17 Junior Backend Developer Interview Questions and Answers

A Junior Backend Developer is responsible for the server-side of web applications. They work with Frontend Developers and UX Designers to ensure that the data transmitted to and from the server is consistent and correctly formatted.

If you’re applying for a Junior Backend Developer position, you can expect to be asked a variety of questions about your skills and experience. In this guide, we’ve compiled a list of commonly asked Junior Backend Developer interview questions, with sample answers to help you prepare for your interview.

Are you comfortable working with a team of developers to create new features and functionality?

This question can help the interviewer determine if you have experience working with a team and how well you collaborate. Your answer should highlight your ability to communicate effectively, work within deadlines and meet project goals.

Example: “I’ve worked on several projects where I was one of many developers contributing to the same goal. In these situations, we used communication tools like Slack or Basecamp to share updates about our progress and ask questions when needed. We also met regularly in person to discuss our progress and any challenges we were facing. These meetings helped us stay focused on our individual tasks while still collaborating as a team.”

What are some of the programming languages you’ve used in the past and which ones do you prefer?

This question can help the interviewer get a better idea of your experience level and how you’ll fit into their company. You should answer this question by listing some languages you have used in the past, but also explain why you prefer one over another.

Example: “I’ve worked with Java, C++, PHP, Ruby on Rails and JavaScript in my previous roles. I enjoy working with all of these languages for different reasons, but I find that Ruby on Rails is my favorite because it allows me to create web applications quickly while still being highly scalable.”

How would you go about debugging a code error on a live website or application?

Debugging is a critical skill for any developer, and the interviewer may ask you this question to assess your debugging skills. In your answer, demonstrate that you have experience with debugging code errors on live websites or applications.

Example: “I would first try to find out what caused the error by looking at the stack trace of the error message. Then I would check if there are any syntax errors in the code by using my editor’s built-in debugger. If it’s an issue with logic, then I would use breakpoints to pause the program so I can inspect values of variables and expressions. Once I’ve identified the cause of the error, I will fix it and test the website or application again.”

What is the difference between a database and a cache?

This question is a great way to test your knowledge of the two main components that make up an application. Your answer should include both definitions and explain how they differ from one another.

Example: “A database is where you store all of your data, while a cache stores only the most frequently used data. A database is more permanent than a cache because it’s slower but has better performance. Caches are faster than databases because they use RAM instead of hard drives, but they lose their data when the computer loses power. You can also have multiple caches in an application, but you need just one database.”

Provide an example of a time you had to troubleshoot a code error and what steps you took to resolve it.

This question is an opportunity to show your problem-solving skills and ability to troubleshoot. It’s important to be honest in your answer, as you may be asked to elaborate on the steps you took to resolve the issue.

Example: “I once had a client who was having issues with their website after making some changes to it. I started by checking for any syntax errors or typos in my code. After that, I checked the database for any inconsistencies. When I couldn’t find anything wrong there, I moved onto the server itself. I found that one of the PHP modules wasn’t installed properly, so I fixed that and the website worked again.”

If hired, what would be your primary responsibilities?

This question is an opportunity to show the interviewer that you have a clear understanding of what your role would be if hired. It’s important to highlight any specific skills or experience you have that make you qualified for this position, and it can also be helpful to mention how these skills will benefit the company.

Example: “My primary responsibilities as a junior backend developer include creating new features and improving existing ones by writing code in various programming languages. I am also responsible for testing my code to ensure it works properly and troubleshooting bugs when they occur. In addition, I regularly collaborate with other developers on projects to provide input and feedback.”

What would you do if you were assigned a project you were unfamiliar with?

This question can help the interviewer determine how you approach new projects and learn new skills. Use your answer to highlight your ability to research, ask questions and apply what you learn to your work.

Example: “If I were assigned a project that I was unfamiliar with, I would first do my best to understand the goals of the project and any requirements or specifications. Then, I would reach out to my team members for more information about the project. If I still had questions after speaking with my colleagues, I would contact my manager or other senior staff members to get answers to my questions. Once I understood the project better, I would use my knowledge to complete the assignment.”

How well do you perform under pressure and what is your process for managing deadlines?

The interviewer may ask this question to learn more about your time management skills and how you handle stressful situations. Your answer should include a specific example of a time when you had to meet a deadline, the steps you took to manage it and the positive outcome of meeting that deadline.

Example: “In my last role as a junior developer, I was tasked with creating an online store for a client who needed it completed within two weeks. At first, I felt overwhelmed by the task but then I broke down the project into smaller tasks and scheduled them out over the next few days. I also asked for help from other developers on our team so we could all work together to complete the project before the deadline.”

Do you have experience working with code versioning tools?

