React (also known as ReactJS or React.js) is one of the world’s most widely used JavaScript toolkits for building user interfaces (UIs). As of June 2024, more than 45 million live websites were using React on their front end: Beyond Meta’s own Facebook, Instagram, and WhatsApp, other leading enterprises like Uber, Airbnb, Shopify, Netflix, and Amazon also rely on React developers to achieve their business objectives. This means React is central to the technology landscape for modern applications. With more than a decade of maturity behind the platform and Meta’s vested interest in actively maintaining and improving it, React is not only the front-end framework of choice for many seasoned professionals, but also the default recommendation for novices.

According to the State of JavaScript 2022 survey, React has shown strongly rising popularity since 2016 and was listed in the survey’s “A” tier for retention and continued use among developers who had tried out the package. Growing steadily more popular since its release, React was downloaded almost 25 million times as of June 2024, according to npm trends. As a result, React developers remain by far the most dominant group when it comes to front-end hiring trends, per May 2024 Hacker News Hiring Trends data. Having a steady pool of React developers for hire (from among millions) provides many opportunities for companies who need them—too many, in fact.

With such a high demand, finding the right freelance React developer for your project requirements can be an enormous challenge. This guide highlights the key qualities to look for as you hire React programmers and will help you carry out your hiring process to find the right person for your organization and project.

What Attributes Distinguish Quality React Developers From Others?

Broadly speaking, React developers create and maintain code that works with the React framework to produce the visible part (i.e., the front end) of a website or app. For smaller projects, companies may rely on a React developer to cover adjacent responsibilities too—everything from UI or user experience (UX) optimization to accessibility assessments, graphic design, SEO, and even back-end development (in the case of a full-stack role). Larger projects will engage specialists in such aspects, leaving React developers to concentrate on leveraging their core skills; an extensive skill set is needed to use React to produce the high-quality, responsive UIs the framework is famous for.

Core Competencies for React Developers

React experts can describe the best practices they employ and how these techniques make a noticeable impact on the reliability and overall ROI of a project as they bolster code quality. The following general qualities and soft skills are important to look for when hiring React developers:

Mastery of the React ecosystem — Broad familiarity with the React ecosystem saves company time, allowing developers to leverage trustworthy third-party libraries and tools rather than coding them from scratch. React experts should be familiar with React design patterns, hook-based techniques, and debugging tools. In addition, mastery of state management libraries like RxJS lets developers maintain and scale their web apps as feature complexity grows. Their extensive experience with the React component life cycle and methods like shouldComponentUpdate allows rendering optimization and side effects management, minimizing bugs and ensuring optimal application performance.

Library management and component reusability focus — React is especially well suited for developing libraries of reusable class components. When you hire React.js developers, look for candidates with excellent library management skills and extensive experience developing components in React that can be reused across teams and projects.

Testing React applications — Building a continuous integration or deployment environment in which every pushed commit is automatically tested—and, if successful, deployed—has become standard practice. Conducting unit and integration testing helps to catch bugs before they happen, building user trust and boosting revenue. When it comes to testing, React has many libraries available, and candidates should have familiarity with one or more of the popular options, such as Jest (based on Jasmine), Mocha, or Karma, as well as the ReactTestUtils library.

Design thinking — Design thinking is important for everyone involved in development, but it’s especially important for React programmers who build UIs. Even when working with dedicated UI and UX designers, React experts must have a profound understanding of modern design principles to craft effective and responsive UIs. As a contributor to the webpage’s front-end development, a React engineer’s job often consists of transforming a designer’s wireframe into functioning, deployable code.

Problem-solving and attention to detail — ReactJS programmers have to solve many problems and manage complexity while building modern UIs, which typically make use of multiple toolkits, packages, and components and interact with a variety of back-end systems. Moreover, while attention to detail and its consequences for code quality is important for all software engineers, front-end software directly impacts UX, and even the tiniest flaws will be clearly visible to users and customers.

