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HTML Formatter — Beautify HTML Markup Online

HTML Formatter uses Prettier to apply consistent indentation and formatting to HTML markup. It handles nested elements, attributes, and inline content correctly.

HTML Document Structure and Indentation

Well-formatted HTML mirrors the document's visual hierarchy through indentation. Block elements (div, section, article, header, nav, main, footer, p, ul, ol, table) are placed on their own lines with child elements indented one level. Inline elements (span, a, strong, em, code) stay on the same line as surrounding text unless they are the sole content of a block.

Prettier's HTML formatter (used by SmartDevBox) respects the distinction between block and inline elements and handles edge cases like void elements (br, hr, img, input, meta, link) which do not have closing tags in HTML5. It also formats HTML attributes consistently — one attribute per line when there are many attributes on an element.

Formatting HTML Email Templates

HTML emails use table-based layouts for compatibility with email clients. The resulting markup is notoriously nested and verbose. Formatting the template makes it easier to find a specific row or cell, verify alt text on images, and check that all inline styles are correct. Since email templates are rarely served from a web server, all processing here is local — no corporate email content leaves your browser.

After formatting, use the HTML Preview tool to render the template side-by-side with the source, then use the HTML to Text tool to verify the plain-text fallback version looks correct for email clients that do not render HTML.

Common Use Cases

  • Formatting HTML templates copied from minified sources
  • Beautifying HTML email templates
  • Standardizing HTML formatting before code review

Frequently Asked Questions

How do I format HTML online?

Paste your HTML into SmartDevBox. The HTML Formatter detects HTML (looks for <!DOCTYPE, <html, <div, <p, or <span) and applies Prettier formatting automatically.

Privacy & Security

This tool runs entirely in your browser using client-side JavaScript. No data is sent to a server — your input never leaves your machine. SmartDevBox has no account system, no usage tracking, and no paid tier. See the Privacy & Security page for full details.

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