React Online Playground - Prototype Components in Your Browser

Running npx create-react-app just to test a component idea takes longer than the idea itself. A React online playground lets you skip that wait entirely and go straight to writing JSX.

What's a React playground online?

It's a browser-based editor where you can write React components -- functional components, hooks, JSX, the works -- and see them render in real time. No Node.js install, no dependency resolution, no waiting for webpack to finish its thing.

I reach for it whenever I want to try out a hook pattern, test how a component handles state transitions, or share a working example with someone. The feedback loop is tight: change code, see result.

Example: a counter with useState

Here's a simple functional component that tracks a count:

import React, { useState } from 'react';

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

  return (
    <div style={{ fontFamily: 'system-ui', padding: '2rem' }}>
      <h2>Count: {count}</h2>
      <button
        onClick={() => setCount(count + 1)}
        style={{
          padding: '0.5rem 1rem',
          fontSize: '1rem',
          marginRight: '0.5rem',
          cursor: 'pointer',
        }}
      >
        Increment
      </button>
      <button
        onClick={() => setCount(0)}
        style={{
          padding: '0.5rem 1rem',
          fontSize: '1rem',
          cursor: 'pointer',
        }}
      >
        Reset
      </button>
      <p style={{ marginTop: '1rem', color: '#666' }}>
        {count === 0 ? 'Click the button to start.' : `You clicked ${count} time${count > 1 ? 's' : ''}.`}
      </p>
    </div>
  );
}

export default Counter;

Drop that into OneCompiler's React playground and it renders immediately. No build step, no config files.

Why prototype React in the browser?

Setting up a local React project makes sense for real apps. But for everything else, an online editor is faster:

• Testing a hook -- does useEffect clean up the way you think? Try it in isolation without your app's other state getting in the way.
• Component prototyping -- sketch out a component's markup and behavior before committing it to your codebase.
• Sharing with teammates -- a link to working code beats a Slack message with a code block every time.
• Learning React -- if you're picking up React for the first time, the instant feedback loop matters more than project structure.
• Interview questions -- both giving and answering them. A shared playground keeps everyone on the same page.

Try React on OneCompiler

OneCompiler's React playground supports JSX, functional components, and hooks out of the box. Write a component, see it render, share the link. That's it.

If you find yourself reaching for create-react-app just to test something small, give this a try instead.