Communication skills and understanding business goals — As part of a development team, a React developer for hire has to be able to work well with peers, seniors, and juniors. The give and take of roles, from requirements through quality assurance, necessitates professional and responsive communications at all times. Moreover, developers must understand that commercial applications exist to fulfill business objectives. Web and mobile app developers have to keep their organization’s business requirements in mind throughout the development process.

Complementary Technology Skills for React Developers

Given that React is a front-end web technology, React programmers are required to have several standard front-end skills to ensure a seamless user experience on your app. The following skills and programming languages are in addition to the wider ecosystem of common JavaScript tools, such as Babel, ESLint, and webpack:

HTML5 and CSS3 skills, along with Document Object Model (DOM) mastery — Since a substantial percentage of React applications will be deployed on the web and will interact with HTML and CSS, React developers must understand these standard web technologies. HTML defines the internal hierarchy, called the DOM of a webpage. One of React’s strengths is its ability to map a virtual DOM to the real DOM. Understanding the DOM is essential for React developers. CSS code defines the styles used by webpage elements, regardless of whether they’re static or dynamic.

JavaScript — At its core, React is a JavaScript library: JavaScript is the scripting language React is made in, and is what makes React applications dynamic and interactive by modifying the DOM and communicating with servers after the page has loaded. React also comes with a language created specifically for it called JSX, which is a way of combining the syntaxes of JavaScript and XML (similar to HTML) to create compact, readable definitions for both class components and functional components. All candidates should have a deep understanding of JavaScript fundamentals, such as variables, objects, and functions, as well as software development concepts like conditional statements and iterating through datasets.

Angular, Vue.js, and other alternative toolkits — While React is an excellent toolkit, sometimes other toolkits such as Vue.js and Angular may provide superior components and results when used in combination with React, along with specialized React developer tools. Skills in alternative frameworks may not be an absolute requirement, but having a general idea of how they work helps candidates understand different methodologies, making them more adaptable developers with a broader toolkit they can use to solve problems.

Redux — Managing state in React can be difficult, especially as applications grow in size and complexity. Larger React codebases can benefit from the well-organized approach that Redux—an open-source JavaScript library that centralizes state management—provides. This is especially true of apps that have a lot of global application states to manage, frequent state updates, and/or complex state update logic. The Redux project provides related tools like Redux Toolkit, which helps React developers follow state management best practices, and the Redux DevTools Extension, which vastly simplifies the troubleshooting and inspection of internal data flows via powerful features like time travel debugging.

Back-end skills — While React is a front-end technology, knowledge of entire development workflow, including server-side technologies, is extremely helpful for integration and testing. Back-end platforms and programming languages include Laravel (PHP), Django (Python), and .NET (C#). Node.js is a server-side runtime environment that uses JavaScript. React engineers will also benefit from knowing how to interact with databases and communicate with servers using REST APIs or GraphQL.

Mobile and cross-platform deployment skills — React is also used for mobile applications, so iOS, Android, and other mobile app development skills will often be necessary depending on the nature of your project.

Git — Even the smallest project needs source code version control, and Git remains the most popular tool for it. Unless your organization uses an alternative like Mercurial or SVN, the React developers you hire will need at least basic Git skills, and your team would be well advised to establish an overall Git strategy (such as enhanced Git flow) if it hasn’t already. If your team is growing but lacks someone with advanced Git skills, consider vetting your React developers for this as part of your hiring process.

How Can You Identify the Ideal React Developer for You?

While it’s desirable to find a candidate whose skills and experience match the general qualities listed above, when hiring a dedicated or freelance React developer, you also have to consider your company- and project-specific needs and conform to your business process for hiring. If you try to hire React engineers without an awareness of the specific skills gap they’re meant to fill on your team, you’re relying on chance to provide you with a good fit. At best, you may waste time pursuing someone to underuse their skill set; at worst, you may hire an underskilled developer and place excessive expectations on them, leading to frustration rather than successful projects.

