A structural HTML diff tool that understands DOM trees — not just text. Detect element changes, attribute modifications, text content differences, and structural shifts.
A client-side HTML comparison tool that parses DOM structure semantically — not just text. Fast, private, and free for web developers.
Color-coded highlights for every difference: green for additions, red for removals, yellow for modifications. Full element-path reporting for nested HTML structures.
Efficient recursive algorithms compare HTML documents with hundreds of elements in under a second. No server round-trip, no loading spinners.
All HTML parsing and diffing happens in your browser using JavaScript. Your data never leaves your device — zero server uploads, zero logging.
Start comparing HTML documents in three simple steps — no installation or signup needed.
Enter or paste two HTML documents into the left (Base) and right (Contrast) editor panels. You can also drag-and-drop files or import from a URL.
Click the 'Compare' button. The tool instantly parses both inputs, normalizes structure, and produces a semantic diff.
View color-coded diff results with additions, removals, and modifications highlighted inline. Navigate differences by category in the sidebar.
Unlike text-based diff tools, our HTML comparator understands DOM structure. It parses, normalizes, and recursively compares — so formatting changes and whitespace differences never produce false diffs.
Both HTML inputs are parsed into Virtual DOM trees using parse5. Elements, attributes, text nodes, comments, and doctypes are all represented as structured nodes — so whitespace differences never create false positives.
The algorithm traverses both DOM trees recursively, comparing nodes at each level. It detects added/removed elements, attribute changes, text modifications, and structural differences at every nesting level.
Element attributes are compared independently — detecting added, removed, or changed attributes. Text content within elements is compared after whitespace normalization.
Each difference is mapped to its source position and rendered with color-coded highlights — green for additions, red for removals, yellow for modifications — with full element path context.
HTML comparison is essential across web development workflows.
Compare rendered HTML output from template engines like Handlebars, EJS, or Jinja2 to verify correct rendering across different data inputs and edge cases.
Verify component output changes during refactoring, ensuring HTML structure remains correct after code modifications and UI updates.
Compare HTML email templates across versions, ensuring layout changes are intentional and no content is accidentally modified or broken.
Detect structural changes in web pages by comparing HTML snapshots, useful for monitoring page updates, content changes, or scraping target modifications.
Load HTML data into the comparison result page by passing URL query parameters. Useful for sharing diff results, CI/CD integration, or linking from documentation.
Pass publicly accessible URLs to the base and contrast parameters. The tool will fetch and compare the HTML content from these URLs automatically.
Encode your HTML content as a Base64 string and pass it directly in the URL. Use base-64.com to encode/decode your data.