVC stands for Model-View-Controller. It separates application logic into three interconnected components to organize code and promote scalability and maintainability.

Explain the purpose of a version control system and Git workflow?

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Purpose: Version control tracks changes in code, enables collaboration, and allows reverting to previous versions. Git Workflow Example: - Clone the repository: git clone . - Create a branch: git checkout -b feature-branch . - Make changes and stage them: git add . . - Commit changes: git commit -m "Add feature" . - Push to the remote: git push origin feature-branch . - Create a pull request for review. - Merge the branch into the main branch after approval.

What is Middleware?

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Middleware is code that executes between a client request and the server response. It helps manage tasks like: - Logging - Authentication - Error handling - Request body parsing Frameworks like Express.js, Django, and Spring rely heavily on middleware to structure server logic efficiently.

Walk me through the steps you take to optimize a website's performance.

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Candidates should discuss practices such as minimizing HTTP requests, optimizing images, using CDNs, caching strategies, and JavaScript bundling.

Given the following frontend code, identify any issues: fetch('/api/data') .then(response => response.json()) .then(data => console.log(data)) .catch(error => console.error('Error fetching data:', error));

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The code fetches data from the /api/data endpoint and logs it to the console. One potential oversight is that it assumes a successful HTTP response contains valid JSON. It's a good practice to first check response.ok before parsing the JSON to handle potential server errors.

What would you do if you accidentally committed sensitive data into a public git repository? Walk me through the steps to resolve this.

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The candidate should display an understanding of the security implications and be able to provide a detailed procedure on cleaning up the history and mitigating the impact of the sensitive data exposure.

What is the purpose of the Bridge Pattern?

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Bridge Pattern is used for situations that require an abstraction to be decoupled from its implementation to allow the two to stand independently. This pattern is useful when the class and its functions vary. While the class is considered as an abstraction, its function is considered as implementation. In this pattern, an interface is leveraged that acts as a bridge, liberating the functionality of concrete classes from interface implementer classes. Thus, both classes can be manipulated/altered without affecting one another.

What Is Polling?

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You'll be tested with several field-related questions. So, if the interviewer asks you a few in a row, it's no surprise. Get hold of yourself and answer patiently. They would be general questions for the most part. “Polling refers to when a client repeatedly asks the server for new data. It can be long polling or short. The former passes the data from the server to the client without delay. The latter, on the other hand, is AJAX-based and involves fixed delays.”

How do you handle file uploads and storage?

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Candidates should explain multipart uploads, validation, virus scanning, cloud storage (S3), and CDN delivery. They should mention size limits, format restrictions, and progress indicators for better UX.

How do you stay current with new technologies and industry trends?

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The world of development is ever-changing. The candidate should have a current knowledge of the field and a desire to keep learning as it evolves. If they're not in tune with the tech community, working on independent projects, or brushing up on their skills, they may not be a forward-thinking employee.

Describe a challenging project you have ever worked on and how you handled that project.

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Choose a project that was full of problems—e.g. one with a completely unrealistically short time frame, technical problems, or disagreements between team members. Try to explain the situation, what descriptions of one's approach to handling such issues look like, and its outcome. Consider what was learned from your past experience and how the person has increased as a result of it.

Describe the importance of CORS in web development.

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CORS (Cross-Origin Resource Sharing) is a security feature implemented by web browsers that controls how web pages in one domain can request resources from another domain. Without CORS, the Same-Origin Policy would prevent AJAX requests to different domains. For APIs and services to be accessed from different origins (domains, protocols, or ports), the server needs to include appropriate CORS headers (like Access-Control-Allow-Origin) in its response to permit these cross-origin requests.

What is the purpose of JavaScript event delegation?

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Event delegation is a technique in JavaScript where a single event listener is added to a parent element instead of individual child elements. The event is propagated (bubbled) to the parent, where it is handled. This improves performance and simplifies code, especially when working with dynamic content. Example: parent.addEventListener('click', function(event) { if(event.target.matches('button')) { /* handle button click */ } });

What is REST API?

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Answer: REST (Representational State Transfer) is an architectural style for web services. Example: GET /students → fetch list POST /students → create record PUT /students/{id} → update DELETE /students/{id} → delete

What Technical Skills Should a Full-Stack Developer Possess?

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This is a tricky one. The recruiter wants to know YOUR technical skills, not those of some random full-stack developer. Carefully think through the answer and respond. “I think full-stack developers are the jack of all trades. Therefore, the list of technical skills is rather long. They must have a hang of programming languages like Python, Java, Ruby, PHP, C++, etc. Besides, knowledge regarding front-end frameworks like bootstrap, JavaScript, ReactJS, and back-end frameworks like NodeJS, Express, Django, etc., is vital. They must also understand popular databases and have excellent designing ability to become a successful full-stack developer.”

What is a data attribute and how to use it?

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Data is a custom attribute defined by a developer. It applies whenever there's no suitable characteristic a developer would rather use. Data is active only for the page where it's defined and doesn't require AJAX calls for running.

What is Docker?

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Containerization platform that packages application with dependencies to run anywhere.

What is Spring Boot?

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Spring Boot is built on top of the Spring framework to create stand-alone RESTful web applications with very minimal configuration and there is no need of external servers to run the application because it has embedded servers like Tomcat and Jetty etc. - Spring Boot framework is independent. - It creates executable spring applications that are production-grade.

What are undeclared and undefined variables?

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- Undefined: It occurs when a variable is declare but not assign any value. Undefined is not a keyword. - Undeclared: It occurs when we try to access any variable which is not initialize or declare earlier using the var or const keyword. If we use 'typeof' operator to get the value of an undeclare variable, we will face the runtime error with the return value as "undefined". The scope of the undeclare variables is always global.

Your monolithic full-stack application is becoming unwieldy. The team decides to migrate to a microservices architecture. What are the biggest challenges you anticipate from a full-stack perspective (both front-end and back-end integration), and how would you mitigate them?

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Your understanding of distributed systems challenges (e.g., data consistency across services, network latency, distributed transactions, service discovery, robust error handling across services). They want to know how these complexities impact both the backend interview questions layer and the consuming frontend interview questions for a seamless experience.

