60+ challenges · 400+ interview questions · 12+ system designs

Master React.
Ace the interview.

Real coding challenges in a live editor, plus 400+ interview-question flashcards and system-design prep — everything you need to walk into the interview ready and get the offer.

Start solving free See plans

Trusted by 9,000+ engineers leveling up their React

Counter.tsxEasyFree

import { useState } from "react";

export default function Counter() {
  const [count, setCount] = useState(0);

  return (
    <div className="counter">
      <button onClick={() => setCount(count - 1)}>−</button>
      <output>{count}</output>
      <button onClick={() => setCount(count + 1)}>+</button>
    </div>
  );
}

preview

3 / 3 tests passing

Covers what interviews hit hardest: useState · useEffect · custom hooks · context · performance · forms · data fetching · error boundaries

400+

Flashcard questions

60+

React coding challenges

12+

System design problems

Why ReactPrep

Everything you need to get the offer

Practice in a real editor

60+ React challenges in a live in-browser editor — write code, run real tests, and check against a worked solution. The closest thing to the actual interview.

Real interview questions

Drill 400+ flashcards covering the React questions interviewers actually ask — hooks, rendering, performance — each with the how and the why so the answer sticks.

Track your progress

Save your work, watch your streak grow, and focus on the topics where you have the most to gain.

Ready to land your next React role?

Jump into the challenges, flashcards, and system-design walkthroughs. Start free, and unlock everything whenever you’re ready.