Free online HTML beautify, minify, validate, DOM tree view, tag path extraction and statistics. Help frontend developers quickly parse, organize and beautify HTML code.
Beautify HTML with one click. Supports 2/4 spaces and Tab indentation. Follows W3C conventions for attribute ordering and tag alignment.
Strips whitespace, comments and redundant attributes. Configurable options to reduce file size and speed up page loads.
Detects unclosed tags, invalid nesting, duplicate IDs and missing DOCTYPE with precise line/column location hints.
Collapsible node tree visualizes HTML document structure at a glance. Click any node to extract its full tag path.
Real-time stats display: line count, tag count, attribute count, unique tag kinds, character count, and file size.
All parsing, formatting and validation happens inside your browser. Code is never uploaded to protect frontend source privacy.
Paste messy HTML code into the left-hand input, or click the "Sample" button to load a full HTML5 demo template and see how the tool works.
Pick the indentation style (2 spaces / 4 spaces / Tab) and toggle the options like Remove comments, Remove blank attributes, Keep self-closing slash.
Click "Format" for a beautified structured output, or click "Minify" to collapse whitespace and shrink file size. By default formatting is applied automatically as you type — toggle it off in options if you don't need it.
Switch to "Tree View" to browse the collapsible DOM structure. Click any tag row to view and copy its full tag path (e.g. html > body > main > div.card).
Receive compressed or unfamiliar legacy HTML? Format it instantly to restore readability and simplify team collaboration.
Format deeply nested HTML email table templates so you can see hierarchy and style attributes at a glance.
Format scraper raw HTML fragments to understand tag structure and write reliable regex extractors.
Clean up messy HTML exported from CMS rich-text editors; verify tag closure and sort attribute order.
Tree view visualizes the real DOM tree, great for teaching tag nesting and semantic HTML concepts to beginners.
Minify static HTML before deploy to reduce page load time, boost SEO first-paint speed and improve UX.
HTML (HyperText Markup Language) is the standard markup language for building web page skeletons. It describes page structure with tags, attributes and text nodes. HTML5 introduced semantic tags, native multimedia support and 2D canvas, becoming the foundation of the modern Web when combined with CSS styling and JavaScript logic.
HTML5 adds semantic tags: header, nav, main, article, section, footer; native support for video, audio and canvas; drops strict XHTML self-closing slash requirements (no more need for img/); adds new input types like date, range and email along with built-in validation; and deprecates purely presentational tags like font, center and frame.
Semantic tags describe the meaning of content instead of using generic div everywhere: header for page header, article for standalone content, section for a chapter, nav for navigation, aside for sidebar, footer for footer. Benefits include far better team code readability, clearer structure for SEO crawlers to assign ranking weight, and reliable document structure descriptions for screen readers used by visually impaired users.
The !DOCTYPE html declaration must go on line 1 of the HTML document. It instructs the browser to render the page in HTML5 Standards Mode. When DOCTYPE is missing, Internet Explorer and some modern browsers fall into Quirks Mode — which uses legacy box-model sizing, different default font metrics and layout offsets, causing subtle but confusing rendering bugs.
Readable HTML directly improves team collaboration and long-term maintainability. This HTML beautifier follows the industry-standard practices summarized below:
<div>
<p>Children are indented
2 spaces vs parent
</p>
</div>Each nested child element is indented one extra level relative to its parent. Pick 2 or 4 spaces and stick to the same project-wide convention — never mix tabs and spaces or editors will display the code inconsistently.
<!-- Recommended -->
<div class="card">Hello</div>
<!-- Avoid -->
<DIV CLASS="CARD">Hello</DIV>Always write HTML tag names and attribute names in lowercase. Although HTML5 doesn't force it, lowercase is the universal industry style and matches how CSS selectors and JavaScript APIs reference elements.
<a class="btn"
id="submitBtn"
data-id="1001"
href="/submit"
type="button"
aria-label="Submit form">Recommended order: class → id → name → data-* → src/href → type → value → event handlers → aria-*. Keeping commonly used attributes first boosts readability and produces friendlier version-control diffs.
<!-- Always double quotes -->
<input type="text" name="user">Wrap all attribute values in double quotes. Generally never drop the quotes (except for true boolean attributes). This is consistent with JSON quoting conventions and reduces cognitive friction when switching between languages.
<!-- HTML5 style -->
<br> <img src="a.png">
<!-- XHTML style -->
<br/> <img src="a.png"/>HTML5 void elements — img, br, hr, input, meta, link and others — allow omitting the trailing slash. Pick one team style and stay consistent. This tool exposes a "Keep self-closing slash" option so you can enforce either standard.
<!-- Header nav area: START -->
<header>...</header>
<!-- Header nav area: END -->Use comments to mark module boundaries or explain tricky logic — avoid redundant line-by-line remarks. During production minification, comments are stripped by default to reduce file size; keep critical architectural notes in your version control commit messages.