What is the concept of HTTP/2 and HTTP/3, and how do they improve performance?

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HTTP/2 and HTTP/3 are improved versions of HTTP designed to enhance web performance. HTTP/2 Enhancements: - Multiplexing: Sends multiple requests over a single connection. - Header compression: Reduces overhead. - Server push: Sends responses before requests to speed up page load. HTTP/3 (QUIC-based) Enhancements: - Uses UDP instead of TCP for faster connections. - Reduces latency in mobile and unstable networks. - Improves security with built-in encryption.

Explain BSON and Its Significance in MongoDB.

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BSON (Binary JSON) is a binary-encoded serialization format used by MongoDB to store documents. BSON extends JSON by adding support for data types such as dates and binary data and it is designed to be efficient in both storage space and scan speed. The binary format allows MongoDB to be more efficient with data retrieval and storage compared to text-based JSON.

What are the best practices for designing a RESTful API?

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Best practices include: Use URI resources and HTTP methods appropriately; Implement authentication and authorization; Ensure API security (e.g., by using HTTPS, input validation against SQL injection, XSS); Use pagination, sorting, and filtering for large data sets; Write clear, concise documentation for the API.

What are the different CSS border properties?

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CSS border properties allow us to set the style, color, and width of the border. - Border Style: The border-style property specifies the type of border. None of the other border properties will work without setting the border style. - Border Width: Border width sets the width of the border. The width of the border can be in px, pt, cm or thin, medium and thick. - Border Color: This property is used to set the color of the border. Color can be set using the color name, hex value, or RGB value. If the color is not specified border inherits the color of the element itself.

What are some common performance issues in web applications and how do you address them?

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Discuss troubles like slow load times, memory leaks and inefficient database queries. Describe strategies you have used to cope with these issues, which include: - Optimization: Minifying CSS and JavaScript, optimizing pix. - Caching: Using gear like Redis or Memcached. - Database Indexing: Ensuring green queries. - Load Balancing: Distributing traffic throughout a couple of servers.

What is a key in React?

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A "key" is a special string attribute you need to include when creating lists of elements in React. Keys are used in React to identify which items in the list are changed, updated, or deleted. In other words, we can say that keys are used to give an identity to the elements in the lists.

How do you decide between using server-side rendering (SSR) versus client-side rendering (CSR)?

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A strong answer will explain that Server-Side Rendering (SSR) involves generating HTML on the server for each request, which benefits SEO and improves performance on slower devices by delivering pre-rendered content. Client-Side Rendering (CSR), on the other hand, relies on the browser to render the content, allowing for a faster initial load of the app shell but potentially slower content load times and less optimal SEO. They might illustrate a decision process: for static sites or content-heavy pages where SEO is critical, SSR might be the preferred choice (e.g., using Next.js in a React project). For dynamic, interactive applications where frequent user interactions are key, CSR could be more efficient, using frameworks like React or Vue. They could further explain hybrid approaches (e.g., Next.js's support for static generation and SSR) that allow certain pages to be server-rendered while others are rendered on the client for the best of both worlds.

How do you handle feedback and criticism in your development process?

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Talk about code reviews from your instructors and peers. Share how you have used feedback to improve your code and grow as a developer.

What is a Callback Hell?

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- Callback Hell is asynchronous programming code i.e. multiple functions running simultaneously. The term depicts an expansive number of nested “if” statements or functions. In basic terms, Callback Hell is where you would like to apply numerous asynchronous functions. - The callback function leaves you with code that is difficult to read, maintain, and look making it more difficult to identify the flow of the application – the main obstacle to debugging. This is called Callback Hell.

What is HTML, CSS, and JavaScript?

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HTML: Structure of the webpage CSS: Styling and layout JavaScript: Interactivity and logic

How does garbage collector work?

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Mark and sweep: mark: traverse object graph starting from root objects, sweep: garbage collect unmarked objects. Optimizations: young/old generations, incremental mark and sweep

Can you discuss a project where you had to negotiate or persuade others to adopt your approach? What tactics did you use to communicate your perspective?

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Candidates should show their persuasive communication skills along with the ability to advocate for their ideas effectively.

What is the difference between monolithic and microservices architecture?

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What are your professional goals?

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"In the short term, I aim to deepen my expertise in front-end frameworks and contribute to improving our user interfaces. Long term, I hope to lead a development team and help drive innovation within the company."

What is REST and provide an example of its usage.

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What is Bootstrap?

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Bootstrap is a highly convenient resource for front-end developers so full-stack engineers should know about it as well. In a nutshell, it is a library of HTML, CSS, and JavaScript components. Here are the types of components developers can find in Bootstrap: - Grinds. - SaaS variables. - Plugins. - Ready-to-deploy modules. - Plugins. Full-stack developers use Bootstrap both for prototyping and application development.

Tell Us About Something You Learned a Few Days Back

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The interviewer is playing smart, connecting the dots between the two questions and probing about your authenticity. Because you demonstrated you keep yourself updated, they want to know if you learned anything new recently. Refrain from giving the impression that you learned nothing in the past few months. “I read about an intriguing case study regarding a bug. It helped me learn the quickest ways to find the bug source and eliminate it timely. This helped me boost my work efficiency.”

What is HTTP Strict Transport Security (HSTS)?

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Prevents Man in the Middle attacks

Explain the importance and role of WebSockets in modern web applications.

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WebSockets provide a full-duplex communication channel over a single, long-lived connection, enabling real-time functionality. It's more efficient than traditional polling mechanisms and is commonly used in applications that need constant data updates like chat apps, online games, and financial platforms.

What is a critical section?

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A critical section is a specific part of the code where shared resources are accessed or modified. critical section needs to be executed by only one thread at a time to avoid conflicts and maintain data integrity. To success this, synchronization techniques such as synchronized blocks or locks are used

How do you approach performance monitoring in a full-stack application?

