12 Most Popular Full Stack Developer Interview Questions and Answers

Full Stack Developers are professional programmers who are responsible for coding both the front and back ends of websites and applications. They develop and design front end/back end web architecture, server-side applications, handle databases, create web design features, and much more.

The job profile of a Full Stack Developer has gained increasing importance in the past few years, thereby boosting their career scope and employment opportunities. Since Full Stack Developers are well-versed with all layers of an application and have the flexibility to work with different technologies, they can create interactive and intuitive apps for companies. Furthermore, they are skilled in solving various technical glitches across the different stages of app development. This is why companies are now creating high demand for Full Stack Developers and conducting interviews for the same. Doing full stack development courses increases your chance to get your dream job. Let’s explore some of the most common full stack developer interview questions and answers! The most frequently asked java full stack developer interview questions are included for a comprehensive understanding.

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If you too are rooting to crack your next Full Stack Developer interview, here’s a list of questions you would definitely like to know!

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Full Stack Interview Questions and Answers

1. What is Pair-Programming? 

Pair Programming refers to one of the fundamental aspects of extreme programming wherein two Developers work on the same terminal. The Developer responsible for writing the code is the “driver,” whereas the Developer who reviews the code is called the “navigator.”

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  2. What is CORS?

CORS stands for Cross-Origin Resource Sharing. It is a technique used for accessing web resources on diverse domains. CORS allows you to seamlessly integrate web scripts with the external content of the primary domain, thereby facilitating better web service integration.

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3. What is the purpose of the Bridge Pattern?

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.

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4. Mention the success factors for continuous integration.

The success factors required for continuous integration include:

Maintaining a code repository.
Automating the build.
Incorporating self-testing feature into the build.
Designing the build to be fast.
Testing the build in a clone production environment.
Making the deliverables accessible to team members.
Making the results accessible and visible to team members.
Automating the deployment process.

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5. What is the core difference between REST and GraphQL?

The most fundamental difference between REST and GraphQL is that in the REST model, the type/shape of the resource and the way of retrieving that resource is coupled, whereas in GraphQL these two concepts are completely independent of each other. Basically, the core difference between the two is that in GraphQL, the description of a particular resource is not coupled to the way of retrieving it, unlike REST.

6. Name a few ways in which you could optimize a website to enhance its scalability and efficiency.

A Full Stack Developer can optimize a website in the by:

Reducing DNS lookups.
Avoiding URL redirects.
Avoiding duplicate codes.
Avoiding unnecessary images.
Leveraging browser caching.
Deferring parsing of JavaScript.
Avoiding inline JavaScript and CSS.
Using “srcset” for responsive images.
Placing all assets on a cookie-free domain, preferably using a CDN.

7. Usually, while integrating third-party services in your API requests often leads to long response times. 

How can you avoid this? Do you know any technologies relevant to solving this issue?

The most efficient way to solve this issue is to use queues. So, when a request is made to your API, a separate job will be created and added to a queue. This job will be executed independently to the requested endpoint, thereby allowing the server to respond without any delay.

Some of the best queue providers are Redis, Beanstalkd, and Amazon SQS.

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8. How can you prevent a bot from scraping a publicly accessible API?

Considering that the data in the API is publicly accessible, it is not possible to prevent data scraping completely, at least technically. However, there is one solution that can deter both bots and humans. It is called Rate Limiting, also known as Throttling.

Throttling helps to prevent a particular device from making a defined number of requests within a stipulated time, upon exceeding which it will show the following HTTP error:

“429 Too Many Attempts”

While this is an effective method to prevent bots from scraping a publicly accessible API, you must track the device in question with more than just the IP address since it is not unique to the device, and hence, it may cause an entire network to lose access to the API.

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Full Stack Interview Questions to which you must devise impromptu but well-thought-of answers:

9. What’s your favorite language, and why?

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.

  10. How do you keep yourself updated with the latest trends and developments in the industry?

This question is aimed at finding out whether or not a candidate is actively involved in the technology and developer community.

When you answer this question, make sure to mention about your involvement in community meetups, tech conferences, etc. Also, you can mention the names of the webinars, forums, and seminars you frequently visit. If you have personal projects under your wing, don’t hesitate to talk about them as well.

  11. Tell me something about your recent learnings.

This question usually follows the previous question to test the authenticity of your claims. While answering this question, you must be able to talk in detail about the latest industry trends, technological innovations, and new methodologies. In this fast-changing industry, it is essential for professionals to upskill and keep themselves updated about the latest industry trends.

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

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)

13. Describe the concept of microservices architecture and its benefits.

An architectural design known as microservices architecture organizes an application as a group of compact, loosely linked services. Each service performs a distinct function and interacts with other services via lightweight protocols like HTTP or message systems. This method can make large-scale applications scalable, flexible, and maintainable.

Advantages of microservices architecture include:

• Scalability: Microservices allow individual services to scale independently, which helps handle varying loads on different application components.
• Flexibility: Developers can choose different technologies and frameworks for each microservice, enabling them to select the most suitable tool for each task.
• Maintainability: With smaller, focused services, it becomes easier to understand, modify, and test each component, leading to better maintainability of the overall system.

14. Describe containerization and why it’s important for full-stack development.

Applications and their dependencies can operate in different environments called containers thanks to the lightweight virtualization approach known as containerization. Regardless of the underlying infrastructure, each container isolates the application and its dependencies to offer a consistent and repeatable environment.

Significance of containerization in full stack development:

• Reproducibility: Containers encapsulate the application’s runtime environment, including libraries, dependencies, and configurations. This ensures that the application runs consistently across different environments.
• DevOps integration: Containerization aligns well with DevOps principles, allowing developers and operations teams to work together seamlessly. Containers can be easily integrated into continuous integration/continuous deployment (CI/CD) pipelines, enabling faster and more reliable application delivery.

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

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.

16. What are the key considerations when designing a database schema for a full-stack application?

The key considerations are:

• Data normalization: Ensuring that the database schema follows normalization principles helps eliminate data redundancy and improves data integrity.
• Scalability: Anticipating future growth and considering strategies like sharding, partitioning, or replication can help the database handle increased data volumes and user loads.
• Security: Implementing appropriate access controls, authentication mechanisms, and encryption techniques helps protect sensitive data and prevent unauthorized access.

17. Describe the concept of serverless computing and its relevance in full-stack development.

It is a cloud computing model where developers focus on writing and deploying code functions without the need to manage the underlying infrastructure. In serverless architecture, cloud providers handle server provisioning, scaling, and availability, allowing developers to focus on building application logic.

Relevance of serverless computing in full stack development:

• Scalability: Serverless platforms automatically scale the application based on demand, eliminating the need for manual scaling and infrastructure management.
• Cost-efficiency: With serverless, developers only pay for the actual execution time of their functions, leading to cost savings compared to traditional infrastructure models.

These full stack developer interview questions can greatly aid you in preparing for your next interview.

Wrapping Up:

Cracking interviews doesn’t solely depend on your skills and abilities, but also about your presence of mind. The way you frame your answers for general questions also speaks highly about your take on things and your ability to turn things in your favor.

If you’re interested to learn more about full stack software development, check out upGrad & IIIT-B’s Executive PG Programme in Software Development – Specialization in Full Stack Development which is designed for working professionals and offers 500+ hours of rigorous training, 9+ projects and assignments, IIIT-B Alumni status, practical hands-on capstone projects & job assistance with top firms.