Full Stack Developer Interview Questions to Help Candidates

A high-quality full-stack developer is a versatile problem solver, adept at handling both frontend and backend development challenges. This role demands expertise across various layers of a project, making full-stack engineering one of the most exciting and in-demand positions in the tech world. To find the best talent, it's crucial to ask the right questions during the interview process.

In this guide, we’ll explore key full-stack developer interview questions that can help you identify top-tier candidates. With their ability to bridge frontend and backend development, full-stack engineers play a pivotal role in delivering efficient, seamless web projects. We’ll also break down what makes these developers essential to successful teams and highlight the answers that separate the best candidates from the rest.

Full Stack Developer Role

The day-to-day work of a full stack developer is one of the most varied and changeable roles in all of software development. Every industry, company, and team needs a different kind of developer to solve challenges unique to their technologies, team structure, and staff.

In the United States, a full-stack developer earns around $140,000 a year for their role in solving unique and interesting problems within a team. The responsibilities that come with this role include:

• Solving front-end challenges to make code highly functional and visually appealing.
• Creating back-end applications and databases to serve data.
• Designing server and client-side architecture that serves data efficiently.
• Testing, debugging and troubleshooting software problems as required.
• Writing effective APIs to facilitate connections as required.
• Ensuring the security and robust nature of software solutions.

Of course, the nature of full-stack development is that the role is consistently changing and adapting to the needs and challenges of each individual project. It's this variability and adaptation inherent to the role that are key reasons it's in such high demand amongst highly qualified and capable software developers.

Here, we have eight of the best questions to ask candidates and model answers to help top-tier full-stack developers stand out from the crowd during the all-important interview.

Key Full-Stack Developer Interview Questions

What technologies and languages would you need to decide on to start a brand new project?

• Find a suitable collection of technology frameworks. You need to choose one or more technology frameworks to suit the domain and goals of your project. For a mobile app, you might choose between React Native, Flutter, and Xamarin for example.
• Pick the correct programming language. You need to choose a language that suits the technologies and selected tools for development
• Choose suitable databases and data storage. Choosing the right DBMS (Database Management System) is crucial to making back-end development work smoothly and effectively in challenging projects.
• Decide on a robust and performant architecture. The architecture of your application will decide how reliable, performant, and maintainable it is for the lifetime of your project. Take a lot of time to work out the bugs and kinks here to save much more time and effort in the future.
• Find the right delivery network. In web applications, you will need a suitable server or marketplace to host your project. Here, you need to consider future demand, scalability, and requirements to ensure your solution works for a long time to come.

What are the main factors that will define successful integration?

• Maintaining a well-structured code repository.
• Automating the build and test process.
• Building the project after every code commit.
• Making the test build as close to the production environment as possible.
• Automating the deployment chain.

Explain the use of Docker in development projects today.

Docker is a highly popular tool for running virtual machines locally or in the cloud for development and testing. Docker has unique advantages for developers in that its virtual environments incur an extremely low overhead in comparison to more conventional virtual machines.

Docker allows teams to build test boxes for their applications to enable CI (continuous integration) testing to be readily deployed. Boxes can be deployed on a local machine, in the cloud, and even orchestrated as clusters that scale to meet demand.

What is a RESTful API?

REST (Representational State Transfer) defines an architecture that defines state-independent interactions between two RESTful web services. Developers can implement the constraints of REST architecture in a variety of ways.

The client makes a request to an endpoint and transfers information about its current state through any one of several technologies such as HTML, PHP, or JSON. A RESTful API has a number of distinct features that make it unique, these include:

• Each request between client and server is separate and unconnected. No state information is stored about the other on either end.
• Both client and server have a uniform interface to transfer information between each other.
• Functionality is extended with the ability to send executable code on demand from the server to the client.

Standardization is the primary advantage of today's RESTful APIs as they clearly define how components should communicate with each other.

What are some web development frameworks you regularly depend on as a full-stack developer?

It can be extremely helpful to know the technologies a developer uses and the projects that they've created in the past. Knowing what advantages of any given technology a developer appreciates can be a keen insight into what they value in a project and what technology features they prioritize in the development process.