Before you search for candidates, it’s best to have a clear and realistic view of your project requirements and the impact you expect your new hire to have on your team:

How far along is your React project?

The size and scope of your project, as well as the number of milestones left to achieve, is a significant factor in the type of developer you should be looking for. Adding a few features to a mature app is much more straightforward than creating a project from scratch, which requires senior-level expertise and architectural abilities. For a short-term project just needing support to get to the finish line, you may not need to hire dedicated ReactJS developers; instead, consider outsourcing to freelance candidates working on a project basis.

Which technologies—besides React—does your project rely on, and what are the additional skill requirements?

Consider which additional technologies your project uses, and which ones you’d like the candidate to be familiar with. Think about which are absolutely essential, and which ones are just nice to have. You may have a skills gap that you are trying to fill. There are also technologies that you won’t need at all; for example, if this is going to be a web-only project, the candidate doesn’t need mobile app experience.

Who will your new React developer work with, and in what capacity?

Analyze the skills your team currently has, identifying the areas where they are strong, as well as any skills gaps. If your organization needs to combine front-end and back-end experience in a single developer, you’ll want to hire top full-stack experts whose expertise includes both React and your back-end tool set. You may also seek front-end specialists to refine your UI.

Will your new hire receive React-specific mentorship or be expected to provide it?

The overall experience level of your existing development team plays an important role in the type of developer you hire. Many talented teams benefit from the addition of a strong lead developer. A team may also have an established lead who can onboard and mentor new ones. Junior developers’ productivity is driven by oversight, while top ReactJS developers thrive on independent work.

In addition, every sector has its own special needs. Look for skilled developers whose portfolio contains engagements that match the type of application being built. An e-commerce front end is naturally quite different from a database search front end or a dating platform front end.

React Developer Experience Levels

Another important consideration is React engineer seniority and experience levels. When hiring a sole developer or filling a lead slot, you will generally want to find the most experienced senior developer available. But sometimes the budget may constrain your options, and when hiring for a team role, a junior developer can often provide just the right skills at better pricing. Apart from years on the job, different skills distinguish junior and senior ReactJS developers.

Junior React Developers

Junior developers have one to three years of experience and are proficient with the most important React skills, including building reusable UI components with JSX, using props to pass data, managing component state, and unit testing React components with libraries like Jest and React Testing Library. They’ll have some skill with more recent ECMAScript standards (from ES6/ES2015 through ES2024), allowing them to structure JavaScript code in cleaner, more efficient, and more readable ways with features like destructuring, template literals, and arrow functions. They can use CSS to style reusable components in React and create basic interactivity via useState hooks. Junior developers are comfortable working in an Agile environment and completing routine tasks, such as adding small features to a preexisting app, and might require supervision to understand and conform to team coding standards without introducing bugs.

Mid-level React Developers

Mid-level developers have three to five years of experience and can perform more advanced tasks, such as building more complex and dynamic UIs, optimizing components, and integrating external APIs. Their state management experience includes the more capable approaches that RxJS, Redux, and MobX provide, so that state from disparate app components (e.g., options and user authentication) is handled properly regardless of app usage patterns. Working on larger apps has honed both their skill with React Developer Tools and their ability to design architecture in a way that promotes code reusability using patterns like hooks and composition to keep their code readable and maintainable. This is also true of their approach to routing and navigation: They’re equally comfortable working on single-page applications or traditional ones, and handling nested routes and dynamic parameters to allow navigation structures that match the complexity they need as an app’s feature set grows. For many projects, they can be trusted to turn sets of business goals into entire applications without much outside assistance and can provide mentorship to junior developers.

