Free tool
XML sitemap checker
Free sitemap checker: detect sitemap.xml, sitemap_index.xml, and Sitemap: lines from robots.txt.
XML sitemaps help search engines discover URLs. This checker looks for common sitemap paths and Sitemap: lines inside robots.txt, then reports whether the response looks like a sitemap.
Paths we try
/sitemap.xml, /sitemap_index.xml, www variants, plus any Sitemap: URLs advertised in robots.txt (capped for safety).
loc counts
We count <loc> tags as a rough size signal. Huge indexes may be truncated in the fetch preview — treat the count as approximate for very large files.