Full stack developers are skilled programmers who can work both with the front end and back end of a website or an application. They are responsible for developing and designing front end and back end web architecture, developing server-side applications, design databases, and much more. Besides this, full stack developers are also experts to solve the anomalies raised during different phases of development of an application or a website. In the past few years, the openings for full stack developer jobs have increased because these engineers are able to work with different technologies and languages.
The Weekday team has put together a list of full stack developer interview questions and answers that will help candidates prepare for this role. These questions have been hand-picked based on what you will likely encounter in the interview.
Describe an application you built and which technologies you used to build it.
How would you store a user's password on an online portal—and why?
There are many ways to store passwords, but only a few approaches are considered absolutely secure from the front to the back end. Ideally, the candidate will be able to explain which specific security features are essential. Candidates' answer to the second part of the question will shed light on how user data is protected from interface to databases. Interviewers will like mentions of how the candidate handled this scenario in a prior role, and references to plain text passwords, cryptographic hash functions (MD5 and SHA1), and salt.
If you had a month to develop a project from scratch, which frameworks, technologies, and programming languages would you use?
Being able to answer a complex question in a short amount of time is not easy. A highly qualified full stack developer won’t flinch. They should be able to describe their approach in a clear, concise way, while shedding light on their industry knowledge. Those who get flustered or have a difficult time may not be up for a challenge. Interviewers here look for answers that discuss specific development concepts, such as user experience, bugs, and other terminology. If the candidate is getting pushed back with a lot of questions, interviewers may see this as a red flag and conclude that they’re not ready for the challenge.
What is your favorite programming language and why?
Most full stack developers would have a very difficult time choosing one language among the many options available. Over their career, they will find that one language may be better suited to a project than another. Interviewers will see the candidates' answer as an indication on how much they’re engaged with the industry - and how deep their passion runs for their craft. A strong answer may reference past projects and any thoughts behind their programming choices.
Given the choice to specialize in front end or back end development, why did you choose to learn the full spectrum?
A developer, who can assess how a website or program should look and feel, while also understanding the technical limitations of the implementations, can see the big picture. Full stack developers are valuable to a team because they can address and discuss both aspects of the web development process - and bridge any disconnect. Interviewers here look for references to both front end and back end development projects. Candidates should convey the importance of being versatile and planning time wisely.
What would you do if you found inefficiencies in someone else's code?
Quality assurance is integral to the success of every implementation. Development projects often require a team of minds, and pointing out bugs or flaws is part of the territory. Interviewers here look for answers that demonstrate how much the candidate values precision, and the answer will also show them how comfortable the candidate is working with others. Interviewers also look for concrete details of the candidates' approach, how the colleague received the news, and what steps they took toward a solution. Strong answers will include references to this being a teachable moment for the greater good.
How do you keep up with the latest coding developments and programs?
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. Interviewers here look for answers that describe meetups, personal projects displayed in GitHub, or online learning platforms. Any mention of a lack of time to do so is a red flag, and signals the interviewer that the candidate can’t multitask and/or have no passion for the industry.
What’s the most recent thing you have learned?
This question is used to probe the authenticity of the information furnished in the last question. It is important that the candidate is aware of the latest in the industry and have a pulse of what’s happening. The candidate might talk about a website that they tested recently, or discuss a case study about a serious bug they recently read about. A point to note, the candidate should never give the interviewer an impression that they have learned nothing in the past 6 months. This is a fast-changing tech game, and being up-to-date with the current trends is an absolute must.
What are the most important qualities that a Full Stack Developer must have?
A full stack web developer interview will surely be incomplete without this question, especially at a fresher's level. A candidate should take time to talk about the competency required in various coding languages being the foundation stone on which a good professional can be built. The candidate should also talk about coordination skills that they would need while working in a team and mark excellent observation skills as a prime factor in working well in this role.
Discuss a time you struggled with debugging or another implementation issue.
Development can be a complex minefield, so nearly all full stack developers have had their share of barriers and roadblocks. The details of this answer are not as important as the willingness to discuss flaws or struggles. Essentially, if they haven't faced a challenge, they might not be as experienced as you need. Interviewers here look for indications that the candidate has a grasp on why they had difficulty, what they learned, and how they used the experience to move forward. Strong answers will mention asking for help or referring to their toolbox of resources for assistance.
What is the biggest mistake you did in any of your projects? How did you rectify it?
As they say, ‘No man is an island’. Similarly, no candidate can be working on technology and be right all the time. That is not imaginable. Candidates need to be honest here and talk about a mistake that they think was serious. It's important, however, for the candidate to also speak about their learning's from the mistake and explain the procedure they adopted to minimize the damage done.
The above questions are meant to help prepare you for the interview for a full stack developer job. In addition, no employer expects you to know everything, whether you are a newcomer or an experienced candidate. However, it is important to be well-prepared for the interview and demonstrate enthusiasm for the position. Once you are done with the interview, shoot off an email to the recruiter thanking them for the opportunity and ending with ‘looking forward to hearing from you’.