Senior React Developers

Senior developers have more than five years of experience and can tune and scale large, complex applications. They know how to keep an app performant using techniques like code-splitting via lazy loading, dynamic imports, and both React.memo-style and useMemo-style memoization. They can design scalable applications and are experienced with containerization and deployment strategies using Docker or Kubernetes. Their experience with React design patterns like container/presentational components lets them refactor React applications as needed and ensure codebases are well suited for automated testing, which is essential for reducing bugs and avoiding their recurrence. They use unit tests, integration tests, end-to-end tests, and tools like React Testing Library, Jest, or Enzyme to ensure the robustness of new releases. They also know how to speak the language of back-end developers to ensure that integration is seamless between the front and back ends. Senior ReactJS developers are the leaders of the development team, defining the architecture for React apps, mentoring junior developers, communicating with stakeholders, and leading code reviews in order to maintain a high level of quality in the final product. They are comfortable wearing multiple hats, performing project management and design duties, and may eventually move into leadership roles or co-found startups.

How to Write a ReactJS Developer Job Description for Your Project

The keys to writing a good job description for a React developer are clarity and priority. The text must communicate your needs clearly and should specify key skills, the nature of the position (whether you seek junior or senior, fixed-term or permanent, on-site or remote ReactJS developers) along with other basic features of the role, like salary range. For a freelance React developer role associated with a particular project, the job description should make the project and its scope clear as well because you’ll be looking for someone whose past experience matches that particular project as closely as possible. It’s also worth including the structure of your team so candidates will have an idea of the level of support they will have, the time zones of team members, and how they will collaborate with colleagues.

Within the description, your most important needs should be listed up front and marked as mandatory requirements for applicants. Certainly, React expertise is the main focus, but if you already know additional packages and toolkits that will be used, those can be listed as nice-to-haves. If you want someone to take charge of a React development project, or if you’re hiring a team contributor, say so up front. List any relevant soft skills, such as leadership or conflict management. If the role touches on any other major technologies, you’ll want to include relevant parts from their job templates too. For example, a full-stack role might be for a project already hosted on Google Cloud Platform, Azure, or Amazon Web Services (AWS).

Finally, should you write “React,” “React.js,” or “ReactJS”? Officially, it’s “React,” but advertising that your development company would like to hire React.js developers rather than React developers won’t deter any worthwhile candidates, who are used to seeing some varied nomenclature.

What Are the Most Important React Developer Interview Questions?

Since React development processes rely heavily on common web technologies, a good React developer interview will not only include React interview questions—and discussions of relevant best practices—but also ones about JavaScript, HTML, CSS, and any other technologies your next project may happen to rely on. The answers to these technical questions should be evaluated by skilled React experts.

However, before starting the interview process, it is important to ask, “What strategies can a hiring manager implement to verify a candidate’s past work experience, React proficiency, and reliability?”

Before Getting Started: How Do You Evaluate a Candidate’s React Experience?

In addition to assessing a React developer’s technical abilities during the interview, you may wish to analyze the candidate’s CV and portfolio, examine their digital presence (e.g., social media and blog posts discussing React), and check their employer references. It can be useful to recruit the assistance of an in-house React expert to verify the candidate’s experience across these areas and during the interview.

The candidate’s CV should make clear which of their past assignments used React and to what extent. Recent assignments should come with links to websites or apps crafted by the candidate. The candidate should be able to explain their visible contributions to those sites and apps in detail. If a candidate uses GitHub, their projects visible on this platform should make use of React. However, it’s entirely possible for a legitimate React expert to have few visible projects if they’ve been working primarily on closed-source projects. In that case, cross-check their portfolio against previous employer and colleague references.

During the interview, the candidate should demonstrate confidence in their responses to pressing questions about React experience and be able to detail the nature and scope of their work on past assignments. Additionally, take-home assignments or technical questions are useful in assessing the React developer’s level of expertise. These should focus on skills relevant to the project that will be used on a day-to-day basis. It is a good idea to start with more basic questions focusing on UI design, HTML/CSS, and JavaScript fundamentals before moving on to more complex topics like state management and local styles.

What are React’s strengths and weaknesses? How do you play to its strengths, and how do you shore up its weaknesses?