Reference answer

As a full-stack developer, the monitoring of your application involves the full 360 view of the app, from the frontend into the backend, including the database, and other involved systems. Use tools like Google Lighthouse or Web Vitals to track load times, interactivity, and rendering. Monitor user behavior with tools like New Relic Browser or LogRocket. Use APM tools (e.g., Datadog, Dynatrace) to monitor server response times, database query performance, and API latency. Centralize logs with tools like ELK Stack or CloudWatch Logs for analyzing bottlenecks. Critical for systems with many individual microservices and different clients working together. Use query profilers (e.g., MySQL EXPLAIN) and monitor database health with tools like Percona Monitoring. Set up alerts for anomalies or thresholds using tools like Prometheus and Grafana.

Do You Have Any Technical Certifications?

Reference answer

Certifications are a great way to learn new skills and distinguish yourself. You can also highlight any capstone projects that you built as part of your certification.

What's the Difference Between Normalization and Denormalization?

Reference answer

Normalization is a method of reducing data redundancy by separating data into multiple tables. Denormalization is the opposite process, where data is consolidated into one table so that it is easier to retrieve. Read more about the normalization and denormalization of database tables.

Describe a situation where you had to troubleshoot a database performance issue in a full stack project. What tools and techniques did you use to identify and solve the problem?

Reference answer

The expectation is that the candidate will explain a real-world problem and their systematic approach to solving it, using tools like query analyzers, explain plans, indexing strategies, or caching. This measures their practical proficiency in database performance optimization in a full stack context.

What are Selectors in CSS?

Reference answer

Selectors in CSS refer to ways which are used to locate a particular HTML element in the CSS file to style. In CSS, there are five types of selectors, which are as follows: - Simple Selectors– In simple selectors, we select elements based on their id, class, and name. - Combinator Selectors– In this, elements are selected based on the relationship between them. - Pseudo-Class Selectors– This selects elements based on their state. - Pseudo-Elements Selectors– This type of selector selects a part of the HTML elements and styles it. - Attribute Selectors– Attribute Selectors are used to styling an HTML element based on its attribute or its attribute value.

How Is Rolling Deployment Different From Blue-Green Deployment?

Reference answer

A blue-green deployment strategy employs two environments, one known as blue and the other as green. The quality assurance processes and testing are done in the blue environment while traffic is directed to the green environment. Rolling deployments don't have different staging environments. They simply deploy updates to running instances as and when required.

Describe Your Typical Day as a Full-Stack Developer In Your Previous Job

Reference answer

Because full-stack developers have a lot on their plate, the recruiter wants to know how you handled everything efficiently at your previous job. “In all honesty, I had to juggle various tasks during my previous role. It was common to jump from coding to fixing a networking problem and meeting clients in a single day. However, my organisational and time management skills helped me multitask without compromising work quality.”

What is the purpose of Docker in application deployment?

Reference answer

Docker enables containerization, which isolates applications, ensuring consistency across development, testing, and production environments.

What is the syntax for CSS?

Reference answer

A CSS style rule consists of a selector, property, and its value. The selector points to the HTML element where CSS style is to be applied. The CSS property is separated by semicolons. Syntax selector { Property: value; }

What do you have to learn about responsive design?

Reference answer

Responsive design ensures web applications adapt seamlessly to a variety of screen sizes and orientations by implementing techniques such as flexible grids and media queries.

Can you describe your experience with NoSQL databases and how you used one in a full stack project? What were the reasons for choosing NoSQL over a relational database?

Reference answer

Expectations are for the candidate to provide a relevant example showing their experience in database management, particularly with NoSQL databases. They should explain the specific use-case that led to choosing NoSQL, such as the need for scalability, non-relational data, or high write speeds, reflecting on their decision-making capabilities.

What are elements and tags in HTML?

Reference answer

- HTML Tags: Tags are the starting and ending parts of an HTML element. They begin with < symbol and end with > symbol. Whatever is written inside < and > are called tags. Syntax - HTML elements: Elements enclose the contents in between the tags. They consist of some kind of structure or expression. It generally consists of a start tag, content, and an end tag. Syntax This is the content.

How to redirect to a particular section of a page using HTML?

Reference answer

One can use the anchor tag to redirect to a particular section on the same page. You need to add "id attribute" to the section that you want to show and use the same id in href attribute with "#" in the anchor tag. So that On click a particular link, you will be redirected to the section that has the same id mentioned in the anchor tag. Syntax home

Information About Page

Example

Welcome to GeeksforGeeks

This is the example of Redirect to a particular section using HTML on same page

Home section

About Us section

Contact Us section

Team Section

- It is an HTML page with headings, paragraphs, and sections inside

elements. - Each section (

) is given a fixed height (400px) and a border for separation. - Clicking the "Contact Us" link jumps to the "Contact Us" section using id="contactUs". - The page has four sections – Home, About Us, Contact Us, and Team, displayed in separate

blocks.

100

What is your greatest strength as a developer?

Reference answer

“I'm consistent and curious. I don't just code; I understand why a feature matters to users.”

101

What is a Lambda Expression in Java?

Reference answer

Introduced in Java 8 - allows concise function expressions. Example: List list = Arrays.asList(1,2,3); list.forEach(n -> System.out.println(n));

102

How do you manage secrets and sensitive data in a DevOps environment?

Reference answer

Secrets management is crucial in DevOps to protect sensitive data like passwords, API keys, and certificates. Tools like HashiCorp Vault, AWS Secrets Manager, and Azure Key Vault help store and manage secrets securely, with controlled access and encryption.

103

Which languages and technologies should a full-stack developer know?

Reference answer

This question will give business owners an immediate understanding of how many types of tools a candidate can work with. Typically, the technologies expected in a full stack engineer job description are: - Front-end and back-end programming languages. The former include HTML, CSS, and JS, while the latter are Java, PHP, Python, and others. A candidate doesn't have to be highly skilled in either – however, a good understanding of syntax and applications will make it easier to collaborate with teammates. - Frameworks. These tools help cut the time needed to bring a product to the market tremendously – that's why it's helpful to hire a candidate familiar with the main ones. The examples of most widely used frameworks are Django, Spring, Hibernate, etc. - Databases are the cornerstone of most software development projects. That's why a full-stack engineer should know how to use at least one DB language – for most candidates, it's SQL. - Prototyping and design tools. Having a toolset for wireframing, as well as UX and UI design is crucial for designing the front-end of the project.

104

What is a repository in Git?

