What are some of the most important React interview questions an interviewer can ask to assess a candidate’s practical skills?
When preparing for react interview questions, interviewers should focus on topics that test real-world application of React concepts rather than just theory. This includes understanding state and props management, component lifecycle methods, React Hooks (useState, useEffect, useMemo, etc.), and context API. Candidates should also know how to handle form inputs, conditional rendering, error boundaries, and performance optimization techniques.
Additionally, assessing practical skills in state management libraries like Redux or Zustand, routing with React Router, and asynchronous data fetching with tools like Axios or React Query helps identify developers who can build and scale production-ready React applications effectively.
When I interview React developers, I try to move past basic syntax questions and instead explore how they think about building real applications. I usually start with fundamentals like how they manage component state, what strategies they use to prevent unnecessary re-renders, or how they approach side effects using hooks such as useEffect.
But the key is presenting real-world debugging scenarios. For example: Why is a component re-rendering unexpectedly? or How would you split a large component tree for better maintainability? These types of questions reveal far more about a candidate’s practical skill than knowing what useState returns.
I agree with @tom-dale , real-world thinking matters more than memorizing APIs. To add to that, I like asking questions that show whether the candidate understands why React behaves the way it does.
For example, after talking about state management, I’ll ask them to explain scenarios where they’d use props vs state, or how they’d replace a class lifecycle method using hooks. Questions around Context API, lifting state up, or how they’d handle prop drilling naturally reveal their architectural thinking.
And performance is a must tools like React.memo, lazy loading, code splitting, or understanding the reconciliation algorithm tell me if they can optimize a production app, not just build components.
Both @tom-dale and @kumari_babitaa raise great points, so I usually take it a step further by introducing hands-on tasks. For example, I ask candidates to build a quick component with dynamic state or diagnose why a custom hook is misbehaving. This exposes whether they’ve actually worked through tricky issues before.
To evaluate real production experience, I ask about routing with React Router, global state patterns like Redux or Zustand, and how they manage data fetching with tools like React Query or SWR. These questions help differentiate someone who’s only followed tutorials from someone who has maintained and shipped real-world React applications.