How To Interview Remote React Developers [Cheat Sheet]
Want to hire React Developers? Use our cheat sheet for the best tech assessment, as advised by our CTO, and go through this detailed article that includes positive and negative indications, as well as subquestions and more!
Luka Patarčić
There are so many things to consider when hiring a remote React developer. It can be quite confusing, and you might ask yourself: Where to start and how to assess the React developer successfully without cliche and unnecessary questions (that we all hate)?
Since I had a bunch of such interviews, I would like to share something that became really helpful and that I gathered from my experience.
But before that, if you need a React developer who is avaiable now, please check our vetted and avaiable developers on our platform.
Why wait: You can hire them NOW!
My name is Luka Patarčić and I am a CTO at FatCat Coders. Working on challenging projects and finding developers who were up for the challenge meant I had to understand their motivation, knowledge, skills, and basis.
Here are the key aspects for you to consider when interviewing React developers:
JavaScript and TypeScript: This is super important, as we want developers to know more than just React and pay attention to basic JavaScript skills.
Memory Management: Developers must understand how memory works in React, including memoization, rerendering, and garbage collection functions.
“Modern” React Questions: This indicates they are always learning new things and staying up to date with the most modern patterns and frameworks.
SSR vs CSR: This has become a standard and quite necessary, so it's important to ask questions related to Server Side Rendering (SSR) and Client Side Rendering (CSR).
HTTP and Backend Questions: It's important for a frontend developer to understand the HTTP protocol and how the backend functions.
Performance Optimizations: This indicates that the developer has taken the extra step in understanding and developing something that is more efficient than the basic solution.
These key points have helped me assess developers more effectively and ensure they have the necessary skills and knowledge for the role. Let’s start in detail with each of them!
To make this easier I have prepared the Cheat (Spread)sheet that can help you better assess React developers in a technical intervIew and that is available for free to use download.
Assess Their JavaScript Skills
It has become quite common for some developers to learn only React and not the fundamentals of JavaScript. This is why it is very important to assess their JavaScript language skills and see how much they know about in-depth JavaScript.
I have come across multiple developers who knew React very well and they could build complex React features and apps. On the other hand, they did not know much about the underlying fundamentals.
Now you might ask, if the developer knows how to build apps why do they need to know more about JavaScript?
Well, simply put, it matters when you are building apps to last. This means almost any developer can build a certain feature, but only a handful of developers can build a feature to last and be easily maintainable and scalable.
Understanding JavaScript fundamentally also enhances the ability to optimize app performance, which is essential in today’s developer ecosystem. Deep insights into JavaScript offer developers the versatility to innovate and build powerful applications.
This is what we mean at FatCat Coders when we talk about "work-proven” or vetted developers. It is not just about the technology, it is also about learning and fundamentals.
We focus on finding employees who are innovative and adaptable, proving their work, in terms of both successful internal and client projects.
Positive: The candidate really knows the JavaScript programming language, and understands the fundamentals and beyond. They can write clean and easy-to-understand code using modern patterns and syntax.
Negative: The candidate only knows the underlying framework and not the language itself. They know how to complete a task only using the framework but not the language.
Talk About Memory Management
Wait, wait, don’t roll your eyes—this is really important and something I have learned to look out for in developers. Imagine you have a feature that is quite resource-intensive and taxing. This is where this type of expertise comes in.
Developers who understand how memory functions in JavaScript and React are typically much better at writing more performant applications.
Now, of course, you could say: Well, in the newest release of React 19, there will be a compiler that will take care of all the memoization, rerenders, and other performance optimizations.
You are right, but this does not dismiss the need for a remote staff to be informed about this subject.
A developer's knowledge in this area can be the difference between an application that just works and one that feels fluid and engaging.
Positive: The candidate understands object references and how they are stored in memory. They also have experience with memoization in React.
Negative: The candidate does not understand how objects are stored by reference, not value.
“Modern” React Questions
Senior developers can become lazy with researching and staying up to date with the latest and greatest that any technology has to offer due to work overload and lack of motivation.
This is why I have learned that proactivity and willingness to learn are as important as prior knowledge and experience.
What I have gained from my experience is that asking people more “modern” questions, that are related to the latest updates and changes, can reveal their current knowledge and approach.
I also look at their way of answering the questions about the latest React things. People who are more enthusiastic about something will put in more effort in keeping up with the latest technologies and answering questions than those who are here “just to get the job done”.
Positive: The candidate is familiar and uses more modern React patterns and syntax such as for example: Suspense, Async, and Server Components.
