Code Prettifier

What Is a Code Prettifier?

A code prettifier (also known as a code beautifier or un-minifier) takes minified, compressed, or messy code and reformats it with proper indentation, line breaks, and spacing to make it human-readable. Minified code is common in production JavaScript bundles, third-party scripts, and vendor libraries where file size optimization strips all formatting. Our free code prettifier handles JavaScript, CSS, and HTML in a single unified tool with auto-language detection, so you do not need to know which specific formatter to use.

How to Use This Code Prettifier

Paste your minified or messy code into the input editor on the left. The tool automatically detects whether it is JavaScript, CSS, or HTML and applies the correct formatting rules. Click "Prettify" to generate the formatted output in the right panel, or enable auto-format for real-time results as you type. Choose your preferred indentation (2 spaces, 4 spaces, or tabs) from the toolbar. You can also drag and drop .js, .css, or .html files directly into the editor.

Key Features

• Auto-detect language — paste any code and the tool identifies JS, CSS, or HTML automatically
• Real-time preview — output updates live as you type or paste (debounced at 300ms)
• Configurable indentation — 2 spaces, 4 spaces, or tabs
• Syntax highlighting — language-aware color coding in both input and output panels
• File upload and download — drag-drop files in, download prettified output with one click
• 100% client-side — code never leaves your browser, safe for proprietary source code

Why Use a Universal Prettifier?

When debugging a minified production bundle, you often encounter JavaScript, CSS, and inline HTML all tangled together in the same file. Instead of switching between separate JS, CSS, and HTML beautifiers, this unified tool handles all three languages in one place. It is especially useful for inspecting third-party scripts, reading minified vendor code, and cleaning up messy output from content management systems and page builders. The tool uses the same js-beautify engine trusted by VS Code, Atom, and Sublime Text plugins.

Common Use Cases

• Frontend developers — un-minifying production JS/CSS bundles for debugging
• Full-stack developers — quickly formatting code snippets from Stack Overflow or ChatGPT
• QA engineers — inspecting minified page source during test runs
• Security researchers — de-obfuscating and reading minified third-party scripts
• Students — understanding minified code examples by expanding them into readable form

Tips and Best Practices

Use 2-space indentation for JavaScript and HTML projects — it is the most common standard in the JavaScript ecosystem and produces compact, readable output. If the auto-detection picks the wrong language, override it manually using the dropdown before prettifying. For very large files, the tool processes in chunks to avoid freezing the browser. After prettifying, use the line count and character count in the status bar to verify the output is complete. If you need the opposite operation (minification), check out our dedicated JavaScript Minifier, CSS Minifier, and HTML Minifier tools for optimized compression.