Reference answer

A Git repository (or repo) is like a file structure that stores all the files for a project. It continues track changes made to these files over time, helping teams work together evenly. Git can control both local repositories (on your own machine) and remote repositories (usually hosted on platforms like GitHub, GitLab, or Bitbucket), allowing teamwork and backup.

105

What is CAP theorem?

Reference answer

It is impossible for a distributed computer system to simultaneously provide all three of the following guarantees: consistency, availability, partition tolerance. Gilbert and Lynch's paper. "Please stop calling databases CP or AP").

106

How do you handle internationalization?

Reference answer

Candidates should mention i18n libraries, translating UI and backend messages, date/currency formatting, and RTL support. Look for awareness of locale detection, fallback languages, and content management workflows.

107

Imagine you've been tasked with improving the performance of a slow web application. What steps would you take to diagnose and solve the problem?

Reference answer

Candidates should exhibit an understanding of performance optimization techniques and the ability to diagnose issues using appropriate tools and strategies.

108

Analyze the following GraphQL query: { user(id: "12345") { name email friends { name } } }

Reference answer

This GraphQL query fetches a user with the ID “12345”. For this user, it retrieves their name, email, and the names of all their friends.

109

What Are the Types of Design Patterns?

Reference answer

There are three types of design patterns: creational, structural, and behavioral. Read more about the characteristics of different design patterns.

110

Introduce Yourself.

Reference answer

Give recruiters an idea of your past experience. Talk about what you studied in college, any full-stack web development courses you've taken, and your previous roles. Then, explain why you're interested in this job. This is your chance to show that you've researched the company. Explain how you can bring value to the organization, and how the role can help you achieve your professional goals.

111

How do you test your full stack applications?

Reference answer

I use a testing pyramid approach. For the front-end, I write unit tests for individual components using Jest and React Testing Library, focusing on user interactions rather than implementation details. I also write integration tests that check how components work together. For the back-end, I test my API endpoints with tools like Supertest, mocking external dependencies. I really value end-to-end tests using Playwright for critical user journeys—things like user registration and checkout flows. In my last role, we had about 80% unit tests, 15% integration tests, and 5% E2E tests. I also set up automated testing in our CI/CD pipeline, so every pull request gets tested before it can be merged.

112

Walk me through the most complex full stack feature you've built end to end.

Reference answer

The most complex thing I built was a real-time notification system. On the backend, I set up a Node.js service consuming events from a Kafka topic and pushing updates to connected clients via WebSockets. On the frontend, I built a React context that managed the WebSocket connection lifecycle and fed updates into a notification center component. The hard parts were handling reconnects gracefully, ensuring events weren't missed during downtime, and building a polling fallback for environments where WebSockets weren't stable. I also had to coordinate with the mobile team, who needed the same event stream delivered differently, so I exposed a separate REST endpoint for them. It touched auth, database reads, real-time infrastructure, and cross-team coordination simultaneously.

113

What are hooks in React?

Reference answer

Hooks are a new addition in React 16.8. They let developers use state and other React features without writing a class. Hooks doesn't violate any existing React concepts. Instead, Hooks provide a direct API to react concepts such as props, state, context, refs and life-cycle

114

Describe the concept of AJAX.

Reference answer

AJAX (Asynchronous JavaScript and XML) allows web pages to retrieve data from a server asynchronously without refreshing the page, leading to a better user experience.

115

What is AJAX?

Reference answer

AJAX (Asynchronous JavaScript and XML) allows web pages to communicate with servers without reloading.

116

How and When Would You Clear Floats in CSS?

Reference answer

You can apply the “clear” property to elements when you want to correct floated elements. You can clear a float in three ways: left, right, and both. Let's say you want to clear the float that has been applied to header elements. You would type out the following CSS code to achieve that: header { clear: both; }

117

What are the components of the Java architecture (JVM, JRE, JDK)?

Reference answer

Component | Description JVM | Executes Java bytecode JRE | JVM + essential libraries JDK | JRE + development tools (javac, jar, etc.)

118

What is Pair Programming?

Reference answer

As the name suggests, Pair Programming is where two programmers share a single workstation. Formally, one programmer at the keyboard called the “driver” writes the code. The other programmer is the “navigator” who views each line of the code written, spell check, and proofread it. Also, programmers will swap their roles every few minutes and vice-versa.

119

What is sequential consistency?

Reference answer

The result of any execution is the same as if the operations of all the processors were executed in some sequential order, and the operations of each individual processor appear in this sequence in the order specified by its program.

120

What CSS and SCSS topics are covered in the interview questions?

Reference answer

This article focuses on CSS fundamentals, responsive design, Flexbox, Grid, and SCSS syntax. You'll find questions about styling best practices, animations, z-index, the CSS Box Model, and concepts like CSS Modules and CSS-in-JS, as well as advanced SCSS techniques.

121

What is JSX?

Reference answer

JSX is basically a syntax extension of regular JavaScript and is used to create React elements. These elements are then rendered to the React DOM. All the React components are written in JSX. To embed any JavaScript expression in a piece of code written in JSX we will have to wrap that expression in curly braces {}. Example of JSX: The name written in curly braces { } signifies JSX const name = "Learner"; const element = (

Hello, {name}.Welcome to GeeksforGeeks.

);

122

What is Cross-origin resource sharing (CORS)?

Reference answer

Cross-origin resource sharing (CORS) is a process that utilizes additional HTTP headers to tell browsers to provide a web application running at one origin. CORS accesses various web resources on different domains. Web scripts can be integrated using CORS when it requests a resource that has an external origin (protocol. Domain, or port) from its own.

123

What is your experience with databases?

Reference answer

Discuss your experience with databases like MySQL, MongoDB, or PostgreSQL, and emphasize your ability to create, maintain, and perform CRUD operations. Tailor your response based on the specific database needs of the company you're interviewing with.

124

What is the difference between an alert box and a confirmation box?

Reference answer

An alert box will display only one button which is the OK button. It is used to inform the user about the agreement has to agree. But a Confirmation box displays two buttons OK and cancel, where the user can decide to agree or not.

125

Share a scenario where you applied a design pattern to solve a recurrent problem in your development work. Which pattern did you choose and why?

