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How do I minify or beautify JavaScript, CSS, or HTML online?

Paste your code, select the language (JavaScript, CSS, or HTML), and click Minify to strip whitespace and reduce file size, or click Beautify to format it with clean indentation. The tool shows the size reduction percentage. Everything runs in your browser — your code never leaves your device.

Minify JavaScript
Input
function greet(name) {
  const message = "Hello, " + name;
  console.log(message);
  return message;
}
Output
function greet(n){const m="Hello, "+n;console.log(m);return m}
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Code Minifier & Beautifier

Minify or beautify JavaScript, CSS, and HTML code instantly. No data leaves your browser.

About Code Minification & Beautification

Beautify reformats your code with proper indentation, line breaks, and spacing for maximum readability. Great for reading minified production code or cleaning up messy formatting.

Minify removes all unnecessary whitespace, comments, and formatting to produce the smallest possible output. Minified code loads faster and uses less bandwidth — essential for production deployments.

JavaScript: Handles string literals (single, double, template), comments (single-line and multi-line), regex literals, and all modern syntax. Preserves semicolons and statement structure.

CSS: Handles selectors, declarations, at-rules (@media, @keyframes), comments, and nested structures. Collapses whitespace around delimiters for maximum compression.

HTML: Handles all standard tags, void elements (br, img, input, etc.), comments, DOCTYPE declarations, and embedded script/style content. Preserves content within pre and textarea tags.

Tips & Best Practices

Pro Tip

Enable source maps alongside minification for debugging

Minification replaces variable names with single characters, making stack traces unreadable. Source maps (.map files) map minified code back to original source. Configure your bundler to generate source maps and upload them to your error tracking service (Sentry, Datadog). Never serve source maps publicly in production.

Common Pitfall

CSS minification can break specificity in rare cases

Some aggressive CSS minifiers merge selectors or reorder declarations. If your CSS relies on source order for specificity tie-breaking (two selectors with equal specificity), reordering changes which rule wins. Use explicit specificity (more specific selectors or layers) rather than relying on source order.

Real-World Example

Gzip/Brotli compression after minification gives 80-90% reduction

Minification alone typically reduces JavaScript by 30-50%. But Gzip or Brotli compression on the minified output achieves 80-90% total reduction. Enable both: minify during build (removes dead code, shortens names) and compress during transfer (HTTP Content-Encoding). They're complementary, not alternatives.

Security Note

Minification is not obfuscation

Minified code is smaller but not secret. Variable shortening is trivially reversed with a beautifier. If you need to protect client-side logic (license checks, API keys), move it to the server. No client-side technique — including obfuscation — prevents a determined attacker from reading your JavaScript.

Frequently Asked Questions

What does minifying code do?
Minifying removes all unnecessary characters from source code without changing its functionality. This includes whitespace, line breaks, comments, and in the case of JavaScript, shortening variable names. For CSS, it also merges duplicate selectors and shorthand properties. Minification typically reduces JavaScript file size by 40-60% and CSS by 20-40%. Smaller files download faster, reducing page load time and bandwidth costs. Most build tools (webpack, Vite, esbuild) minify automatically for production builds. DevBolt's minifier handles JavaScript, CSS, and HTML with instant results and no server upload.
What is the difference between minifying and beautifying code?
Minifying compresses code by removing all non-essential whitespace, comments, and formatting to produce the smallest possible file. Beautifying (also called prettifying or formatting) does the opposite — it adds consistent indentation, line breaks, and spacing to make code human-readable. Minified code is for production deployment where file size matters. Beautified code is for development where readability matters. You might beautify minified code to debug a production issue, or minify your source code for deployment. Both operations are reversible and do not change the code's behavior.
Should I minify HTML?
HTML minification provides smaller gains than JavaScript or CSS minification — typically 10-20% size reduction. The benefit depends on how much whitespace and comments your HTML contains. For server-rendered pages with lots of template comments and indentation, minification helps. For SPAs where HTML is minimal and JavaScript is the main payload, the benefit is negligible. Modern HTTP compression (Brotli/Gzip) already eliminates most whitespace redundancy during transfer. Focus on minifying JavaScript and CSS first. HTML minification is a micro-optimization worth doing only after addressing larger performance bottlenecks.

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