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.

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!

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.”

  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.

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.


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.

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.

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.

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)

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.

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