HTML Beautifier

Free online HTML beautifier and formatter. Instantly format minified or messy HTML with proper indentation, tag alignment, and attribute organization. Client-side processing — your code never leaves the browser.

HTML Beautifier

🔒 100% Client-Side — Your code never leaves the browser

Quick Examples

⚡ Minified HTML 🔀 Messy Indentation 📐 Semantic Layout 📝 Form Elements

Input HTML

Output

Indent:

Sort Attributes

Remove Comments

Preserve Inline Elements

⚠ Tag Warnings

Total Tags

Unique Elements

Max Depth

Attributes

Input (bytes)

Output (bytes)

⟨/⟩ Tag Breakdown

Size Change

', messy: '\n\n\n Blog Post\n \n\n \n

Understanding Flexbox

\n Jane Doe\n January 15, 2026\n

Flexbox is a powerful CSS layout module that makes it easy to design\n flexible responsive layout structures.

Key Concepts

Flex Container
Flex Items
Main Axis vs Cross Axis
Flex Wrap

\n
Flexbox changed how we think about CSS layouts forever.
\n

Read more about CSS Grid for two-dimensional layouts.

\n \n', semantic: '\n\n\n \n \n Semantic HTML5 Layout\n\n\n \n

Article Title

Published on March 7, 2026

Introduction

This article demonstrates semantic HTML5 elements that improve accessibility and SEO.

HTML5 semantic elements diagram — Semantic elements provide meaning to the document structure.