Reference answer

The candidate should be able to explain the rationale behind choosing a particular design pattern to solve a problem, demonstrating a grasp of the pattern's use case and benefits.

126

Explain the concept of REST API to a non-technical person.

Reference answer

“It's like a waiter who takes your order (request) and brings you food (response) from the kitchen (server).”

127

Elaborate the difference between blue/green deployment and rolling deployment?

Reference answer

Blue/green deployment involves maintaining two identical production environments (blue and green). One environment serves live traffic while the other is updated. After testing, traffic is switched to the updated environment. Rolling deployment updates instances one by one or in small batches, gradually replacing the old version with the new one without downtime.

128

Discuss the benefits and potential drawbacks of using a monorepo versus multiple repositories for managing a full stack project.

Reference answer

The candidate is expected to evaluate the organizational choices for version control in the context of a full stack project, taking into account factors like project size, complexity, and team collaboration.

129

Explain Flexbox vs Grid

Reference answer

- Flexbox: Best for one-direction (row or column) layouts. - Grid: Best for two-direction (rows and columns) layouts. Both are essential for modern responsive design.

130

Can You Share Code Between Files? If So, Then How?

Reference answer

Sharing code between files can expedite your development process. Here are some tools you can do that: - Bit - NPM libraries - Multi-package repositories Read more about sharing code between files.

131

Describe your favorite project on which you've worked.

Reference answer

"One of my favorite projects was developing a real-time data dashboard for a logistics company. I led the front-end development using React and integrated it with a Node.js back-end. The biggest challenge was optimizing the data flow to ensure real-time updates without performance issues. I implemented web sockets and data caching strategies, which significantly improved the dashboard's responsiveness."

132

How do you stay updated with the latest industry trends and technologies in web development?

Reference answer

I follow industry blogs like Smashing Magazine and CSS-Tricks, attend webinars and conferences, participate in online communities like GitHub and Stack Overflow, and experiment with new frameworks or tools in side projects. I also take courses on platforms like Udemy and Coursera.

133

How can the style/class of an element be changed?

Reference answer

To change the style/class of an element there are two possible ways. We use document.getElementByID method document.getElementById("myText").style.fontSize = "16px; document.getElementById("myText").className = "class";

134

What Is Pair Programming?

Reference answer

Pair programming is a relatively new software development technique. The practice involves two programmers assuming roles known as driver and navigator. The driver is the person writing the code while the navigator observes each line for correctness. There are a few different ways that programmers are paired during a pair programming sprint. That includes: - Expert-expert: Usually done on more complex projects where two experts can work together to boost each other's productivity. - Beginner-beginner: Programmers who are early in their career might not be able to handle projects on their own and are therefore paired with someone with whom they can bounce ideas and write code. - Expert-newbie: This pairing is done so that the younger programmers in the team can spend time observing and learning from the more experienced developers.

135

What skills should a Full Stack developer have?

Reference answer

A Full Stack developer should be familiar with: - Basic languages – Must be proficient in basic languages like HTML, CSS, and SQL. - Front-end frameworks – BootStrap, AngularJS, VueJS, ReactJS, JavaScript, TypeScript, Python, Ruby, PHP. - Back-end frameworks – Express, Django, NodeJS, Ruby on Rails. - Databases – MySQL, SQLite, Postgres, MongoDB, Cassandra, Apache storm, Sphinx. - Additional skills recommended – Git, Machine Learning, SSH, Linux Command, Data Structures, Character encoding.

136

What is Node.js, and why is it commonly used in back end development?

Reference answer

Node.js is a JavaScript runtime built on Chrome's V8 engine, enabling server-side execution. It is popular for back end development due to its non-blocking, event-driven architecture, which handles high concurrency efficiently, and its large ecosystem via npm for libraries.

137

Describe how you would secure an API using authentication and authorization techniques

Reference answer

Rather than overlapping each other, authorization and authentication reference two very distinct stages of security within your app. On one side, we have authentication, in charge of verifying the user identity. You can use tokens (e.g., JWT, OAuth) or sessions for this. Example: Validate a JWT sent in headers: Once authenticated, users need to be authorized to access the resources. For this to work, you'll need to define roles and permissions for your users. Middleware example: Use HTTPS to ensure a secure channel between the browser and the server. Validate input to prevent injection attacks. Rate-limit API requests to avoid having your APIs overwhelmed by potential attackers. Store sensitive data securely (e.g., hashed passwords).

138

What is CI (Continuous Integration)? What is continuous integration and continuous delivery (CI/CD)?

Reference answer

CI is nothing but an abbreviation for Continuous integration. It is a computer program development practice in which frequent and disconnected changes are immediately tested, and reported to the codebase. This helps the developer to identify issues at the earlier stage of development, makes it easier to fix bugs, and curtails problems at the merge for the release.

139

What is the difference between acceptance and functional testing?

Reference answer

Functional testing is a process of verification of whether the processes in the applications are running according to business requirements. Acceptance testing, on the other hand, is the process of assessing the app against a customer's needs. This type of testing helps business owners find out whether end-users enjoy interacting with the application.

140

What is @RestController in Spring Boot?

Reference answer

Annotation in Spring Boot that combines @Controller and @ResponseBody. It marks a class as a REST API controller.

141

What is Superuser?

Reference answer

superuser is the most powerful user with permission to create, read, delete, and update on the admin page which includes model records and another user. Users of Django have access to an Admin Panel. Before using this feature, you must have to migrate your project; otherwise, the superuser database will not be created. To create a superuser, first, reach the same directory, and run the following command python manage.py createsuperuser

142

Can you collaborate on a team?

Reference answer

Pair programming is a collaborative system or technique where one person writes code while the other observes to ensure the code is written correctly. This allows you to identify bugs sooner, and developers can share knowledge to write better code. Pair programming can be especially useful for working with new hires. Your interviewer wants to know how you work on a team with other programmers and if you have experience collaborating while programming. You may want to give an example of when you have collaborated using pair programming and what you learned from collaborating on that team.

143

Write a SQL query to select students with marks greater than 60.

Reference answer

SELECT * FROM students WHERE marks > 60;

144

How do you stay updated with the latest web technologies?

