JavaScript Beautifier & Minifier

How to use this tool

1. Paste JavaScript into the input panel, or open or drop a local .js, .mjs, or .cjs file.
2. Choose "Beautify" to format with indentation, or "Minify" to compress.
3. In Beautify mode, adjust indentation, brace style, wrapping, and newline preservation.
4. Review the output and input-to-output character counts as they update.
5. Copy the result or download a JavaScript file to keep it on your device.

What is JavaScript beautifying?

Minified or machine-generated JavaScript is intentionally hard to read: no indentation, no line breaks, single-character variable names. Beautifying restores consistent indentation, spacing around operators, and line breaks after statements so the code can be reviewed, debugged, or understood.

What is JavaScript minification?

Minification removes comments and collapses whitespace to reduce file size. This tool implements a basic, string-aware minifier suitable for quick transformations. For production builds with dead-code elimination and variable mangling, use a dedicated build tool like terser, esbuild, or your framework's built-in bundler.

When to use each mode

Use Beautify when reading or reviewing unfamiliar code, debugging a minified file, or preparing a code snippet for documentation. Use Minify when you need a quick reduction in file size without setting up a full build pipeline.

Indentation and formatting options

Beautify uses js-beautify in your browser. Choose two spaces, four spaces, or tabs to match a project convention. Brace style controls whether opening braces stay on the statement line, move to the next line, or only closing braces move; wrap length adds line breaks around long expressions. Preserve newlines keeps existing source line breaks where possible. These choices change presentation, not program behavior, and they do not validate syntax.

Linting vs. formatting

These two tools solve different problems:

• Formatters (like Prettier) enforce a consistent code style: indentation, quotes, semicolons, line length. They rewrite code automatically but do not catch logical errors.
• Linters (like ESLint) enforce code quality rules: unused variables, potential bugs, accessibility issues, security patterns. They flag problems but generally do not rewrite code.

In most projects, Prettier handles formatting and ESLint handles everything else. Running Prettier after ESLint ensures consistent style without fighting ESLint's formatting rules.

Minification for production

This tool's minifier is suitable for quick experiments. For production deployments, use a dedicated build tool:

• esbuild: extremely fast, supports tree-shaking and bundling
• terser: battle-tested JS minifier with advanced dead-code elimination and variable mangling
• Rollup / Vite / webpack: full build pipelines with code splitting, tree-shaking, and source maps

Build tools can reduce production bundles by 60–80% compared to the original source through minification combined with tree-shaking.

Privacy

Paste code or open and drop a local .js, .mjs, or .cjs file up to 2 MB. The file is read with the browser's FileReader API and stays on your device; no source is sent to a server. Download creates a new JavaScript file from the current output. This basic minifier handles common strings and comments, but it is not a full JavaScript parser and does not handle every regular-expression or JSX edge case. Review the result, and use a production build tool such as esbuild or Terser for deployment.