Sitemap Reality Check
Your sitemap makes claims. This checks them — structure and lastmod honesty first, then a live sample of listed URLs tested for redirects, noindex, and errors.
Sitemaps are a trust exercise
Google treats your sitemap as a set of hints, and it grades the hinter. A sitemap full of redirecting URLs, 404s, or noindexed pages teaches crawlers to discount everything else it says — including the parts you care about. The most common offenders are automatic: the CMS lists URLs pre-redirect, the sitemap plugin stamps every URL with the same lastmod on every rebuild (a tell that the dates are meaningless, so Google ignores them), or noindexed utility pages leak into the list.
What it checks
- Structure: sitemap index vs. urlset, entry count, cross-host entries, non-https entries, size sanity
- lastmod honesty: how many entries have
lastmod, and whether the values are suspiciously identical - A live sample (up to 10 URLs, spread across the file): each is fetched and graded — clean 200, redirects (a sitemap should list final URLs), 4xx/5xx,
noindex(listing a noindexed page is a direct contradiction), or canonicals pointing at a different URL (you listed the non-canonical twin)
The sample is exactly that — a sample. A clean 10 doesn’t certify the other ten thousand, but a dirty 3-of-10 tells you where to dig.
The tool finds your sitemap via robots.txt (or common paths), parses it, and live-fetches a spread sample of up to 10 listed URLs. Large sitemaps are read up to 1 MB; sampling means results are an indicator, not a census. Nothing is stored.