Zero Snippet

HTML formatter & minifier — beautify markup, shrink file size, preview in the browser

Use this free HTML beautifier to pretty-print templates, landing pages, and email markup with clear indentation, or switch to HTML minification to strip comments and collapse whitespace for smaller payloads. Everything runs locally in your browser, and a sandboxed preview helps you compare raw HTML markup with how it renders—ideal for quick cleanup before CMS paste, static site tweaks, and hand-authored semantic HTML reviews.

Rendered preview

Sandboxed iframe: scripts do not run. Compare structure and inline styles with your markup above.

Why use an online HTML formatter?

Messy markup slows down reviews: inconsistent indentation hides nesting mistakes, duplicate wrappers, and forgotten closing tags. An HTML formatter online gives you a predictable layout so diffs in Git stay readable and juniors can follow structure faster. Pair formatting with our XML formatter & validator when you work with XHTML-style documents or feeds that still expect well-formed trees.

When you ship pages rather than snippets, a companion CSS formatter & minifier and JavaScript formatter & minifier keeps assets consistent: readable in source control, compact over the wire after you run your usual build pipeline.

HTML minifier vs beautifier — when to use each

Beautify (pretty-print) is for humans: code review, teaching, and debugging nested components. Minify targets bytes: fewer line breaks and spaces can shrink HTML fragments you embed in APIs, emails, or cached partials. This tool avoids aggressive semantic changes—no automatic class renaming—so you stay in control. For structured data you author by hand, also keep our JSON formatter & validator nearby when you mix JSON-LD with your page head.

How to use this HTML formatter (step by step)

  1. Paste your source into Input HTML. You can drop a full document that starts with <!DOCTYPE html> or a fragment such as a hero section or table row.
  2. Choose an indent width (two spaces, four spaces, or tab) for beautify runs.
  3. Click Beautify for indented output, or Minify to remove HTML comments and extra whitespace outside preserved tags like pre, script, style, and textarea.
  4. Use Copy output to grab the transformed markup. Enable Show preview to open a sandboxed iframe that renders the latest result (or your input before the first run) without executing scripts.

HTML formatting for SEO-friendly templates

Search engines care about discoverable content, fast loads, and valid signals—not tab width—but clean markup makes it easier to audit heading hierarchy, canonical links, and structured data blocks before publish. After you tidy HTML, validate live URLs with our meta tags extractor and canonical tag checker so title, description, and duplication controls still match what you intended.

Converting between HTML and Markdown

Documentation and README files often live in Markdown while sites consume HTML. When you need to migrate prose, use the HTML to Markdown converter for cleanup, and the Markdown to HTML converter when authors write in Markdown but your pipeline expects markup. Run this formatter afterward if you want consistent indentation in stored templates.

Limitations to keep in mind

Browsers follow the HTML parsing algorithm: they repair broken tags and may reorder elements compared with your original bytes. That is expected and matches what visitors experience. The preview iframe uses an empty sandbox attribute so JavaScript inside your snippet does not execute—enable scripts only in your own environment when you trust the source.

Related developer tools

Explore the full code & developer tools section on the home page, or jump to a focused utility below.

  • JSON Formatter & Validator — Format, validate, minify, and explore JSON in a collapsible tree—fix payloads before they hit production.
  • JSON to CSV Converter — Turn JSON arrays into downloadable CSV with automatic column detection for spreadsheets and BI tools.
  • JSON to YAML Converter — Convert JSON to readable YAML for configs and Kubernetes—copy or download the result.
  • CSV to JSON Converter — Paste or upload CSV and get structured JSON with header-aware typing for APIs and apps.
  • YAML to JSON Converter — Parse YAML to valid JSON with clear errors—ideal for CI configs and cloud templates.
  • XML Formatter & Validator — Beautify and validate XML with structure insight and actionable parse errors.
  • Regex Tester & Debugger — Test patterns live with highlights, capture groups, and flags—debug regex without leaving the browser.
  • SQL Formatter — Pretty-print SQL with indentation and keyword casing for readable queries and code review.
  • CSS Formatter & Minifier — Format messy stylesheets or minify CSS for faster loads—keep design tokens consistent.
  • JavaScript Formatter & Minifier — Pretty-print or minify JavaScript for debugging locally and shipping smaller bundles.
  • HTML to Markdown Converter — Convert HTML snippets to Markdown for docs, CMS migrations, and README cleanup.
  • Markdown to HTML Converter — Turn Markdown into HTML with a live preview—handy for emails, blogs, and static pages.
  • Code Diff Checker — Compare two code blocks side by side with clear add/remove highlighting for reviews.
  • JWT Decoder — Decode JWT header and payload and check expiry—signature verification not included, client-side safe.

Frequently asked questions

What does this HTML formatter and minifier do?
Paste HTML markup to beautify it with consistent indentation for reading and code review, or minify it by stripping extra whitespace and HTML comments while keeping content inside pre, script, style, and textarea intact. A sandboxed preview shows how the browser renders your output without running scripts.
Is my HTML sent to a server?
No. Formatting, minification, and preview all run in your browser using the DOMParser API. Nothing is uploaded for this step, which makes it suitable for snippets and templates you prefer to keep local.
Will formatting change my document structure?
The browser parser may normalize malformed markup (for example by closing tags or moving elements per HTML parsing rules). That is the same behavior you get when a page loads in a browser. Treat the tool as a helper for readable output, not a guaranteed byte-preserving pretty printer for invalid HTML.
How is minification different from a production CDN minifier?
This minifier removes comments and collapses whitespace between tags and in text nodes, with exceptions for preserved elements. It does not rename classes, shorten attributes, or apply advanced tree-shaking. For production builds, keep using your bundler or a dedicated HTML pipeline.
Why does the preview look different from my editor?
The preview uses a sandboxed iframe with scripts disabled for safety. Browser default styles apply unless your markup includes its own CSS. Embedded styles in style tags still apply; external stylesheets may not load the same way depending on network and sandbox rules.
Can I format a full page versus a fragment?
Yes. If your paste starts with a DOCTYPE or an html element, the tool formats the whole document including the html wrapper. Otherwise it formats the fragment inside the synthetic body the parser creates, so you see only your snippet without forcing a full document shell.
Does this validate HTML?
It does not perform a separate validation pass with detailed errors like an XML validator. Parsing errors are absorbed by the HTML parser. For strict structure checks, pair this with an XML workflow or our XML formatter and validator when your content is XHTML-shaped.
How do I move from HTML to Markdown or back?
Use our HTML to Markdown converter when you need docs-friendly text, and the Markdown to HTML converter when you are authoring in Markdown but need publishable markup. This formatter is best when you already have HTML and want layout or size adjustments only.