\n \n \n

\n \n\n', form: 'Registration Form

' }; function hbLoadExample(key) { document.getElementById('htmlInput').value = HB_EXAMPLES[key]; document.getElementById('htmlOutput').value = ''; hbHideStats(); } /* ── Utility Functions ───────────────────── */ function hbClearInput() { document.getElementById('htmlInput').value = ''; document.getElementById('htmlOutput').value = ''; hbHideStats(); } function hbPasteFromClipboard() { navigator.clipboard.readText().then(function(text) { document.getElementById('htmlInput').value = text; }).catch(function() {}); } function hbCopyOutput() { var text = document.getElementById('htmlOutput').value; if (!text) return; var btn = document.getElementById('hbCopyBtn'); navigator.clipboard.writeText(text).then(function() { btn.classList.add('copied'); btn.textContent = '✓ Copied'; setTimeout(function() { btn.classList.remove('copied'); btn.textContent = '\u29C9 Copy'; }, 1500); }).catch(function() {}); } function hbDownloadOutput() { var code = document.getElementById('htmlOutput').value; if (!code) return; var blob = new Blob([code], { type: 'text/html' }); var a = document.createElement('a'); a.href = URL.createObjectURL(blob); a.download = 'beautified.html'; a.click(); URL.revokeObjectURL(a.href); } function hbHideStats() { document.getElementById('hbStatsRibbon').classList.remove('visible'); document.getElementById('hbTagBreakdown').classList.remove('visible'); document.getElementById('hbDiffBar').classList.remove('visible'); document.getElementById('hbWarnings').classList.remove('visible'); } /* ── HTML Element Classifications ─────────── */ var VOID_ELEMENTS = ['area','base','br','col','embed','hr','img','input','link','meta','param','source','track','wbr']; var INLINE_ELEMENTS = ['a','abbr','acronym','b','bdo','big','br','button','cite','code','dfn','em','i','img','input','kbd','label','map','object','output','q','samp','select','small','span','strong','sub','sup','textarea','time','tt','u','var']; var RAW_TEXT_ELEMENTS = ['script','style']; var PRESERVE_ELEMENTS = ['pre','code','textarea','script','style']; /* ── HTML Beautifier Engine ──────────────── */ function hbTokenize(html) { var tokens = []; var i = 0; var len = html.length; while (i < len) { // Comment if (html.substr(i, 4) === '', i + 4); if (end === -1) end = len - 3; tokens.push({ type: 'comment', value: html.substring(i, end + 3) }); i = end + 3; } // DOCTYPE else if (html.substr(i, 9).toUpperCase() === '', i); if (end === -1) end = len - 1; tokens.push({ type: 'doctype', value: html.substring(i, end + 1) }); i = end + 1; } // CDATA else if (html.substr(i, 9) === '', i + 9); if (end === -1) end = len - 3; tokens.push({ type: 'cdata', value: html.substring(i, end + 3) }); i = end + 3; } // Closing tag else if (html.substr(i, 2) === '', i); if (end === -1) end = len - 1; var tag = html.substring(i + 2, end).trim().toLowerCase(); tokens.push({ type: 'close', tag: tag, value: html.substring(i, end + 1) }); i = end + 1; } // Opening tag else if (html[i] === '<' && i + 1 < len && /[a-zA-Z]/.test(html[i + 1])) { var end = i + 1; var inQuote = false; var quoteChar = ''; while (end < len) { var ch = html[end]; if (inQuote) { if (ch === quoteChar) inQuote = false; } else { if (ch === '"' || ch === "'") { inQuote = true; quoteChar = ch; } else if (ch === '>') break; } end++; } if (end >= len) end = len - 1; var tagContent = html.substring(i + 1, end); var selfClosing = tagContent.charAt(tagContent.length - 1) === '/'; if (selfClosing) tagContent = tagContent.substring(0, tagContent.length - 1); // Parse tag name and attributes var spaceIdx = tagContent.search(/[\s\/]/); var tagName, attrStr; if (spaceIdx === -1) { tagName = tagContent.trim(); attrStr = ''; } else { tagName = tagContent.substring(0, spaceIdx).trim(); attrStr = tagContent.substring(spaceIdx).trim(); } tagName = tagName.toLowerCase(); var isVoid = VOID_ELEMENTS.indexOf(tagName) !== -1; // Parse attributes var attrs = hbParseAttributes(attrStr); tokens.push({ type: 'open', tag: tagName, attrs: attrs, selfClosing: selfClosing || isVoid, isVoid: isVoid, raw: html.substring(i, end + 1) }); i = end + 1; // Handle raw text elements (script, style) if (RAW_TEXT_ELEMENTS.indexOf(tagName) !== -1 && !selfClosing && !isVoid) { var closeTag = ''); return parts.join(''); } function hbBeautifyCode(html, opts) { var indent = opts.indent || ' '; var sortAttrs = opts.sortAttrs || false; var removeComments = opts.removeComments || false; var preserveInline = opts.preserveInline !== false; var tokens = hbTokenize(html); var output = []; var level = 0; var preserveStack = 0; function addIndent(d) { var r = ''; for (var j = 0; j < d; j++) r += indent; return r; } function isInline(tagName) { return preserveInline && INLINE_ELEMENTS.indexOf(tagName) !