Reference answer

Share your learning strategies! Talk about the tech blogs you follow, the Discord communities you are part of, or the side projects you work on to experiment with new tools.

145

Can you provide an example of a challenging project or problem you worked on as part of a team and how you contributed to its resolution?

Reference answer

In a previous project, we faced performance issues with a database-driven application under high traffic. I collaborated with the team to identify bottlenecks, optimised queries with indexing, implemented caching with Redis, and refactored the code to reduce load. This improved response times by 40% and ensured scalability.

146

What is normalization in databases?

Reference answer

Process of reducing redundancy and ensuring data integrity in database tables.

147

How would you handle asynchronous operations in a Node.js application?

Reference answer

I handle asynchronous operations using callbacks, Promises, or async/await. For example, with async/await: `const data = await fetchData();` ensures readability. Promises chain operations, and callbacks handle older APIs. I avoid callback hell by using modern patterns and libraries like `async.js`.

148

How do you differentiate between 'fast-forward' and 'no-fast-forward' merges, and in which situations would you use each?

Reference answer

This question looks for the candidate's grasp of merging strategies, knowledge of how they impact the git history, and the ability to discuss the implications of each approach.

149

What is thread contention?

Reference answer

Contention is simply when two threads try to access either the same resource or related resources in such a way that at least one of the contending threads runs more slowly than it would if the other thread(s) were not running. Contention occurs when multiple threads try to acquire a lock at the same time

150

Where Do You See Yourself in Five Years?

Reference answer

To answer this question, clarify your goals. So take some time to think about your career, what you want to achieve, and what new experiences you want to have professionally. Once you've done that, you can create parallels between the job description and your career goals. For example, let's say you want to improve as a front-end developer. A job that mentions skills in HTML, CSS, and Javascript is a good fit for this.

151

Which is faster in JavaScript and ASP script?

Reference answer

JavaScript is faster compared to ASP Script. JavaScript is a client-side scripting language and does not depend on the server to execute. The ASP script is a server-side scripting language always dependable on the server.

152

What are some strategies for improving the SEO of a React-based application?

Reference answer

Server-Side Rendering (SSR): Use frameworks like Next.js to render pages on the server for better crawlability. Meta Tags: Dynamically set titles, descriptions, and keywords using libraries like react-helmet. Sitemap and Robots.txt: Generate a sitemap.xml and configure robots.txt for search engines. Lazy Loading: Ensure above-the-fold content loads quickly. Structured Data: Add JSON-LD for rich search results. Canonical URLs: Avoid duplicate content issues with proper canonical tags.

153

Tell me about a time you had to learn a new technology quickly to finish a project.

Reference answer

We were mid-sprint when our team decided to migrate from a REST backend to a GraphQL layer, mostly to support a new mobile client. I'd done very little with GraphQL at that point. The challenge was that we had about two weeks before the mobile team was blocked. I blocked off the first two days to go deep on Apollo Server and the schema-first approach, built a small proof of concept with our existing data models, and had my first resolvers reviewed by a senior engineer by the end of that week. We shipped the migration on time, and it actually went smoother than expected because of the upfront investment in learning the schema design properly. After that project, I became the de facto person on the team for GraphQL questions.

154

Is it possible to break JavaScript Code into several lines?

Reference answer

Yes, it is possible to break the JavaScript code into several lines in a string statement. It can be broken by using the '\n' (backslash n). For example console.log("A Online Computer Science Portal\n for Geeks") The code-breaking line is avoid by JavaScript which is not preferable. let gfg= 10, GFG = 5, Geeks = gfg + GFG;

155

What is called Variable typing in JavaScript?

Reference answer

The variable typing is the type of variable used to store a number and use that same variable to assign a "string". Geeks = 42; Geeks = "GeeksforGeeks";

156

Explain the difference between front-end and back-end development.

Reference answer

Front-end is all about what clients see from the front and interact with the UI, like buttons and menus. The back-end is about making sure everything works easily behind the scenes, such as Backend languages like Java, C#, and Python.

157

What are some of the benefits of using TypeScript over plain old JavaScript?

Reference answer

TypeScript adds static typing, which makes code readable, reduces bugs, enhances code editor support—like IntelliSense—and sets the ground for better refactoring and documentation of your code. Modern JavaScript features, including compatibility, are also included.

158

What is the difference between thread and process?

Reference answer

Threads (of the same process) run in a shared memory space, while processes run in separate memory spaces

159

What are React and Angular?

Reference answer

Frontend frameworks for building dynamic, single-page applications (SPAs).

160

Describe a challenge you faced with a project and how you resolved it.

Reference answer

Be honest here! Talk about a real challenge from your projects – maybe a particularly tricky bug or a feature that seemed impossible at first. Explain how you approached the problem and what you learned from it.

161

What Are Your Weaknesses?

Reference answer

First, talk about your weaknesses honestly. Here are a few things that might pop into your head: - Taking on too many responsibilities - Impatience in wanting to see a project through - Getting nervous interacting with large groups of people - Not knowing a specific programming language - Feeling hesitant delegating tasks to other team members Remember, you want to talk about these things without getting too negative. Let recruiters know how you identified this weakness, and what you're doing to address it. Here are some sample answers: “I realized at my first job that I have a hard time approaching other team members for help. I would take on a large amount of work because I was excited to contribute to the team. But I would run into issues and wouldn't admit that I needed to consult more experienced team members to solve those problems. I decided to talk to one of my managers about this. She let me know that the company encouraged younger developers to seek help from the more experienced ones and that everyone on the team enjoyed lending a helping hand. That put me at ease and I slowly began to turn to my colleagues for help when I needed it.”

162

What is system design, and why is it important?

Reference answer

System design is the process of defining the architecture, components, and data flow of a software system to meet specific requirements. It ensures scalability, reliability, and maintainability by outlining how different modules interact. Good system design prevents bottlenecks, optimizes performance, and facilitates future enhancements.

163

What qualities do you think a Full Stack Developer must have?

Reference answer

This question is pretty much straightforward in itself and particularly crucial for freshers. While listing the skills, make sure to include the following: Front-end technology Development languages Database and cache Basic designing skills Server skills Ability to work with APIs Ability to work with Version Control System (VCS)

164

Tell Us About Your Favorite Project. What Did You Learn?