Negative: The candidate still uses outdated patterns such as Class Components, has not heard about newer React patterns mentioned above, and in general lacks willingness to learn and adapt.
Still haven't downloaded?
Assess React Developers with 10 questions.
Learn positive and negative indicators.
Enhance with subquestions.
Server Side Rendering vs Client Side Rendering
This is quite a no-brainer question, considering the massive popularity of Next.js and its impact on the React ecosystem (including its pros and cons, as well as changes with Next v13).
I personally prefer SSR and have found many benefits compared to client-side apps. But this is not just about personal preferences.
Simply put, when someone understands SSR, they usually have a better grasp of backend technologies and how client-server communication works.
This is also a market and industry course of action. As the industry moves towards versatile developers skilled in multiple fields like frontend, backend, mobile, and DevOps, I've observed that those accustomed to diverse roles tend to be more proactive, communicate better, and are generally faster and more proficient developers.
For example, even if the developer is not utilizing all of the available tools and resources, it can become handy to know more about runtimes, the hot topics such as HTMX, or using appropriate AI for day-to-day work in JavaScript, industry changes such as the one with StyleX, etc.
Positive: The candidate has experience and has used some SSR patterns beforehand and can list the pros and cons.
Negative: The candidate does not know how SSR functions, they do not understand hydration and similar SSR patterns.
HTTP and Backend Questions
As mentioned above, I love asking frontend developers backend questions. This is not just to challenge them but, it is important to get a greater picture when you hire remote developers.
Of course, these questions are very generalized and do not go into much detail, but you can still get a sense of how much a developer understands what happens beyond the front end.
Usually, I like asking questions regarding the HTTP protocol, what it contains, and how we can communicate between the front end and backend. Knowing the basics is extremely important because all applications involve some form of communication between the client and server.
People who have a better understanding of how this communication works tend to write frontend code that is more effective and performs better.
From my experience, developers who have some experience with backend or just understand how it functions are generally better frontend developers than those who do not understand anything about the backend.
If you're unsure which questions to ask, be sure to check the free downloadable cheat sheet I've prepared for you. Under the 10th question, you'll find subquestions that will help you assess the candidate's HTTP knowledge.
Positive: The candidate knows basic request-response syntax, and understands headers, status codes, HTTP methods, cookies, SSL, etc.
Negative: If the candidate does not know the answer it can be justified by their seniority. Some developers, especially those focused on visual frontend development and CSS, may not be assessed on this topic.
Performance Optimization
For me the first thing that comes to mind when talking about performance optimization are algorithms.
Is it crucial to find a developer who knows algorithms and data structures? Not necessarily. While it's impressive when someone has that knowledge, my experience from both working on projects and interviewing candidates has taught me that it's not as critical as it might appear.
Algorithms are much more prevalent in backend apps and are not something that frontend developers utilize much in day-to-day tasks.
Rarely do we get the chance to display these types of skills when developing frontend applications, as these patterns more often apply to backend technologies.
I am not saying it is not useful or it does not matter, just not something that I personally look out for when interviewing front-end developers, having in mind that there are other aspects that are even more important.
Now, performance optimizations in React are really important and good to know. The most common and easy answers are something like virtual lists and how they can increase the performance of large data sets.
Positive: The candidate understands how the virtual DOM functions and is a copy of the actual DOM. Its performance implications and how it handles that within React.
Negative: The candidate does not understand anything regarding the virtual DOM which implies he could write poorer-performing applications that are more prone to bugs.
Downloadable Cheat Sheet!
As I mentioned previously, I have also prepared a cheat sheet to help you with the easier interview assessment of React developers. It encompasses 10 different questions that will help you determine if the React developer is suitable for you.
Here is what you will find here:
Questions: The primary questions that will help you evaluate key aspects of the candidate's knowledge that you want to assess.
What we assess: A detailed explanation of what we aim to evaluate with this question.
Positive & Negative Indicators: These will help you easily determine if the candidate is proficient in this area.
Subquestions: Additional questions that will allow you to delve deeper into the subject and learn more about the candidate.
This cheat sheet is available for free download and you can find it below.
Conclusion
These are just some of the things we here at FatCat Coders look out for when interviewing and assessing developers.
These things, of course, are subject to the company, role, and level. Some projects and tech stacks require different skills or expertise in specific libraries or patterns, so adjust these questions to suit your use case.
When hiring remote React developers, it is much more than just their knowledge of React and JavaScript. It is also important that the candidate is eager to learn and improve their skills.
And maybe most importantly, that they are a good fit for the company. Because at the end of the day, how well you work together in a team environment and collaborate matters most.
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