If you need a refresher on the top web technologies currently being used in practice then our detailed guide on the highest performing web frameworks can highlight the key technologies and their advantages for future web projects.

Give an example of a project you have worked on; what were its biggest challenges and how did you solve them?

Details about previous challenges and projects are the best insight hiring managers will get into a full-stack developer's technical skill, communication, and practical ability. This one question is by far the biggest and most important question in any technical interview.

Candidates answering this question with lots of specifics and details is a strong indicator of future success. Clear reasoning for choosing one particular solution, toolset, or technology over another shows due care and consideration have gone into making a technical choice. A candidate that considers all the possible consequences of that choice is one you most likely want in your development teams. Similarly, the ability to reflect on the outcome of a project shows an ability to learn and grow from previous experience to make future decisions.

This question should demonstrate the most important factors of project development and an ability to make technical decisions that have a positive impact on a project

How do you keep up to date on new trends and thinking in web development?

This is a simple but important question in understanding a candidate's level of interest and involvement with the web development community. It invites further discussion on continuous learning, side projects, and meetups that are highly relevant to full-stack web engineering.

How do you keep up to date with the diverse languages and skills a full-stack developer needs to know?

Full-stack developers work across a wide variety of languages and technologies. Often, this means they are not as strongly invested in one particular language the way a native mobile developer might be in Kotlin or Swift. A full-stack developer needs to know how to implement solutions in Python, JavaScript, or C++ as needed.

Informal courses, personal practice, professional work, and side projects all have a role to play for developers. A good answer might talk about building a home media server, taking part in coding competitions, or attending technical meetups that use these skills for things outside of work or professional responsibility.

Practical Full Stack Engineering Interview Tips

Whether candidates are coming to this role for the first time or a highly experienced developer looking to land yet one more full-stack gig — no employer should expect a complete encyclopedia-like knowledge available at a moment's notice.

Being a full-stack developer is as much about learning on the job and thinking on your feet as it is using ingrained knowledge and experience to solve specific problems. The best full stack developers have a wide body of previous experience that they use to solve challenges through trial and error, continuous learning, and self-evaluation.

With strong answers to these top questions and an ability to solve problems well and think on the fly the role of a full-stack developer should be a breeze.

FAQs

Q1. How do I prepare for a full-stack developer interview?

The number one thing you can do to prepare for a full-stack interview should be to build and maintain a strong and current portfolio that shows off your best projects. The best insight a hiring manager will get into a candidate is by looking at the code, projects, and solutions a candidate has produced in the past. Display your best projects first and foremost and you'll be halfway there to breezing through the technical interview.

The next thing to do is to practice the interview questions and model answers that are likely to come up when meeting with hiring managers. Try and relate answers to your own experiences and projects as much as possible and be prepared to talk in-depth about work you've done in the past. Study the language and model problems as much as possible to prepare for technical tests and evaluations that are likely to be a part of the hiring process.

Q2. What is Full stack?

Full stack refers to the complete set of software and technologies used to build a platform, website, or application. Where front-end development refers only to the parts of an application a user can interact with and back-end development refers to the unseen engineering that makes everything work — full-stack development encompasses both areas and the communication between the two is essential to development.

The full stack includes everything from the browser UI technologies and software frameworks that support the libraries to the databases and foundational technologies that create a usable server.

A full-stack developer is an engineer responsible for developing a project at every stage. Often, they are experienced in both frontend and backend development and highly adept at creating solutions that work reliably to bring a project together through development, testing, and deployment.

Q3. What language does a full-stack developer use?

Full-stack development is one of the broadest skill sets in application development. Currently, the most popular languages of full-stack development are JavaScript, Python, C#, ASP.NET, PHP, and Java. Uniquely, full-stack developers typically rely on more languages day-to-day than most other developers.

A full-stack developer will often have to jump into a project to solve small problems in design, deployment, and testing as they arise. In practice, this means a full stack developer will need to write a small piece of code in Java or Python, for example, and then jump over to JavaScript to make changes to the frontend to carry that development through.

As a result of this skill set, there is a big demand for developers with skills and experience across multiple languages in both frontend and backend web development.