What is validated
- Well-formed XML, the <urlset> or <sitemapindex> root, and the sitemaps.org namespace.
- Every <loc>: present, absolute http(s), escaped, under 2,048 characters, not duplicated, on the sitemap's host.
- <lastmod> in W3C date format and not in the future; <changefreq> and <priority> values when present.
- Limits: 50,000 URLs and 50 MB uncompressed per file. Gzipped sitemaps (.xml.gz) are supported.
Statistics
URL count, duplicates, hosts, http vs https, top folders, folder depth, share of URLs with lastmod and the lastmod distribution by month. For a sitemap index, the first 20 child sitemaps are fetched and summarized.
Google ignores <changefreq> and <priority>; <lastmod> is used when it's consistently accurate.
Frequently asked questions
My sitemap is valid, why aren't the pages indexed?
A sitemap helps discovery, it doesn't force indexing. Pages still need to be crawlable, indexable (no noindex, a matching canonical) and worth indexing.
Should every URL be in the sitemap?
Only canonical, indexable URLs that answer 200. Redirects, noindex pages and parameter duplicates make the sitemap less trustworthy.