React.js interview practice
Practice React.js interview questions covering hooks, state management, performance, and best practices. Practice with an AI interviewer that scores clarity, depth, and answer structure — and tells you exactly what to fix.
React.js questions to practice saying out loud
Reading answers isn’t practice. Use these as your warm-up, then run a scored interview and hear yourself answer them.
What is the difference between useState and useReducer?
useState is best for simple state (primitives), while useReducer is better for complex state logic with multiple sub-values or when next state depends on previous.
Explain React Fiber.
React Fiber is the reconciliation engine rewrite enabling incremental rendering — splitting work into chunks, pausing/resuming, prioritizing updates. This enables concurrent features like Suspense and transitions.
What are React Server Components?
RSCs render on the server, reducing client JavaScript bundle. They can access backend resources directly, pass serialized data to client components, and enable zero-bundle-cost components for static content.