All toolkits have strengths and weaknesses. A skilled React developer will know how best to use the framework and when to use other tools alongside React. Some commonly mentioned issues with React include that on its own it is only a toolkit and not a complete framework; it has a steep learning curve; issues exist with JSX (which React relies on); and there are issues associated with debugging complex React projects. The question allows the candidate to demonstrate their knowledge about React in broad terms. Keep in mind each of the strengths and weaknesses that the candidate lists; these are good starting points for discussions about specific functionality.

Explain the difference between stateful and stateless components and describe the situations in which one or the other type is preferred.

This is an example of a detailed technical question a React developer should be able to answer with ease. Stateful components manage information over time, handle complex application logic, and interact with an application’s back end, while stateless components are best for presenting ephemeral information to end users. Candidates should have a deep understanding of state and state management, as it is very common in web development.

What are higher-order components (HOCs) in React? How do you use them?

Skilled React developers, particularly mid-level and above, should have knowledge and real-world experience using HOCs because they promote code reusability, maintainability, and separation of concerns. HOCs are functions that take a component as their argument and return a new one; in essence, they are wrappers. They can be used to extend or modify the behavior—including the rendered output—of the contained component. Using components this way is well characterized by the decorator pattern in React. Strong candidates should also know the pitfalls of HOCs. For example, HOC-injected props may conflict with preexisting component props, and too much HOC nesting can reduce codebase readability. Your candidate should be able to suggest React hooks as an alternative way to share stateful logic without increasing the complexity of the component hierarchy like HOCs do.

Describe the concurrent features available since React v18.0 and how you would use one of them.

React’s concurrent features allow for interruptible rendering and handle it in a user-friendly way. They do this by rendering in the background instead of blocking the main thread and keeping DOM mutations until a render is complete. React v18.0 and later versions let you mark an update as either urgent (the previous default, now intended only for reflecting direct user interaction like typing) or transitionary (for less immediate updates, such as fetching autofill results). Candidates should also know how to do the latter within a component via the useTransition hook and the startTransition function it returns, and that there’s a stand-alone startTransition available for use outside of components.

What does React’s automatic batching do, and how is it enabled?

When using the ReactDOM.render method directly, React will try to reduce rerendering by grouping updates, but it can only batch those that occur within React event handlers. Automatic batching goes a step further by including asynchronous updates, such as those occurring in promises, native event handlers, and functions passed to setTimeout. To enable automatic batching, a developer has to create a root with ReactDOMClient.createRoot and only then call the render method of the returned root object (instead of ReactDOM).

What is JSX? How does it work, and why would you use it?

JSX is an XML-like syntax that simplifies the code when creating components. However, JSX is JavaScript, not XML; React transforms the JSX syntax into pure JavaScript. In many cases, JSX makes the code easier to understand, especially for those familiar with HTML and XML. Being able to decipher JSX syntax is an essential skill for a candidate because they might be tasked with debugging or maintaining code that uses it.

Why Do Companies Hire React.js Developers?

React is currently the leading front-end toolkit for building web applications and high-end solutions, and is also a crucial part of the development process for many mobile applications thanks to React Native. Seeking ReactJS development services is an excellent choice for new projects, and existing projects are likely to be using React already.

React is particularly noted for building reusable components that allow developers to standardize UI appearances and functionalities across projects. Focusing on code reusability leads to increases in development speed and code quality, as well as more easily maintainable code. Because of its popularity, React has broad developer community support from millions of programmers worldwide and has many compatible toolkits and supporting libraries available for specialized functions. React is also known for the flexibility and convenience of its virtual DOM model and its exceptionally fast UI rendering. Because React can be used for both web and mobile applications (including both iOS and Android), the same codebase can be used across multiple platforms.

In all cases, an engineer’s quality of work directly impacts the UX of a company’s end product, so it’s essential to hire ReactJS developers whose strengths are sufficient to stand alone or complement an existing development team, depending on your project resources. Using the job description and interview question advice in this guide, you now have the background to define and advertise your business requirements, attract and vet a React developer of the appropriate caliber, and, finally, find the perfect match needed for your project’s success.