25 React Interview Questions & Modern Answers for 2026

React Interview Questions 2026: Hooks, Server Components, and Performance

React maintains 82% usage among professional frontend developers (State of JS 2025). React 19's server components and concurrent features are now mainstream, making them interview-essential. Interviews test: hooks, state management, rendering optimization, and React Server Components.

The three levels of React interview questions: 1) Fundamentals (hooks, lifecycle, JSX), 2) Patterns (custom hooks, context, error boundaries), 3) Advanced (server components, concurrent rendering, performance profiling).

Essential Topics

• Hooks — useState, useEffect, useMemo, useCallback, useRef, custom hooks
• State Management — Context API, Zustand, Redux Toolkit, React Query
• Performance — React.memo, useMemo, useCallback, virtualization, code splitting
• Server Components — RSC vs client components, data fetching patterns, streaming
• Testing — React Testing Library, component testing, integration tests

See frontend guide. Practice: AissenceAI coding copilot.