Compare HTML
Compare two HTML files online. Diff the DOM structure node by node or preview both documents side by side in a sandbox. Free, and nothing is uploaded.
Files never leave your browser.
About HTML Diff
Compares two HTML documents structurally (DOM-style) or rendered side-by-side. Useful for tracking template changes, CMS exports, or generated markup.
How to use
- Paste or load both HTML snippets.
- Pick a mode under Options: Structural (DOM tree diff) or Rendered (visual).
- Inspect changes attribute by attribute and node by node.
Try a sample
A hero section with a new CTA button and headline change.
What this tool doesn't handle
- External resources (CSS, scripts, fonts) are not fetched; Rendered mode shows only inline styling.
- Auto-closing tag inference may differ from a browser parser for malformed input.
Frequently asked questions
Do my files ever leave my browser?
No. Every comparison runs locally in your browser. Nothing you paste, drop, or load is uploaded to a server; the tool keeps working even if you go offline after the page loads.
Is this tool free to use?
Yes. All DiffResolver tools are free, with no account, sign-up, or installation. Because processing happens on your device, there are no server-imposed usage limits.
What is the difference between structural and rendered mode?
Structural mode diffs the parsed DOM tree (tags, attributes, and text nodes), which suits templates and generated markup. Rendered mode shows both documents side by side for visual review.
Does the tool load external CSS or scripts?
No. External resources are never fetched, both for privacy and for deterministic results. Rendered mode reflects inline styling only.
Is there a file size limit?
No server limit applies, because nothing is uploaded. The memory of your device sets the practical limit. Above 10 MB for text, 40 MB for images, 100 MB for documents, or 500 MB for archives, the tool warns you that the work can be slow, but it never blocks the file.
Does this tool work offline?
Yes. The browser keeps a copy of the tool after the first visit, so a page you opened before still works without a network. You can also install DiffResolver as an app from the browser menu. Installation stays optional; the site works the same in a normal tab.
Where is my data stored?
Your files are stored nowhere. They stay in the memory of the page and are gone when you close the tab. Only what you save yourself stays in this browser: a snapshot, your tool options, and your theme. To remove it, open Settings and select Clear all local data.