React Interview Questions — Hooks, State & Performance

React dominates Indian startup and product company frontend hiring. Interviews progress from JSX basics to hooks, performance optimization, and system-level component design.

Essential topics

• Virtual DOM and reconciliation algorithm
• useState, useEffect cleanup, useRef, useMemo, useCallback
• Controlled vs uncontrolled components
• Context vs Redux/Zustand trade-offs
• React 18 concurrent features overview
• Next.js App Router vs Pages Router

Build proof

Ship one polished portfolio app with routing, API integration, loading states, and accessibility. Walk through folder structure and state decisions in interviews.

Mock question categories

Explain why keys matter in lists, how to prevent unnecessary re-renders, and when to lift state up vs use global store.

Study React interview questions with easy to hard filters.