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Common Full Stack Web Developer Interview Questions

April 17, 2022

Full-stack web developers are constantly in demand. As someone who deploys a full range of frontend and backend web development skills, there’s often a lengthy or multi-step interview process before you receive an offer. As you prepare for your next interview, consider how you would answer some of these common full-stack developer interview questions.

General questions

Depending on where you are in the hiring process (e.g., phone screen, technical interview, or third-round interview),  you may be asked a series of questions about your general philosophy and skills as a full-stack web developer. These questions aim to verify your basic qualifications and to make sure you have the outlook and skills suitable to take on the role. 

What are the most essential programming languages for your job?

When interviewers ask this question, they want to know which skills you most commonly use in your ongoing work. Recruiters want to see if you have essential skills — such as Javascript, Python, and CSS — as well as familiarity with other languages, such as Rust or SQL.  “Candidates should list a variety of languages they find important to the job, not just one,” wrote the recruiting software company Betterteam.  

As you describe the languages and other skills you use in your daily work, try to list what you consider to be the benefits and limitations of each language. This helps establish your expertise as a full-stack web developer and makes you a candidate for leadership roles. 

What are some projects you’re currently working on?

This question aims to assess whether or not you are currently keeping your skills sharp, whether on a work project, freelance contract, or passion project on the side. Recruiters want to know how you use a range of different skills in your day-to-day work and are looking for someone who thinks outside the box when it comes to finding creative solutions. 

When you answer this question, it’s often helpful to use the “STAR technique.” STAR stands for Situation, Task, Action, Result.  Start by describing the project, explain what you had to deliver and the steps you took to complete the project, and finish with the end result. This approach tells a story that’s short and compelling and will work for many of the questions on this list. 

How do you stay up-to-date with current trends in web development?

Recruiters also want to make sure they’re hiring a full-stack web developer who is fully engaged with their work. Be prepared to talk about programming blogs, conferences, online courses, or forums that you participate in to keep abreast of everything that’s going on in the world of web development. If you have other side projects that you haven’t mentioned yet, make sure to talk about those here, too. 

Technical questions

As you move to the later stages of the hiring process, expect questions to get more technical in nature. Here are a few examples. 

How would you prevent a bot from scraping your publicly accessible API?

This is a little bit of a trick question. If data in the API is publicly accessible, then it’s technically impossible to completely prevent data scraping. Instead, a full-stack developer would approach the problem using rate limiting (e.g., throttling) to deter bots. Rate limiting puts a cap on how often a bot or person can repeat an action within a certain timeframe. For example, you could limit the number of times someone could attempt to log into an account. 

What are the key differences between GraphQL and REST?

GraphQL and REST offer two approaches to the same process: data transmission through IP such as HTTP. They differ in how they are implemented. 

“The main and most important difference between REST and GraphQL is that GraphQL is not dealing with dedicated resources, instead everything is regarded as a graph and therefore is connected and can be queried to app exact needs,” wrote the experts at dev.to

Put simply, GraphQL is a much more flexible approach than REST. You can find a nice summary with more information on how to describe the differences between GraphQL and REST in this resource.

What are some tactics you would use to improve a website’s load time and performance?

This question is a good opportunity to showcase your technical knowledge as well as your creativity and problem-solving. There are a number of ways to answer this question, including

  • Limiting HTTP requests
  • Utilizing CDNs and removing unused files/scripts
  • Optimizing files and compressing images
  • Browser caching and optimizing caches 
  • Applying CSS3 and HTML5

Talk through how you would approach optimizing the website, focusing on your process and teamwork in addition to your backend and design capabilities. 

Soft skills questions

Because full-stack developers are generalists, they’re often asked to manage other web developers. Full-stack web developers are great candidates for leadership positions; as a result, expect to get some questions targeting your soft skills. 

What would you do if you noticed a colleague made a coding error?

In this scenario, the recruiter is seeking to understand your communication skills and management approach. You may decide to talk about a specific instance in which you’ve dealt with this issue, or you can speak hypothetically. 

Because full-stack developers often interface with clients, a good answer to this question would probably refer to protecting the final outcome of the project over the ego of another developer. Talk about how you would correct someone’s work constructively, keep morale high, and proactively bring the project to fruition while keeping a detail-oriented approach to bug fixing and troubleshooting. 

What do you think is the most important character trait for a full-stack web developer?

This question directly refers to soft skills over technical knowledge. There are many ways you could answer this question. Recruiters value soft skills like organization, patience, flexibility, and creativity in those who fill full-stack web development roles. 

When answering, try to show that you possess the very skill you value. Talk about a specific situation that required you to put your patience to the test. Or talk about a project that got behind schedule, and how you were able to reorganize the team’s workflow to ensure deliverables were high-quality and delivered above expectations. 

Talk about a time you worked for a challenging client. 

Finally, some hiring teams might ask you to talk about a challenging client with whom you worked or a project that didn’t go according to plan. This question seeks to understand your people skills: how will you represent the company or the internal team? 

Note that this is not the moment to bad-mouth a past client. Regardless of what went wrong or who was at fault, make sure you keep your comments limited to how you resolved the situation and used your problem-solving skills. Recruiters often speak to other recruiters and companies, and can easily figure out who you’re talking about if you say something too negative. 

To learn more about preparing for a job interview, read our blog and apply to join our roster of top developers worldwide.

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