Free React live preview

React JSX playground with live preview

Prototype React components with JSX in the browser, then prove JS skills on coding problems and frontend tutorials.

Open React runner JS problems Coding practice

1 Try Run React
2 Tool Format & mock
3 Prove Coding / assess

React scratchpad

Free run — no login. Rate-limited. Same runner as the multi-language hub.

Source

function App() {
  const [count, setCount] = React.useState(0);
  return (
    <div style={{ fontFamily: 'system-ui', padding: 24, background: '#0f172a', color: '#e2e8f0', minHeight: '100vh' }}>
      <h1 style={{ color: '#38bdf8' }}>React playground</h1>
      <p>Edit this component and click Preview.</p>
      <button onClick={() => setCount(count + 1)} style={{ padding: '8px 14px', borderRadius: 8 }}>
        Clicked {count} times
      </button>
    </div>
  );
}

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(<App />);

Preview

Press Run to execute.

After you try React

Frontend tutorials JS problems Coding practice

How to use this React compiler

Edit the React sample (JSX is supported via Babel in preview).
Click Preview to render into the sandboxed frame.
Keep components small while exploring hooks and UI.
Open frontend tutorials or JS coding problems next.

Tips

Use React and ReactDOM globals — no import lines needed in this sandbox.
Prefer function components and hooks for interview-ready habits.
Use Code Diff when refactoring a component.

Tools for this stack

Format, mock, or diff — then come back and re-run.

Full toolbench

Code Diff Compare snippets side by side before you submit. JSON Formatter Pretty-print API payloads before you paste them into code. HTML Formatter Clean markup when you are prototyping UI snippets.

React playground FAQ

Do I need Vite or Create React App?

No. Preview compiles JSX in the browser for small demos.

Can I use npm packages?

Not in this sandbox. Keep demos self-contained; use a local React app for libraries.

Where do I practice after this?

Frontend tutorials, JavaScript coding problems, and Skill Assess.

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