Sitemap Reality Check
Your sitemap makes claims about your site. This checks them. Structure and lastmod honesty first, then a live sample of the URLs it lists, tested for redirects, noindex, and errors.
Sitemaps are a trust exercise
Google treats your sitemap as a pile of hints, and it grades the source. A sitemap stuffed with redirecting URLs, 404s, and noindexed pages teaches crawlers to discount everything else in it, including the parts you care about. The usual offenders are automatic. The CMS lists URLs from before a redirect, the sitemap plugin stamps every entry with the same lastmod on every rebuild (which tells Google the dates are meaningless, so it ignores them), or noindexed utility pages leak into the file.
What it checks
- Structure: sitemap index vs urlset, entry count, cross-host entries, non-https entries, size sanity
- lastmod honesty: how many entries carry a
lastmod, and whether the values are suspiciously identical - A live sample of up to 10 URLs, spread across the file. Each one gets fetched and graded: clean 200, redirect (a sitemap should list final URLs), 4xx or 5xx,
noindex(which contradicts the entire point of listing it), or a canonical pointing at a different URL, meaning you listed the non-canonical twin.
It’s a sample, and I’d treat it as one. A clean 10 doesn’t vouch for the other ten thousand, but a dirty 3 out of 10 tells you where to start digging.
The tool finds your sitemap via robots.txt, or by checking common paths, parses it, and live-fetches a spread sample of up to 10 URLs. Large sitemaps are read up to 1 MB, and sampling means the result is an indicator, not a census. Nothing is stored.