Articles · Developer Tools
Beautify JavaScript and HTML without running them
A minified bundle or a one-line HTML email is painful to read. A formatter that indents braces and tags on this device is enough for a review or a fixture. It does not need to compile C# or Java, and it must not eval the JavaScript you pasted. HTML preview is a separate, sandboxed iframe with scripts disabled—not innerHTML on the tool page. JSON, XML, and YAML already have dedicated engines; this page delegates to them instead of inventing a fourth parser.
Why this is worth doing in the browser
The DevNestro Code Formatter & Beautifier lists only languages it actually implements: JavaScript, TypeScript, HTML, CSS, SCSS indent (not Sass compilation), Markdown spacing, GraphQL indent (not schema validation), JSON, XML, and YAML. C# and Java are omitted because shipping a compiler would be theater. There is no Prettier or Biome bundle loaded for every visitor; formatting is a local indent engine. Paste or upload up to 5 MB; oversized files are rejected, not truncated. Minify is available where the language supports it. javascript-formatter, typescript-formatter, html-formatter, css-formatter, xml-formatter, yaml-formatter, and graphql-formatter share this page. Analytics may record that you formatted, never the source.
How to use the tool
Choose a listed language, paste or upload, format, then copy or download. Preview HTML only when you need a layout check; scripts stay off. Use the JSON, XML, or YAML tools when you want trees, XPath, or duplicate-key warnings.
- Pick the real language; TypeScript is indented like JavaScript, not type-checked.
- Do not expect Sass compilation from SCSS mode—only nested-brace indent.
- Treat GraphQL output as pretty queries, not as a valid schema.
- Use the sandboxed preview, never paste untrusted HTML into another tab’s console.
- Stay under the 5 MB limit; large files are refused rather than chopped.
Privacy
Formatting and HTML preview run in the current browser. Source is not uploaded to DevNestro, not sent to an external formatter API, and not sent to analytics. There is no paid API and no account.
Need readable JavaScript or HTML without executing it? Open the Code Formatter, indent locally, and keep the preview sandboxed.