Paste your original HTML in the left panel and the updated version in the right panel, then click Find Differences. Added lines appear in green, removed in red. Upload .html, .htm, .xhtml, or .svg files directly. All processing runs in your browser - no code is sent to a server.
How to use this tool
Paste or upload your original HTML on the left and the changed version on the right. Click "Find Differences." The diff shows every added and removed line with line numbers. Toggle Unified or Side-by-Side view. The file upload dialog filters to .html, .htm, .xhtml, and .svg files.
HTML diff considerations
Attribute order
HTML attributes on a tag are compared as plain text per line. If a formatter reorders attributes (e.g., class before id vs after), the entire tag line appears changed even if the rendered output is identical.
Self-closing tags
A change from <br> to <br /> (or vice versa) will show as a changed line. Both are valid HTML5, but the tool treats them as different strings.
Whitespace and indentation
HTML is whitespace-insensitive in the browser, but the diff compares source text exactly. Reformatted HTML with different indentation will show many changed lines even if the document structure is unchanged. Format both files consistently before diffing for the cleanest output.
Use cases
Email template versioning
Email HTML is often edited directly. Comparing two versions of an email template shows exactly which elements, copy, or links changed - important for audit trails and for catching broken tags before sending.
CMS template updates
When a CMS exports HTML for a page, comparing the exported HTML before and after an edit shows which parts of the template or content were modified.
Scraped page change detection
Compare two scraped versions of a webpage to detect changes in structure, content, or links since the last crawl.
FAQs
Can I compare SVG files?
Yes. SVG files are XML/HTML-like text. The file upload accepts .svg files and the diff compares the raw markup line by line.
Does this render the HTML?
No. The tool compares the raw source text. It does not open a browser context or compare visual rendering.
Is my HTML private?
Yes. All processing runs in your browser. No code is sent to any server.