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ConvertBox

Code Beautifier

Format and beautify HTML, CSS, JavaScript, and JSON with adjustable indentation. Free in-browser beautifier — paste messy code, get readable output.

How to Use

  1. Pick the code language from the selector at the top (HTML, CSS, JavaScript, or JSON)
  2. Paste your code into the input area — works for minified bundles, Stack Overflow snippets, or messy Slack pastes
  3. Choose the indentation that matches your team style: 2 spaces (frontend), 4 spaces (Java/Python), or tabs (legacy projects)
  4. Click "Beautify code" — everything runs locally in your browser, not a single line is sent to a server
  5. Copy the result from the right panel to your clipboard with one click, ready to paste into VS Code, IntelliJ, GitHub, or Notion
  6. JSON mode validates syntax automatically and highlights the exact line where the JSON breaks, useful when debugging API responses

All processing is done in your browser, and files are never sent to a server.

Frequently Asked Questions

The beautifier supports HTML, CSS, JavaScript, and JSON code.
Yes, you can adjust indent size and choose between spaces and tabs.
Each code type should be selected individually for the best formatting results.
No. Beautification runs entirely in your browser via Prettier-like libraries — code never leaves the page.
Yes. The beautifier handles minified JS, including obfuscated bundles, though variable names will stay short.
Yes, up to a few MB. Beyond that, browser memory becomes the limit — split very large files first.
Yes — many teams beautify locally to keep PR diffs free of whitespace noise that hides the real change.
No. All operations are processed entirely inside your browser's local sandbox using client-side APIs (like WebAssembly, pdf-lib, or HTML5 Canvas). Your files and data never leave your device.
The tool is completely free with no usage limits. However, since processing occurs in your browser's memory, we recommend keeping file sizes under 50MB (especially for heavy files like PDFs or videos) to ensure stability.
No. All tools on ConvertBox are 100% free. We do not insert watermarks, limit features, or require any registration or payment.

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