== -1; } function isPreserve(tagName) { return PRESERVE_ELEMENTS.indexOf(tagName) !== -1; } for (var i = 0; i < tokens.length; i++) { var token = tokens[i]; if (token.type === 'comment') { if (!removeComments) { if (preserveStack > 0) { output.push(token.value); } else { output.push(addIndent(level) + token.value); } } } else if (token.type === 'doctype') { output.push(token.value); } else if (token.type === 'cdata') { output.push(addIndent(level) + token.value); } else if (token.type === 'open') { var tag = hbBuildTag(token.tag, token.attrs, token.selfClosing, sortAttrs); if (preserveStack > 0) { output.push(tag); if (isPreserve(token.tag) && !token.selfClosing) preserveStack++; } else if (isInline(token.tag)) { // Check if previous output ends with text on the same line if (output.length > 0) { var last = output[output.length - 1]; // If last line has text content, append inline tag to same line var lastNewline = last.lastIndexOf('\n'); var lastLine = lastNewline === -1 ? last : last.substring(lastNewline + 1); if (lastLine.trim() && !lastLine.trim().match(/^<\/(div|section|article|main|header|footer|nav|aside|ul|ol|li|table|tr|td|th|thead|tbody|tfoot|form|fieldset|dl|dt|dd|details|summary|figure|figcaption|blockquote|p|h[1-6]|pre|hr)>/i)) { output[output.length - 1] = last + tag; } else { output.push(addIndent(level) + tag); } } else { output.push(addIndent(level) + tag); } if (!token.selfClosing) { // Don't increase indent for inline elements } } else { output.push(addIndent(level) + tag); if (!token.selfClosing) { if (isPreserve(token.tag)) preserveStack++; level++; } } } else if (token.type === 'close') { if (preserveStack > 0) { if (isPreserve(token.tag)) preserveStack--; output.push(''); } else if (isInline(token.tag)) { // Append closing inline tag to previous line if (output.length > 0) { output[output.length - 1] = output[output.length - 1] + ''; } else { output.push(''); } } else { level--; if (level < 0) level = 0; output.push(addIndent(level) + ''); } } else if (token.type === 'text') { if (preserveStack > 0 || token.preserve) { output.push(token.value); } else { var text = token.value; // Collapse whitespace for non-preserve context var trimmed = text.replace(/\s+/g, ' ').trim(); if (trimmed) { // Check if adjacent to inline elements var prevToken = i > 0 ? tokens[i - 1] : null; var nextToken = i < tokens.length - 1 ? tokens[i + 1] : null; var prevIsInline = prevToken && ((prevToken.type === 'open' && isInline(prevToken.tag)) || (prevToken.type === 'close' && isInline(prevToken.tag))); var nextIsInline = nextToken && ((nextToken.type === 'open' && isInline(nextToken.tag)) || (nextToken.type === 'close' && isInline(nextToken.tag))); if (prevIsInline || nextIsInline) { // Append to previous line for inline continuity if (output.length > 0) { output[output.length - 1] = output[output.length - 1] + trimmed; } else { output.push(trimmed); } } else { output.push(addIndent(level) + trimmed); } } } } } var result = output.join('\n'); // Clean up multiple blank lines result = result.replace(/\n{3,}/g, '\n\n'); return result.trim(); } function hbMinifyCode(html) { // Remove comments html = html.replace(//g, ''); // Collapse whitespace between tags html = html.replace(/>\s+<'); // Collapse internal whitespace html = html.replace(/\s+/g, ' '); // Trim return html.trim(); } /* ── Stats Calculation ───────────────────── */ function hbGetStats(html) { var stats = { totalTags: 0, uniqueTags: {}, maxDepth: 0, attrCount: 0, warnings: [], tagTypes: { block: {}, inline: {}, void_el: {}, semantic: {} } }; var SEMANTIC = ['article','aside','details','figcaption','figure','footer','header','main','mark','nav','section','summary','time']; var BLOCK = ['div','p','h1','h2','h3','h4','h5','h6','ul','ol','li','table','tr','td','th','thead','tbody','tfoot','form','fieldset','legend','blockquote','pre','dl','dt','dd','hr']; var tokens = hbTokenize(html); var stack = []; var depth = 0; for (var i = 0; i < tokens.length; i++) { var t = tokens[i]; if (t.type === 'open') { stats.totalTags++; stats.uniqueTags[t.tag] = (stats.uniqueTags[t.tag] || 0) + 1; if (t.attrs) stats.attrCount += t.attrs.length; // Classify tag if (SEMANTIC.indexOf(t.tag) !== -1) { stats.tagTypes.semantic[t.tag] = (stats.tagTypes.semantic[t.tag] || 0) + 1; } else if (VOID_ELEMENTS.indexOf(t.tag) !== -1) { stats.tagTypes.void_el[t.tag] = (stats.tagTypes.void_el[t.tag] || 0) + 1; } else if (INLINE_ELEMENTS.indexOf(t.tag) !== -1) { stats.tagTypes.inline[t.tag] = (stats.tagTypes.inline[t.tag] || 0) + 1; } else if (BLOCK.indexOf(t.tag) !