Full Stack Developer Interview Questions

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Last Updated: 05 Jul 2023

After completing your Full Stack Developer Course are you ready to excel in your interview? You're in the right place! With our insightful guide on Full Stack Interview Questions and Answers, you are setting the stage for success. 

Hundreds of candidates have triumphed in their interviews, all thanks to the diligent preparation they undertook with these questions. 

Handpicked by industry experts, these are the most probable questions you'll face during your interview. 

The aim is not merely to equip you with answers, but to foster a deeper understanding of Full Stack Development, ensuring you're ready for every possible question.

By investing your time in these Full Stack Interview Questions and Answers, you're not just preparing for an interview - you're laying the foundation for your burgeoning career in Full Stack Development. 

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Most Common Full Stack Interview Questions and Answers

What Is Full Stack Development?

  • Full Stack Development refers to the process of developing both the front end (client side) and the back end (server side) of a web application.
  • This involves a comprehensive understanding of the various stages of a web application, including UI/UX, middleware, backend programming, databases, version control, and possibly more.

What Do Full Stack Web Developers Do?

Full Stack Web Developers are involved in every phase of a web application. They are jacks of all trades in the coding world. Their responsibilities include:

  • Designing user interactions on web pages.
  • Developing servers and databases for website functionality.
  • Ensuring cross-platform optimization for mobile devices.
  • Seeing out a project from conception to final product.
  • Designing and developing APIs.

What Skills Do You Need to Be a Full-Stack Developer?

Becoming a Full-Stack Developer requires a multitude of skills, including but not limited to:

  • Frontend Skills: Proficiency in HTML/CSS, JavaScript, and libraries or frameworks such as React, Angular, or Vue.js.
  • Backend Skills: Familiarity with server-side languages like Python, Ruby, Java, or .NET, and understanding of server-side frameworks like Express.js, Django, or Ruby on Rails. There are courses for Python Training in Ahmedabad, Django training and all types of languages! Enroll in one to master the language you want to excel at.
  • Databases: Knowledge of various DBMS technologies like MySQL, MongoDB, Oracle, SQLServer, etc.
  • Version Control/Git: Understanding of Git, GitHub, and version control methods.
  • Basic Design Ability: Knowledge of basic prototyping and UX/UI design.
  • Understanding of REST and HTTP Protocol.
  • Web Architecture: Ability to structure the code, separate the file, structure the data in databases, and perform complex server-client builds.

What Distinguishes The Terms Abstract And Interface?

Abstract Class
  • It is a type of class in object-oriented programming.
  • It is declared using the keyword 'abstract.'
  • It can have methods with implementations.
  • It can have both abstract and non-abstract methods.
  • It can contain constructors, variables, and blocks.
  • It cannot be instantiated.
  • It's a blueprint of a class in object-oriented programming.
  • Declared using the keyword 'interface.'
  • Cannot have methods with implementations (until Java 8 introduced default and static methods).
  • It can have only abstract methods.
  • It cannot contain constructors, variables, or blocks.
  • It cannot be instantiated.


Abstract Class


What is it?

A type of class in OOP.

A blueprint of a class in OOP.


Declared using 'abstract'.

Declared using 'interface'.


Can have both abstract and non-abstract methods.

Traditionally only abstract methods (until Java 8).

Other elements

Can contain constructors, variables, and blocks.

Cannot contain constructors, variables, or blocks.


Cannot be instantiated.

Cannot be instantiated.

What is Pair Programming? Explain.

  • Pair Programming involves two programmers sharing a single workstation (one screen, keyboard, and mouse among the pair).
  • The programmer who writes the code is called the "Driver," while the other, reviewing each line of code as it's typed in, is the "Navigator."
  • The "Navigator" thinks about the big picture, spots errors, and thinks ahead.
  • The two programmers switch roles often.
  • It encourages teamwork, improves code quality, and promotes knowledge sharing.

Pair Programming Example

Let's consider a simple JavaScript function that calculates the sum of all numbers in an array. Here's how the process might look during pair programming.

Navigator's Suggestions

  1. Suggest using a higher-order function like reduce instead of a for loop for code conciseness.
  2. Check if the input is indeed an array and if it is empty.
  3. Handle cases where the array includes non-numeric values.
Revised Code After Pair Programming

In the revised code, the Navigator helped the Driver enhance the function by using the reduce method, checking for input validity, and handling potential exceptions.

What Is CORS?

  • CORS stands for Cross-Origin Resource Sharing.
  • It is a mechanism that uses additional HTTP headers to tell browsers to give a web application running at one origin access to selected resources from a different origin.
  • CORS mechanisms work by adding specific HTTP headers that tell the browser to allow web applications from one origin to access the resources at a different origin.

What Is Inversion of Control (IoC)?

  • IoC is a principle in software engineering where the flow of a program is inverted. Instead of the programmer controlling the flow of a program, the external framework or runtime controls it.
  • IoC is a key part of many frameworks, enabling better modularity, more straightforward testing, and higher flexibility.
  • Dependency Injection is a form of IoC where implementations are passed into an object through constructors/setters/service lookups, which removes the dependency of the object to instantiate or find the particular service.

What Is Continuous Integration?

  • Continuous Integration (CI) is a software development practice in which small adjustments to the underlying code base are continuously applied and tested in a shared repository.
  • The goal of CI is to catch and address bugs quicker, improve software quality, and reduce validation and release time.
  • Developers often use a version control system such as Git and automation servers like Jenkins, Travis CI, and CircleCI for CI.
  • This practice is often part of a larger cultural approach known as DevOps, which brings together software development and IT operations.

How Is GraphQL Different from REST?




