React vs Preact: Key Differences and When to Use Each

React is a full-featured UI library with a large ecosystem, while Preact is a smaller, faster alternative with a similar API but fewer built-in features. Use Preact for lightweight apps and React when you need extensive tooling and community support.

Quick Comparison

Here is a quick side-by-side comparison of React and Preact on key factors.

Factor	React	Preact
Size	About 30 KB (production, minified)	About 3 KB (production, minified)
Performance	Good, optimized for complex apps	Faster initial load, smaller footprint
API Compatibility	Full React API	Mostly compatible with React API, some advanced features missing
Ecosystem	Large, many third-party libraries	Smaller, but compatible with many React libraries
Features	Includes hooks, context, concurrent mode	Supports hooks and context, no concurrent mode
Use Case	Complex apps needing rich features	Lightweight apps or performance-critical projects

Key Differences

React is developed and maintained by Meta (formerly Facebook) and offers a comprehensive UI library with features like concurrent mode, suspense, and a large ecosystem of tools and libraries. It is designed for building complex and scalable applications with rich interactivity.

Preact is a lightweight alternative that mimics React's API but is much smaller in size, making it ideal for projects where performance and load time are critical. However, it lacks some advanced React features like concurrent mode and has a smaller ecosystem.

While Preact supports hooks and context API, some React-specific features or third-party libraries that rely on React internals may not work perfectly without compatibility layers like preact/compat. This makes Preact a great choice for simpler or performance-sensitive apps, but React remains the go-to for full-featured, large-scale projects.

Code Comparison

Here is a simple React component that shows a counter with a button to increase the count.

javascript

import React, { useState } from 'react';

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

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increase</button>
    </div>
  );
}

Output

Count: 0 (button labeled 'Increase' increments count on click)

Preact Equivalent

The same counter component in Preact looks almost identical, using hooks from Preact.

javascript

import { h } from 'preact';
import { useState } from 'preact/hooks';

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

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increase</button>
    </div>
  );
}

Output

Count: 0 (button labeled 'Increase' increments count on click)

When to Use Which

Choose React when building complex applications that need advanced features, a large ecosystem, and long-term support. React is best for projects requiring concurrent mode, suspense, or extensive third-party integrations.

Choose Preact when you want a very small bundle size and faster load times, especially for simple or performance-critical apps. Preact is ideal for projects where minimal size and speed outweigh the need for full React features.

Key Takeaways

React offers a full-featured UI library with a large ecosystem and advanced features.

Preact is a lightweight, faster alternative with a mostly compatible React API.

Use React for complex, large-scale apps needing rich features and tooling.

Use Preact for small, fast-loading apps where size and speed matter most.

Preact may require compatibility layers for some React libraries or features.