React Interview Prep
Hooks, rendering, state, Server Components — drilled the way interviews actually ask them.
200 original practice questions across 6 domains, weighted the way interviews actually ask them. Like everything on this site, it runs entirely in your browser: no account, no tracking of your answers, no data leaving your device. Questions are written from the official documentation and versioned to current behavior.
The 6 domains
Hooks & Lifecycle
25%useState, useEffect, useCallback, useMemo, useRef, rules of hooks, custom hooks, stale closures — in virtually every React interview.
study →Rendering & Reconciliation
20%What triggers a re-render, keys, reconciliation, batching, concurrent rendering, useTransition and useDeferredValue.
study →State Management & Data Fetching
18%Local state vs Context vs Redux Toolkit vs Zustand trade-offs, lifting state, and TanStack Query for server state.
study →Server Components & React 19
15%Server vs client components, 'use client', Actions, useActionState, useOptimistic, SSR/SSG/streaming — the 2026 differentiator questions.
study →Performance Optimization
12%memo and useMemo trade-offs, the React Compiler, code splitting, list virtualization, profiling re-renders.
study →Testing React Apps
10%React Testing Library queries, user-event, mocking fetch, testing hooks and async UI.
study →How to use this track
- Curriculum — read the study notes for each domain, weighted like real interview loops.
- Practice — drill individual domains with instant explanations, then take the 50-question timed mock exam.
- Cheat sheet — the memorizable facts, condensed for the night before.
Other tracks: JavaScript & TypeScript
Independent community study resource — not affiliated with or endorsed by Meta Platforms, Inc. React is a trademark of Meta Platforms, Inc. All questions and study notes are original, written from the official React documentation. Everything runs in your browser; nothing you answer is stored or transmitted.