== -1 || t.tag === 'html' || t.tag === 'head' || t.tag === 'body') { stats.tagTypes.block[t.tag] = (stats.tagTypes.block[t.tag] || 0) + 1; } else { stats.tagTypes.block[t.tag] = (stats.tagTypes.block[t.tag] || 0) + 1; } if (!t.selfClosing) { stack.push(t.tag); depth = stack.length; if (depth > stats.maxDepth) stats.maxDepth = depth; } } else if (t.type === 'close') { stats.totalTags++; // Find matching open tag var found = false; for (var j = stack.length - 1; j >= 0; j--) { if (stack[j] === t.tag) { // Warn about any unclosed tags above this for (var k = stack.length - 1; k > j; k--) { stats.warnings.push('Unclosed <' + stack[k] + '> tag'); } stack.splice(j); found = true; break; } } if (!found) { stats.warnings.push('Unexpected closing tag'); } } } // Any remaining tags on stack are unclosed for (var s = 0; s < stack.length; s++) { stats.warnings.push('Unclosed <' + stack[s] + '> tag'); } return stats; } /* ── Display Functions ───────────────────── */ function hbShowStats(inputHtml, outputHtml) { var stats = hbGetStats(inputHtml); var inputSize = new Blob([inputHtml]).size; var outputSize = new Blob([outputHtml]).size; document.getElementById('hbStatTags').textContent = stats.totalTags; document.getElementById('hbStatUnique').textContent = Object.keys(stats.uniqueTags).length; document.getElementById('hbStatDepth').textContent = stats.maxDepth; document.getElementById('hbStatAttrs').textContent = stats.attrCount; document.getElementById('hbStatInputSize').textContent = hbFormatSize(inputSize); document.getElementById('hbStatOutputSize').textContent = hbFormatSize(outputSize); document.getElementById('hbStatsRibbon').classList.add('visible'); // Tag breakdown var grid = document.getElementById('hbTagGrid'); grid.innerHTML = ''; var types = [ { obj: stats.tagTypes.semantic, cls: 'tag-pill-semantic', label: 'semantic' }, { obj: stats.tagTypes.block, cls: 'tag-pill-block', label: 'block' }, { obj: stats.tagTypes.inline, cls: 'tag-pill-inline', label: 'inline' }, { obj: stats.tagTypes.void_el, cls: 'tag-pill-void', label: 'void' } ]; var hasAny = false; for (var t = 0; t < types.length; t++) { var keys = Object.keys(types[t].obj).sort(); for (var k = 0; k < keys.length; k++) { hasAny = true; var pill = document.createElement('span'); pill.className = 'tag-pill ' + types[t].cls; pill.innerHTML = '<' + keys[k] + '> ' + types[t].obj[keys[k]] + ''; grid.appendChild(pill); } } if (hasAny) { document.getElementById('hbTagBreakdown').classList.add('visible'); } // Warnings if (stats.warnings.length > 0) { var list = document.getElementById('hbWarningsList'); list.innerHTML = ''; // Deduplicate var unique = []; var seen = {}; for (var w = 0; w < stats.warnings.length; w++) { if (!seen[stats.warnings[w]]) { seen[stats.warnings[w]] = true; unique.push(stats.warnings[w]); } } for (var u = 0; u < unique.length && u < 10; u++) { var li = document.createElement('li'); li.textContent = unique[u]; list.appendChild(li); } document.getElementById('hbWarnings').classList.add('visible'); } // Diff bar var pct, isShrink; if (inputSize === 0) { pct = 0; isShrink = true; } else { var change = ((outputSize - inputSize) / inputSize) * 100; isShrink = change < 0; pct = Math.abs(change); } var fill = document.getElementById('hbDiffFill'); var cappedPct = Math.min(pct, 100); fill.style.width = cappedPct + '%'; fill.className = 'diff-fill ' + (isShrink ? 'shrink' : 'grow'); document.getElementById('hbDiffValue').textContent = (isShrink ? '-' : '+') + pct.toFixed(1) + '%'; document.getElementById('hbDiffBar').classList.add('visible'); } function hbFormatSize(bytes) { if (bytes < 1024) return bytes + ''; return (bytes / 1024).toFixed(1) + 'K'; } /* ── Main Actions ────────────────────────── */ function hbBeautify() { var input = document.getElementById('htmlInput').value; if (!input.trim()) return; var indentSel = document.getElementById('hbIndentSize').value; var indent; if (indentSel === 'tab') indent = '\t'; else indent = new Array(parseInt(indentSel) + 1).join(' '); var opts = { indent: indent, sortAttrs: document.getElementById('hbOptSortAttrs').checked, removeComments: document.getElementById('hbOptRemoveComments').checked, preserveInline: document.getElementById('hbOptPreserveInline').checked }; var output = hbBeautifyCode(input, opts); document.getElementById('htmlOutput').value = output; hbShowStats(input, output); } function hbMinify() { var input = document.getElementById('htmlInput').value; if (!input.trim()) return; var output = hbMinifyCode(input); document.getElementById('htmlOutput').value = output; hbShowStats(input, output); }

