HTML Structure Viewer

An HTML Structure Viewer is a developer tool that parses your HTML code and displays the tag hierarchy as an indented, expandable tree. It helps you quickly understand the nesting structure, identify parent-child relationships between elements, and spot potential markup issues — similar to the Elements panel in browser DevTools but with a clean, shareable text-based view.

Simply paste your HTML code into the left panel. The tool automatically parses it and displays the tag tree on the right. You can click the arrow icons to expand/collapse branches, use the search box to find specific tags, and copy the tree structure as indented text. Three sample HTML snippets are available via the "Sample" buttons to help you get started quickly.

Tags are color-coded by category for quick visual scanning:
Blue — Structural elements (html, body, div, section, nav, header, footer, main, aside, article)
Green — Text & inline elements (p, span, a, strong, em, code, pre, label)
Indigo — Headings (h1–h6)
Purple — List elements (ul, ol, li, dl, dt, dd)
Amber — Table elements (table, tr, td, th, thead, tbody)
Red — Form elements (form, input, select, textarea, button)
Pink — Media elements (img, video, audio, iframe, canvas, svg)
Gray — Meta & void elements (meta, link, br, hr, script, style)

Self-closing (void) tags do not have a closing counterpart and cannot contain children. The tool recognizes these standard void elements: area, base, br, col, embed, hr, img, input, link, meta, param, source, track, wbr. They appear in italic style in the tree view with a self-closing "/>" notation.

The parser is designed to be resilient. When it encounters mismatched closing tags, it attempts to auto-close unclosed elements by walking up the stack. If a closing tag doesn't match the current open element, the parser will close intermediate elements automatically and show a warning badge. While the tool works with incomplete HTML, we recommend using valid markup for the most accurate structural representation.

Absolutely. All parsing and rendering happens entirely in your browser using client-side JavaScript. Your HTML code is never sent to any server, stored, or transmitted over the network. You can safely use this tool with sensitive or proprietary markup without any privacy concerns. The page works fully offline once loaded.

The tool comfortably handles HTML documents up to approximately 50,000–100,000 characters with near-instant parsing. For very large files (200,000+ characters), you may notice a slight delay due to the recursive tree rendering. The real-time parsing uses a 300ms debounce to ensure smooth performance while typing. For optimal experience, we recommend keeping inputs under 50KB.

Yes! Click the "Copy" button above the tree panel to copy the entire structure as plain indented text to your clipboard. This format is perfect for documentation, code reviews, or sharing with colleagues. The indented text preserves all nesting levels, making it easy to read in any text editor or markdown file.

Type any keyword into the search box above the tree panel. Matching tag names or attribute values are highlighted in amber, and ancestor nodes automatically expand so you can see the full context. The match count appears beside the search box. Clear the search field to remove all highlights and restore the tree to its previous state.

While browser DevTools' Elements panel is excellent for live debugging, this tool offers unique advantages: (1) you can paste and analyze HTML snippets without opening a browser tab, (2) the indented text output is easy to copy into documentation or share, (3) color-coded tag categories give you an instant high-level overview, and (4) it works with raw HTML strings from any source — APIs, databases, or code editors — without needing to render the page.