CodeSubmit Interview Series

The 12 Top Junior Developer Interview Questions in 2023 

Looking to hire your next junior developer? If yes, you’ll need the right interview questions to help you identify the best candidate. Here’s a list of junior developer interview questions you can use in your hiring process.

Junior developer interviews

What should you look for in a junior developer? Junior developers should know basic programming languages, such as C++, HTML5, and JavaScript. Their code should be clean and maintainable and they’ll need to understand databases and operating systems. Ideally, your junior developers have basic programming experience, in the form of internships or similar. 

But how do you choose the right junior developer? Here are some of the best junior developer interview questions

Junior developer interview questions

Below are our top picks for interview questions to ask junior developers. Most importantly, look at your candidates’ overall answers rather than zeroing in on their technical abilities. How do they communicate? Do they understand your business? Are they open to learning? Junior developers don’t usually have a strong technical background, so factor that into your interviews. 

1. What is your preferred programming language? Why?


You probably have a language you’re hiring for. How familiar is your candidate with that language? And how well do your candidates understand the benefits (and shortcomings) of the language you use in your business? 

2. What steps do you take to troubleshoot your code?


How do your candidates troubleshoot code? This is one of the most important skills you should be looking for -- a developer who writes clean and maintainable code is a real asset for you. 

3. How would you improve our existing CSS framework?


This type of question shows you how well a candidate understands your goals and business. The answer will depend on the type of CSS you use. For instance, here they might suggest a different setup that streamlines your processes better. One common example is Semantic UI, which is difficult to customize and improve. The candidate might suggest Bootstrap, which can be a more streamlined option. 

4. How would you explain APIs to a non-technical team member?


This question shows you how candidates communicate with non-technical co-workers; something that can be critical for efficient teamwork. Of course, you can change APIs for another technical term. Ideally, their answer will be understandable to someone who doesn't understand technical jargon. 

In this case, they might reply:

“APIs are used for automating websites, apps, and software. For instance, APIs are used to show social media content on a website without having to upload the images separately.”

5. How do you ensure code quality?


Code quality is extremely important. Look for clues for how meticulous your candidates are. Do they analyze their code regularly? Do they follow code review best practices? And do they use a coding standard or are they open to using yours? 

6. What source control do you use? Why? 


Source control makes it easier for multiple developers to work on the same project. It’s a tool to keep track of different file versions and the source code of software projects. With a team of developers, you’ll want to make sure that they use a source control system or that you can train them to adopt the system you already use. 

7. Explain AJAX. When did you last use it and how? 


AJAX is a technique for creating better web applications with HTML, CSS, XML, and JavaScript. The name is an abbreviation of Asynchronous JavaScript and XML. Look for answers that reveal how your candidates understand AJAX and how they’re using it in their code. 

8. What IDE do you use? Why? 


Integrated Developer Environments (IDEs) are important for improving developer productivity. They combine common activities in a single application, including writing software, debugging, and editing source code. You’ll need to know what your candidates are used to, especially if you use a standard IDE in your organization. A few examples include Eclipse and Xcode. 

9. What’s the difference between white box and black box testing?


White box testing establishes a correct output given an input and the implementation of that function is correct. Black box testing, on the other hand, establishes an output given an input. 

10. How do you organize assets and class modules?


You likely have a set standard for writing code at your company. If yes, you’ll want to look for a candidate who takes the simplest approach instead of using overly complicated methods, so that you can maintain and document your code more easily.

11. What are the advantages of Git in web applications?


You could ask this same question of any tool or resource, really; the idea is to look for how candidates weigh the pros and cons of that tool. In this case, Git is a distributed version control system. It allows you to track changes to files in the system and revert back to past changes. Additionally, it doesn’t need a central server for storing all versions of the files within a project. 

12. Walk me through a project you’re most proud of. Why did that work out so well? What was your role in the team? 


You’ll likely want to ask a few of these types of questions. Look for your candidates’ analysis of the situation at hand. Do they understand why a project was a success? Could they use these learnings in the future? And if a team was involved, can they communicate the steps they took to work together with that team? Someone who takes all the credit is likely not an ideal fit for you if you require them to work with a team; after all, a team effort is a collaboration where different people have diverse strengths. 

Over to you!

There you have it. These are the best junior developer interview questions to ask in your technical interviews. 

Look for both technical knowledge and “soft skills” such as communication and teamwork skills. And to identify your next developer, combine your interviews with technical coding tests to assess your candidates’ technical skills.

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