HTML Formatter

HTML5 defines a rich vocabulary of semantic elements — header, nav, main, article, section, aside, footer — that convey document structure beyond visual presentation. Proper formatting makes these structural relationships visible through indentation. Void elements (img, br, hr, input, meta, link) have no closing tag and should appear on their own line or inline depending on context. Boolean attributes like disabled, checked, and required don't need values in HTML5 — their presence alone activates the behavior. Self-closing XHTML-style syntax (like <br />) is optional in HTML5 but remains common in JSX/React where it is required. Proper element nesting is critical — inline elements should not contain block elements (a p tag inside a span is invalid). Attribute quoting should be consistent — double quotes are the convention, though single quotes and unquoted values are technically valid for simple values. Indentation conventions vary by team and project — 2-space indentation is most common in front-end development, while 4-space is standard in some backend templating contexts. The AllTools HTML Formatter parses and re-indents HTML with configurable indent size, preserving content within pre and code elements that require exact whitespace preservation. Your HTML — which may contain inline scripts, API data, or user content — stays in your browser.

HTML formatting serves different purposes across various development contexts. Template engine output (Jinja2, EJS, Handlebars, Blade) often produces HTML with inconsistent indentation because template logic and HTML structure don't align neatly — formatting the rendered output helps debug template issues. CMS-exported HTML from WordPress, Drupal, or Contentful often carries legacy formatting, unnecessary wrapper elements, and inline styles that formatted output makes easier to clean up. Email HTML templates have unique formatting considerations — email clients ignore external stylesheets, requiring all CSS to be inline, and many modern HTML features aren't supported across Outlook, Gmail, Apple Mail, and mobile clients. Web scraping produces raw HTML that needs formatting to understand the page structure before writing extraction logic. REST API responses sometimes include HTML fragments that need formatting for inspection. Accessibility auditing benefits from formatted HTML that reveals heading hierarchy, ARIA attribute placement, and form structure. Compared to automated formatters like Prettier, the AllTools HTML Formatter provides on-demand formatting without project configuration — paste any HTML snippet and see it properly indented instantly, useful for one-off formatting tasks, code review preparation, and debugging.