Beautify and format HTML5 source code • Clean up messy or minified markup instantly
System Definition BlockBeautify, format, and indent your HTML code instantly. Clean up messy source code for better readability, W3C compliance, and SEO-friendly markup.
WebToolkit Pro is engineered for zero-trust environments. This utility processes your sensitive data entirely within your browser using Web Workers.
The tool utilizes the industry-standard `js-beautify` parsing engine, running entirely client-side via a Web Worker. It tokenizes your raw string into an abstract syntax tree, intelligently recognizing the relationships between block-level elements (like `<div>` or `<section>`) and inline elements (like `<span>` or `<a>`). It then recursively applies strict indentation rules, line breaks, and attribute wrapping to generate a pristine output.
// Prettier can be executed programmatically or via CLI to format HTML
const prettier = require("prettier");
async function formatHTML(rawHtml) {
return await prettier.format(rawHtml, { parser: "html" });
}Technically, yes. Adding spaces and line breaks increases the file size of the HTML document by a few kilobytes. However, for development and debugging, readability is vastly more important. Before deploying to production, you should use an HTML Minifier to strip the spaces back out for maximum speed.
HTML, CSS, and JavaScript have completely different syntactic rules. While our tool attempts to format embedded `<style>` and `<script>` tags, complex JavaScript logic inside an HTML file can sometimes be misaligned. It is always best practice to separate your CSS and JS into external files.
No. A beautifier is not a validator. If you are missing a closing `</div>` tag, the beautifier will format the code based on the assumption that the tag is still open, which often results in unexpected indentation cascading down the rest of the file. This makes finding the missing tag much easier, however.
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