Embed HTML Beautifier Widget

About HTML Beautifier

The HTML Beautifier is a free online tool that instantly reformats messy, minified, or poorly structured HTML into clean, well-indented code. Whether you need to debug production markup, review someone else's code, or simply tidy up a sprawling template, this tool handles it in one click. All processing happens in your browser — your code never touches a server.

How to Use the HTML Beautifier

Paste your HTML code into the input editor on the left, or click one of the quick example buttons to load sample code.
Configure your preferences using the options bar: choose indent size (2 spaces, 4 spaces, or tab), toggle attribute sorting, comment removal, or inline element preservation.
Click "Beautify HTML" to instantly format your code. The output appears in the right panel.
Review the stats ribbon to see tag counts, nesting depth, element breakdown, and any tag warnings.
Copy or download the result using the buttons in the output panel header.

Key Features

✦

Smart Indentation

Properly indents nested tags while respecting inline elements like <span>, <strong>, and <a> that should stay on the same line as surrounding text.

⟨/⟩

Tag-Aware Formatting

Distinguishes block elements (div, section), inline elements (span, em), void elements (br, img, input), and semantic elements (header, nav, article) for context-appropriate formatting.

⚠

Error Detection

Detects unclosed tags and mismatched nesting after formatting, helping you catch common HTML bugs before they cause rendering issues in browsers.

◁▷

Minify Mode

One-click minification strips all unnecessary whitespace and comments from HTML, reducing file size for faster page loads in production.

📊

Live Statistics

Instant analytics showing total tags, unique elements, max nesting depth, attribute count, input/output size, and a visual tag-type breakdown.

🔒

100% Client-Side

All processing happens in your browser. Your HTML is never uploaded, stored, or transmitted to any server. Complete privacy guaranteed.

When to Beautify HTML

Debugging Production Code

Minified HTML is nearly impossible to read. When you need to inspect page structure, track down a layout bug, or understand how a CMS renders its output, paste the minified source here to expand it into readable, indented markup.

Code Reviews

Consistent formatting makes pull requests easier to review. Beautify HTML before reviewing to ensure everyone sees the same clean structure, making differences in logic stand out rather than differences in formatting.

Learning HTML Structure

If you are learning HTML or teaching someone, well-formatted code is essential. Proper indentation reveals the parent-child relationship between elements, making the document tree structure visually obvious.

Cleaning Up Generated Markup

WYSIWYG editors, email builders, and CMS platforms often produce messy HTML with inconsistent indentation and unnecessary attributes. Use this tool to clean it up before manual editing.

Beautify vs. Minify HTML

Aspect	Beautify	Minify
Purpose	Readability during development	Smaller file size for production
Whitespace	Adds indentation and line breaks	Removes all unnecessary whitespace
Comments	Preserved (optional removal)	Removed
Best for	Debugging, reviews, learning	Deployment, page speed

HTML Formatting Best Practices

Use consistent indentation — Pick 2 spaces, 4 spaces, or tabs and maintain it across your entire project for clean diffs in version control.
One block element per line — Each block-level element should start on its own line to make the document structure clear.
Keep inline elements inline — Elements like <strong>, <em>, and <a> should remain on the same line as surrounding text to preserve readability.
Sort attributes consistently — Alphabetical attribute ordering helps teams find attributes quickly and prevents duplicates. Common conventions put id first, then class, then alphabetical.
Use semantic elements — Prefer <header>, <nav>, <main>, <article>, and <footer> over generic <div> elements for accessibility and SEO.

Frequently Asked Questions

What is an HTML Beautifier?

An HTML Beautifier is an online tool that reformats messy, minified, or poorly indented HTML code into a clean, readable format with proper indentation, consistent tag alignment, and organized attribute layout. It makes HTML easier to read, edit, debug, and maintain.

Is my HTML code safe when using this tool?

Yes, completely safe. All HTML formatting happens entirely in your browser using client-side JavaScript. Your code is never sent to any server, stored, or transmitted anywhere. Your HTML remains completely private.

What is the difference between beautifying and minifying HTML?

Beautifying expands HTML into a readable format with proper indentation and line breaks, ideal for development and debugging. Minifying removes all unnecessary whitespace, comments, and line breaks to reduce file size, ideal for production deployment and faster page loading.

Does this tool handle inline elements like span and strong correctly?

Yes. The beautifier distinguishes between block-level elements (div, section, article) and inline elements (span, strong, em, a). Inline elements within text content are kept on the same line to preserve natural reading flow, while block elements get their own indented lines.

Can this tool detect HTML errors like unclosed tags?

Yes. After beautifying, the stats panel shows tag analysis including any unclosed tags or mismatched nesting. This helps you catch common HTML errors that could cause rendering issues in browsers.

Related Resources

Reference this content, page, or tool as:

"HTML Beautifier" at https://MiniWebtool.com/html-beautifier/ from MiniWebtool, https://MiniWebtool.com/

by miniwebtool team. Updated: 2026-03-07

Developer API available: Run this tool from your app, automation, or agent with one JSON HTTP request. View API docs

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HTML Beautifier

Understanding Flexbox

Key Concepts

Introduction

About HTML Beautifier

How to Use the HTML Beautifier

Key Features

Smart Indentation

Tag-Aware Formatting

Error Detection

Minify Mode

Live Statistics

100% Client-Side

When to Beautify HTML

Debugging Production Code

Code Reviews

Learning HTML Structure

Cleaning Up Generated Markup

Beautify vs. Minify HTML

HTML Formatting Best Practices

Frequently Asked Questions

What is an HTML Beautifier?

Is my HTML code safe when using this tool?

What is the difference between beautifying and minifying HTML?

Does this tool handle inline elements like span and strong correctly?

Can this tool detect HTML errors like unclosed tags?

Related Resources

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