Compare two sitemap snapshots to see added, removed, and modified URLs — great for post-migration audits.
Quick answer
Paste two sitemap URLs (before and after) into /tools/sitemap-diff. You'll see added, removed, and lastmod-changed URLs side-by-side. Perfect for validating a site migration or CMS switch.
What it does
Parses XML and sitemap indexes recursively
Highlights added, removed, and modified URLs
Flags URLs whose lastmod shifted
Exports the diff as CSV
Warns when a sitemap shrinks by >20% (a common migration red flag)
Where to find it in Lemwatch
/tools/sitemap-diff — public, no signup. Paired with the in-app Sitemap Monitoring for continuous tracking.
How to use it
Enter the "before" sitemap URL (e.g. archive.org copy or old CDN).
Enter the "after" sitemap URL.
Click Compare.
Review added/removed URLs and download the CSV.
Enable continuous monitoring inside Lemwatch to be alerted on future diffs.
FAQ
Can I compare two files instead of two URLs?
Not in the free tool. Upload both to public URLs first, or use in-app sitemap monitoring.
What if the sitemap is huge?
The tool handles up to 500,000 URLs. Beyond that, split the sitemap index or use the paid API.