Data Fetching

Allows fetching exactly what you need, no more, no less. Avoids over-fetching and under-fetching.

You have to download the entire representation of a resource, which can lead to over-fetching/under-fetching.


Avoids versioning as new fields can be added to server responses without impacting existing queries.

Often requires versioning (v1, v2, etc.) when the structure of resources changes over time.


Due to precise fetching, it can be faster, especially over slow network connections.

Can be slower due to over-fetching of data and more round trips.

Error Handling

Returns a 200 OK status even when an error occurs during the processing of a request. Errors are included in the response body.

Uses HTTP status codes to indicate the nature of the error (4xx for client errors, 5xx for server errors, etc.).

What Is the Observer Pattern?

The Observer Pattern is a design pattern that establishes a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically. This is commonly used in event handling systems. Here is a simple implementation of the Observer Pattern in JavaScript:

What Is the Recommended Way to Check If a Resource Exists in RESTful APIs?

The recommended way to check if a resource exists in RESTful APIs is by using the HTTP method HEAD. It retrieves headers for a resource, without fetching the body, thus making it a lightweight method for checking if a resource exists.

How Can Database Table Design Be Improved for Better Data Management?

  • Normalization: It eliminates redundant data, which can improve the integrity and performance of the database.
  • Use of Indexes: They can significantly improve the performance of data retrieval operations.
  • Consistent Naming Conventions: They help to keep things clear and understandable for all developers.
  • Use of Foreign Keys: They enforce referential integrity in the database.
  • Appropriate Use of Data Types: It ensures data consistency and can also optimize storage.

How Can You Avoid Making the User Wait for Longer When Integrating Third-Party Services Within Your API Requests?

  1. Asynchronous Operations: You can use asynchronous operations so the user's experience is not blocked by a third-party API request.
  2. Caching: Store frequently used data from third-party APIs locally to reduce the need for future requests.
  3. Fallback Mechanisms: Have a contingency plan to maintain functionality even if the third-party service is slow or unresponsive.

What HTTP Status Code Should You Return When a User Attempts to Create a Resource That Already Exists?

When a user attempts to create a resource that already exists, the appropriate HTTP status code to return would be 409 Conflict. This indicates that the request could not be completed due to a conflict with the current state of the resource.

How Would You Prevent a Bot from Scraping Your Publicly Accessible API?

  1. Rate Limiting: Limit how often an individual user/IP address can make requests in a certain period.
  2. User Authentication: Implement some form of user authentication to ensure only authorized users access your API.
  3. CAPTCHA: Require users to solve CAPTCHA to confirm they're human.
  4. Analyze Traffic: Regularly monitor and analyze your API traffic for patterns that resemble bot activity.

Write a Query to Retrieve All Data from a Specific Table and Include a Count of Related Data from Another Table.

Here's a sample SQL query using a LEFT JOIN and GROUP BY to achieve this. In this example, we're retrieving all data from a Users table and a count of related Orders from an Orders table.

This will return all Users along with a count of their related Orders.

How Do You Ensure a Full-Width Image in a Responsive Site Design Loads the Smallest Image Required to Fill the Space?

To achieve this, you can use the srcset attribute on the img tag in HTML5. This allows the browser to choose the most suitable image based on the current viewport size. You can learn about more interesting attributes in HTML by enrolling in an HTML Training Course. Here's an example:

Using CSS, How Do You Ensure a Box Is Horizontally and Vertically Centered?

You can use CSS Flexbox or CSS Grid to center a box both horizontally and vertically. Taking a CSS Training Course can help you learn everything you need to know about such attributes and more! Here's a sample using Flexbox:

In this example, any direct child of the “.container” will be centered both vertically and horizontally within the container.

What Are Key Considerations When Coding with SEO in Mind?



Semantic HTML

Helps search engines understand the content and structure of your website.

Meta Tags

Provides information to search engines about your web pages, such as the title, description, and keywords.

Alt Text for Images

Helps search engines understand what the images are about and improves accessibility.

URL Structure

A clear, concise, and relevant URL structure helps search engines and users understand what a page is about.

Page Speed

Optimizing code for faster page loads can improve SEO, as page speed is a ranking factor.

Mobile Responsiveness

Google uses mobile-first indexing, so ensure your website is fully responsive and optimized for mobile users.

Use of robots.txt and sitemap.xml

These files help search engines understand which pages to crawl and index.

What's the Difference Between a Full Stack Engineer and a Full Stack Developer?

Full Stack Developer

Full Stack Engineer


A programmer competent in multiple languages and frameworks. They can handle all work related to databases, servers, system engineering, and clients.

Similar to a Full Stack Developer, but with a more focused emphasis on engineering concepts like system design and scalable system architecture.


May include: coding, debugging, testing, web design, integrating applications, and database management.

In addition to tasks performed by a Full Stack Developer, a Full Stack Engineer might also handle project management and leading a development team.


Expertise in front-end and back-end languages, databases, UI/UX design.

In addition to Full Stack Developer skills, Full Stack Engineers often require a deeper understanding of system architecture and problem-solving skills.

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Having a solid foundation in Full Stack Development and being prepared with the most probable interview questions is crucial in achieving your career goals. However, the real edge comes from having a thorough and practical understanding of Full Stack Development. That's why enrolling in a comprehensive Full Stack Developer Course is pivotal.

TOPS Technologies in Ahmedabad is a reputed IT training and placement institute, renowned for their Full Stack Developer Course. With an impressive track record of successful placements and industry recognition, TOPS Technologies offers an affordable yet comprehensive curriculum. 

So, why wait? Enroll today to secure a high-paying job in the field of Full Stack Development. Your journey to success starts at TOPS Technologies.

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