Reference answer

Since you're a junior developer, you probably don't have too many work projects to talk about. So it's fair to mention any of your own personal projects. Describe the goals of the project and the programming languages and tools you used to achieve them.

165

How do you leverage Content Delivery Networks (CDNs) and caching mechanisms to enhance website performance?

Reference answer

I use CDNs like Cloudflare or AWS CloudFront to cache static assets (e.g., images, CSS, JavaScript) at edge locations, reducing latency. For dynamic content, I implement browser caching with Cache-Control headers, and server-side caching with Redis or Varnish for API responses, ensuring faster load times.

166

What coding have you completed outside of work?

Reference answer

"Outside of work, I've been contributing to an open-source project that focuses on building a machine learning library for web applications. I've also completed several online courses on advanced JavaScript and Node.js. These activities have not only improved my coding skills but also allowed me to stay updated with the latest technologies and best practices."

167

What are the benefits of using containerization in application deployment?

Reference answer

Containerization involves encapsulating an application and its dependencies into a container that can run consistently across various environments. Benefits include: - Consistency: Ensures the application runs the same way in development, testing, and production environments. - Isolation: Containers isolate applications from each other, enhancing security and stability. - Scalability: Containers can be easily scaled horizontally to handle increased load. - Resource Efficiency: Containers share the host OS kernel, making them more lightweight compared to virtual machines.

168

Explain server-side rendering.

Reference answer

Server-side rendering generates the full page HTML on the server in response to navigation, beneficial for SEO and initial page load times.

169

Discuss an example where you had to refactor a codebase as part of the solution to a problem. What was your approach and what challenges did you face?

Reference answer

Candidates need to show a deep understanding of the code architecture and the reasons behind refactoring, as well as the ability to improve code maintainability and performance without breaking existing functionalities.

170

What is middleware in terms of backend development?

Reference answer

Middleware is software that sits between the application server and the database (or other services). It processes requests, responses, and performs actions like authentication, logging, etc.

171

What HTML topics are included in the interview questions?

Reference answer

This part covers key HTML topics, including essential tags, the role of meta tags, semantic HTML, and attributes like async, defer, and sync. We also discuss accessibility, SEO optimization, and best practices for writing clean and organized HTML.

172

Tell me about yourself (Sample HR answer).

Reference answer

“I love solving problems end-to-end - from database to UI. Java gives me backend power, and learning frontend helps me visualize what users experience. I enjoy working on complete solutions, not just one layer.”

173

Explain a Few Pros and Cons of Using “Use Strict”

Reference answer

You might not be familiar with Use Strict as a budding full-stack developer. However, the interviewer might ask you to discover if you've dug deeper into the field or are only focusing on surface-level knowledge. “Use strict offers several benefits. For instance, it detects common coding mistakes by throwing errors, disables confusing features, and gives an error in the event of unsafe actions. However, there's no rose without a thorn. The feature also has a few downsides. For instance, developers may encounter issues when concatenating scripts in various strict modes. Besides, two primary features, function.arguments and function.caller, are no longer accessible.”

174

What Are the Differences Between Server-Side Scripting and Client-Side Scripting?

Reference answer

Here are the differences between server-side scripting and client-side scripting: - Server-side scripting involves writing the code that will work in the backend and not be seen by the users of the applications. Client-side scripting is the writing of code that will influence what users see. - Server-side scripting requires interactions with the server being used for an application. The client-side description doesn't involve interactions with the server. - Server-side scripting is used to improve how server resources are used. Client-side scripting can improve user experiences and the aesthetic appearance of applications. - HTML, CSS, and Javascript are common client-side scripting languages. ASP.NET, Java, and PHP are common server-side scripting languages.

175

What is API rate limiting, and why is it important?

Reference answer

API rate limiting is the process of restricting the number of requests a user can make to an API in a given time period. It helps prevent abuse of the API, ensures fair usage, and protects servers from being overwhelmed. Common Strategies: - Token Bucket Algorithm (limits requests based on available tokens). - Leaky Bucket Algorithm (processes requests at a fixed rate). - Fixed Window and Sliding Window Log algorithms (track request counts over time). Rate limiting prevents DDoS attacks, ensures fair resource usage, and improves API stability.

176

What's the Difference Between “Resetting” and “Normalizing” CSS?

Reference answer

Resetting removes all of the default stylings that browsers apply to the elements on a page. Normalizing doesn't remove all of the defaults; it maintains the more useful ones. Read more about resetting and normalizing.

177

What Are the Functions of HTML, CSS, and JavaScript?

Reference answer

HTML - Helps to organize information CSS - Styles the content JavaScript - Allows users to interact with the site and makes the site dynamic Them these three is the basis of all web development.

178

What are the differences between var, let, and const in JavaScript?

Reference answer

- var: Function-scoped and can be redeclared. It also has hoisting behavior, meaning it's accessible even before its declaration. - let: Block-scoped and cannot be redeclared within the same scope. It is preferred for modern JavaScript to avoid issues with var. - const: Block-scoped and cannot be reassigned after declaration. It's used for values that should not change, such as constants.

179

How can we animate using CSS?

Reference answer

CSS Animations is a technique to change the appearance and behavior of various elements in web pages. It is used to control the elements by changing their motions or display. It has two parts, one which contains the CSS properties which describe the animation of the elements and the other contains certain keyframes which indicate the animation properties of the element and the specific time intervals at which those have to occur. The @keyframes rule: Keyframes are the foundations with the help of which CSS Animations works. They define the display of the animation at the respective stages of its whole duration. For example: In the following code, the paragraph changes its color with time. At 0% completion, it is red, at 50% completion it is of orange color and at full completion i.e. at 100%, it is brown. Example

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180

Do You Prefer To Work on Your Own, or as Part of a Team?

Reference answer

You can start by listing the advantages and disadvantages of working independently and in a team environment. This shows that you understand both of these modalities well. Then, honestly share your preference. Explain why that's your preference. Maybe you prefer working in a team because interacting with others energizes you. Or perhaps you prefer working alone because it helps you focus. Before answering, consider whether the job description mentions that candidates need to be able to work in a particular way.

181

What is the purpose of HTML, CSS, and JavaScript in web development?