Version control is a key skill for any developer, and the interviewer may ask this question to see if you have experience with specific tools. If you do, share your experience using them, and if not, explain why you would learn how to use them.

Example: “I’ve worked with Git in my previous role as a junior backend developer, and I find it’s an effective tool for managing code changes. It allows me to keep track of all the different versions of code that I create so I can easily go back to older versions when needed. I also like that Git makes collaboration easier because multiple developers can work on the same project at once without overwriting each other’s work.”

When should you use a synchronous request and when should you use an asynchronous request?

This question helps the interviewer assess your knowledge of how to use different types of requests in a backend development environment. Use examples from past projects where you used synchronous and asynchronous requests to explain your reasoning for using each type.

Example: “Synchronous requests are best when they’re being used on a single thread, while asynchronous requests should be used when there’s more than one thread involved. For example, I once worked with a client who needed an application that could handle multiple users at once. In this case, it was better to use an asynchronous request because we were able to create a system that allowed multiple users to access the app simultaneously without any issues.”

We want to improve our code documentation. What is your strategy for doing so?

This question is an opportunity to show your interviewer that you have the skills and knowledge necessary to improve their company’s documentation. Use examples from previous projects where you improved code documentation or created new documentation systems for your team.

Example: “I’ve found that one of the best ways to improve code documentation is by using a wiki system. I used this method when working on my last project, which was creating a new website for a local business. The client wanted us to create a user-friendly website with detailed instructions on how to use it. We decided to use a wiki system so our developers could update the site as needed without having to send out updates to the client. This allowed them to make changes themselves and saved time and money.”

Describe your experience with object-oriented programming.

This question can help the interviewer determine your experience with a specific type of programming. Object-oriented programming is a method that uses objects to create software applications. Your answer should include information about what you’ve done in this area and how it helped you develop your skills as a developer.

Example: “I have extensive experience using object-oriented programming, which has helped me understand how different types of software interact with each other. In my last role, I worked on an application that used object-oriented programming for its database management system. This allowed me to work more efficiently because I could use one set of code to manage multiple aspects of the program.”

What makes you a good fit for our company?

This question is a great way to show your interviewer that you’ve done some research on the company and are excited about the opportunity. When answering this question, it can be helpful to mention something specific about the company’s mission or values that resonates with you. You can also talk about how your skills and experience make you an ideal candidate for the role.

Example: “I think I would be a good fit for your company because of my passion for technology and my commitment to customer service. Your company has a reputation for being one of the best in the industry when it comes to providing excellent support to customers, which is something I strive for in my work. I’m also very passionate about developing new technologies that help people solve problems, so I was thrilled to learn more about your company’s products.”

Which programming languages do you wish to learn in the near future?

This question helps the interviewer determine your commitment to professional development. It also shows them which languages you are already familiar with and how much experience you have in the field. When answering this question, list a few programming languages that interest you and explain why you want to learn them.

Example: “I am currently learning Python, but I would like to expand my knowledge of functional programming languages such as Scala and Clojure. These languages are highly efficient for backend development because they allow developers to create reusable code. This saves time when creating applications or websites.”

What do you think is the most challenging part of being a junior backend developer?

This question can help the interviewer get an idea of how you approach challenges and solve problems. Your answer can also show the interviewer your problem-solving skills, critical thinking skills and ability to adapt to new situations.

Example: “The most challenging part of being a junior backend developer is learning all the different programming languages that are used in the industry. There are so many different types of coding languages out there, and I find it difficult to remember them all. However, I have found some ways to make this process easier for myself. For example, I use flashcards on my phone to study when I’m waiting in line or riding the bus. This helps me learn the languages more quickly.”

How often do you update your knowledge of programming languages and technologies?

This question can help the interviewer determine how much you value continuing your education. It can also show them what steps you take to stay up-to-date on industry trends and developments. In your answer, try to explain that you are willing to invest in yourself by taking classes or participating in online training programs.

Example: “I am always looking for ways to improve my programming skills. I have taken several courses through Udemy and Code Academy where I learned about new languages and technologies. I also subscribe to a few technology blogs so I can learn more about the latest advancements in the field. I find these resources very helpful because they allow me to continue learning even when I’m not actively working.”

There is a bug in your code. How do you handle it?

This question is a great way to test your problem-solving skills. It also shows the interviewer how you handle challenges in your work environment. Your answer should show that you can use critical thinking and analytical skills to solve problems.

Example: “I first try to understand what caused the bug. Then, I look at the code line by line to see if there are any issues with it. If I find the issue, I fix it immediately. If not, I will then check for other bugs or errors in the system. Once I have fixed all of these issues, I run the program again to ensure everything works as expected.”