Top 10 React Developer Interview Questions

Last Updated on 2024-10-11

Hiring React developers can be troublesome, especially for a non-technical HR manager. Here are React developer interview questions to help find the top developers for your needs.

As an entrepreneur, project manager, or CTO, you know that finding the right developers is the key to your project’s success. Hence the importance of having a well-mapped process for hiring software developers.

Yes, resumes offer a wealth of information about a job candidate’s skills and experience. However, the resume is not an indication that the candidate will be an excellent fit for your project or company. That’s why it is imperative to conduct interviews. During the interview, you can learn about a candidate’s job attitude, habits, and behavior, aside from testing their technical skills.

However, interviewing candidates for highly-technical positions such as React developer can be challenging for your HR manager. So, they must collaborate with your development team leader or tech lead. They can both work together in crafting technical exams and interview questions.

This guide will provide helpful interview questions to help you vet React developers. But before discussing React developer interview questions, let’s start with defining React developers and their job requirements.

React Development: What is React?

React is a front-end JavaScript library used by front-end developers to build user interfaces. Developers can use ReactJS as a base for developing single-page or mobile applications. Furthermore, React or ReactJS is open-source and free to use. Meta (formerly Facebook) maintains React together with a community of individual developers and companies.

In short, React helps simplify the building of websites and applications. It also makes it easier to build test cases and even reuse code from websites to mobile. With its advantages, it is not a surprise that most high-traffic sites like Reddit and Instagram use it.

What Does A React Developer Do?

They are front-end developers in charge of designing and implementing a website’s or an app’s user interface features using React. They are responsible for the user-facing side of a website or application. These include images, menu buttons, voice recognition, and motion or gesture-driven interfaces.

Here are some of their daily tasks:

• Collaborating with the development team to discuss UI ideas and requirements
• Developing and reviewing user interface designs
• Using React concepts to implement responsive user interface components
• Writing frontend code using JavaScript and ReactJS workflow
• Using and creating reusable components and front-end libraries
• Making sure that frontend components are optimized to perform across devices and browsers
• Troubleshooting and debugging interfaces and application code
• Supporting UI concepts by developing and implementing frontend architecture
• Monitoring, upgrading, and optimizing frontend performance
• Documenting changes and updates

These are just the most common React developer responsibilities. To make your job description more transparent, you should include specific tasks your project or company needs. Now, what do you look for from a React developer candidate?

React Developer Qualifications

ReactJS is a very powerful tool for front-end development. That’s why many companies are looking for React developers for their software development teams.

And to ensure that you get the right React candidates, you must check if they have the following qualifications:

• An IT, computer science, or any related field degree
• Proficient in JavaScript, HTML, CSS, and other frontend programming languages
• Must be knowledgeable about React tools (Enzyme, Flux, Redux, etc.)
• Skilled at user-interface design
• In-depth knowledge about performance testing frameworks (Jest)
• Must be expert at browser-based debugging and performance testing software
• Must be excellent in troubleshooting
• Project management skills
• Communication and interpersonal skills

The list shows that finding a suitable React developer can be challenging. And, the only way to ensure that you hire the best ones is to evaluate them further. To do this, you need to interview them.

Top React Developer Interview Questions

As mentioned before, interviewing job candidates is a way for you to evaluate their skills and attitude further. Hence, ask questions that allow the job applicants to showcase their technical skills and work behavior.

With that said, below are the top React Developer interview questions and what you should look for in their answers.

1. What is React? Why should companies use it?

This question can serve as an introductory question. It will help candidates feel more at ease as every React developer should know what it is and its advantages. 

In their answer, you should pay attention to how they explain React’s advantages. Their answer will show you the depth of their understanding of React and its concepts.

2. As a front-end developer, what programming languages are you most familiar with?

ReactJS is a tool for frontend development. Hence, candidates should be familiar with more than one front-end programming language. 

You might expect them to list some of the following:

• HTML
• CSS
• JavaScript

Their answer to this question should reveal their area of expertise and highlight potential knowledge gaps.

3. What is JSX?

It is a way to build a React user interface using simple HTML syntax. This question should test the candidate’s experience with React. By having them explain this process, you can evaluate their in-depth knowledge about React and its concepts.

4. How can you transfer data to React components?

This is another technical question. You should pay attention to how candidates explain Props and Context API. You can also ask them to write the code for these processes.

Here is an example of a good answer:

There are two ways to transfer data to React components. The first is through Props. Props are quite similar to arguments. It is an object that carries a tag’s attribute values.

The second way is through Context API. Context allows for producing more “global” variables that are easily passed around.

5. Differentiate State from Props.

States and props are two important components of ReactJS. The candidate should be able to explain the differences between the two. A good React developer should be able to define states and props using common terms that a non-technical person can also understand.

Here is an example of a good answer:

Simply, Props and States are values in React components. Their difference is that Props are used to pass values to React components. They are read-only and cannot be and should not be updated. On the other hand, States are values that can be read and updated in the React components

6. What is your process for testing your code?

Whether frontend or backend developers, self-testing code should be a must. Most developers would agree that testing their code is a sign of a great developer. You should pay attention to how often candidates test or troubleshoot their code and how they solve bugs.

Read 11 Tips for Improving Web Application Testing for some best practices on software testing.

7. In your previous job, what application interface components did you design?

The candidate’s answer will reveal their work experience and relevant design skills. Look out for candidates whose design skills and work experience match your project needs. They will be an asset because they will need a shorter training and adjustment period.

8. How do you prioritize which tasks should be done first?

React developers have a lot on their plates. A great developer should be able to organize and prioritize their daily tasks to avoid being overwhelmed. Hence, they should know which tasks to do to keep the application development process chugging along.

9. Have you ever made a big mistake at work? How did you handle it?

One inevitably makes mistakes in their career. Committing a mistake should not be seen as a weakness. When assessing the candidates, what is important is to know if they admit to their mistake and work to fix it.

This question will allow the job candidate to show their sense of humility, accountability, and transparency.

10. Do you have experience pitching an idea to your manager or team leader? How did you go about it?

In a software development team, communicating well is very important. Many developers have a hard time speaking up to their leaders. Thus, speaking up and presenting an idea will show the candidate’s confidence, awareness, and persuasiveness.

Use these questions further to assess the candidate’s fit for your company. You should add more specific and relevant questions during the interview.

Need Help Finding Great React Developers?

Having the best React developers in your software development team is a great asset. They make your website or application development more cohesive with their skillsets. They can help you bridge the gap between user-facing and server-side development.

Are you looking for experienced and skilled React developers? If yes, Full Scale is here for you!

At Full Scale, we recruit, assess, hire, and retain the best software developers. We hire less than 1 out of every 30 React developers we invite to interview. Why? To ensure that our clients are getting the most talented developers who also have the soft skills they’ll need to thrive. Take a look at our rigorous assessment process:

Our recruitment process ensures that our React developers and other specialists have the skills and experience to succeed as a part of your team.

Are you looking for world-class React developers? Get in touch now and let’s start building your team!