Reference answer

HTML: Defines the structure and content of a webpage. CSS: Styles the webpage (colors, layout, fonts). JavaScript: Adds interactivity and dynamic behavior to the webpage.

182

What are React hooks, and why are they used?

Reference answer

React hooks are functions that let you use state and other React features in functional components. With hooks you can simplify state and lifecycle management without needing class components. They also enable code reuse through custom hooks. Examples of different hooks: useState for managing state. useEffect for handling side effects (e.g., fetching data). useContext for global state.

183

How to handle environment variables in Node.js?

Reference answer

We use process.env to handle environment variables in Node.js. We can specify environment configurations as well as keys in the .env file. To access the variable in the application, we use the "process.env.VARIABLE_NAME" syntax. To use it we have to install the dotenv package using the below command: npm install dotenv

184

What are environment variables, and how are they used?

Reference answer

Environment variables store configuration values (e.g., API keys, database URLs) outside the codebase. This is important for two main reasons: Security. By extracting these values (which tend to be private) from the codebase, you avoid potential code leaks from becoming a bigger security problem. More flexible deployments. If these values need to change, by having them as environment variables you don't need to re-deploy your code, you just need to reload those values (either by restarting the app, or hot reloading the values from a file). For the actual implementation, one might use something like the dotenv module, which loads environment variables from a .env file in the local folder of the project, or interact with a secret manager, such as AWS Secret Manager which stores these values externally in a secure storage.

185

What are PWAs and how do they help full-stack developers?

Reference answer

This is among the most popular full stack interview questions and answers. Progressive Web Apps use contemporary web technologies to give consumers a native app-like experience. Users may install and utilize them from their home screens without needing an app store because they blend the greatest elements of online and mobile applications. Benefits of PWAs in full-stack development: - Cross-platform compatibility: PWAs work across multiple platforms and devices, eliminating the need for separate development efforts for different platforms. - Offline capabilities: PWAs can function offline or with a poor internet connection, providing a seamless user experience even in challenging network conditions.

186

Explain any project you worked on using Full Stack Java.

Reference answer

“I developed a Student Management System using Spring Boot (backend), React (frontend), and MySQL (database). Frontend built with React fetches data via REST API. Backend uses Spring Boot + JPA for CRUD operations. Authentication handled using JWT. Deployed via Docker on AWS EC2. It helped me understand the entire development lifecycle from coding to deployment.”

187

Can you discuss your experience working in Agile environments?

Reference answer

Team projects are perfect examples here. Talk about your experience with daily standups, sprint planning, and project demos. Why This Matters Most development teams use Agile methodologies, and showing you are familiar with them is a big plus.

188

What is event bubbling and capturing?

Reference answer

target.addEventListener(type, listener[, useCapture])

189

What is the DOM?

Reference answer

The Document Object Model (DOM) is the browser's structured representation of a webpage. JavaScript interacts with the DOM to: - Insert or remove elements - Alter content - Modify styles - React to user inputs This enables dynamic, interactive user experiences.

190

What is a design pattern?

Reference answer

A design pattern is a reproducible or reusable solution for frequent problems in software design. Such patterns show the relationships and interactions between classes and objects. There are three main types of design patterns: - Creational: Related to class instantiation and object creation. These are further categorized into class-creational patterns and object-creational patterns. - Structural: Related to the organization of different classes and objects to provide new and more extensive functionality. - Behavioral: Concerned with identifying common communication patterns between objects.

191

What is JWT?

Reference answer

JSON Web Token - used for authentication between client and server.

192

What is the event bubbling and capturing in JavaScript?

Reference answer

Event bubbling is when an event triggered on a nested element propagates up through its ancestors in the DOM tree. Event capturing (or trickling) is the opposite, where the event is first captured by the outermost element and then propagates down to the target. Both are phases of event propagation.

193

How do you use Postman for testing APIs?

Reference answer

Create a Request: Enter the API endpoint, method (GET, POST, etc.), and headers. Send Data: Add query params, body (JSON, form data), or headers. Send Request: Click "Send" to view the response. Assertions: Use the Tests tab to write scripts (JavaScript) for automated validation of responses. Example: Collections: Group requests for testing workflows or environments.

194

Can You Share an Experience When You Found Your Colleagues' Code To Be Inefficient? How Did You Deal With It?

Reference answer

Start by describing a situation where you found that there was code that could have been written better or optimized. Then, explain how addressed the issue with your colleague. Clarify that you didn't throw your colleague under the bus for their mistake, but that you instead raised the issue in a respectful manner.

195

What is Promise and explain its states?

Reference answer

Callback functions are functions that can be passed to another function as arguments and executed there to complete a routine or action. Those functions depend on one another, so it could get quite messy with so many callback functions nested in so many layers. This is what is referred to as callback hell. As an alternative to callbacks in JavaScript, promises are used to handle asynchronous operations. In addition to handling multiple asynchronous operations, they provide better error handling than callbacks. Promises can be a better way for a user to read the code effectively and efficiently, especially when that particular code performs multiple asynchronous operations. The Promise object represents the result of an asynchronous operation (or its failure) and the resulting value. The promise is in one of the following states: - Pending: In its initial state, neither fulfilled nor rejected. - Fulfilled: Indicating that the operation was successful. - Rejected: Indicating that the operation failed.

196

Name some databases that integrate with Express JS?

Reference answer

Express.js can support a variety of the databases which includes: - MySQL - MongoDB - PostgreSQL - SQLite - Oracle

197

Can you give an example of how you have contributed to a positive team environment?

Reference answer

Think about your experiences working in teams at CodeBoxx. Maybe you helped a struggling classmate or took the lead on organizing team meetings?

198

What is numeric promotion?

Reference answer

The conversion of a smaller numeric type to a larger numeric type is known as numeric promotion. In this type, byte, char, and short values are converted to int values. The int values are converted to long values, if necessary. The long and float values are converted to double values, as needed.

199

How do you stay up-to-date in your field?

Reference answer

Regularly reading tech blogs, attending developer conferences, participating in online courses, and staying active in GitHub and Stack Overflow communities.

200

What's the Difference Between Normalization and Denormalization?

Reference answer

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