Validate any site's sitemap.xml structure against Google's documented rules. Catches malformed XML, future-dated lastmod tags, missing or invalid loc URLs, exceeded URL counts (Google's 50,000 cap), and oversized files (Google's 50 MB cap).
Free. No signup. Rate-limited to 30 checks per IP per hour. SSRF-guarded — internal IPs and bare hostnames are rejected.
Paste a domain (we'll try the conventional sitemap paths) or a full sitemap URL. SSRF-guarded, rate-limited 30 / hour.
Sitemap returns the application shell instead of XML.The most common Vercel / Next.js / SPA misconfiguration: the catch-all route serves index.html for every unmatched path, including /sitemap.xml. Google sees an HTML document at a URL that should be XML, ignores it, and your URL submission stops working. The checker flags this as "wrong root element" and tells you the actual content-type.
Future-dated lastmod values.Almost always a server-time bug — the application is generating ISO timestamps with a wrong clock or timezone, or the sitemap generator caches the build time and never re-derives. Google may stop trusting lastmod across the entire sitemap. The checker flags any lastmod > 24 hours in the future (the 24-hour window is for server-clock skew).
Sitemap-index pointing at dead child sitemaps.A common refactor symptom: the index file references /sitemap-pages.xml, /sitemap-posts.xml, /sitemap-products.xml, but one of those returns 404 because a route was renamed. Google fetches the index, follows the broken child, and silently skips that URL bucket. The full Seoxpert audit BFS's through sitemap indexes and probes every child; this single-file checker validates one sitemap at a time.
A sitemap checker fetches your sitemap.xml (or sitemap_index.xml), parses the XML, and validates it against Google's documented rules. The checker reports malformed XML, wrong root element, missing or invalid <loc> URLs, future-dated <lastmod> values (a strong signal that something is broken), and exceeded size / URL count limits (50,000 URLs and 50 MB uncompressed are Google's hard caps).
Paste your domain (e.g. example.com) or a full sitemap URL. If you give just the domain, the checker tries the conventional paths in order: /sitemap.xml, /sitemap_index.xml, /sitemap-index.xml, /sitemaps.xml. The first one that returns 200 is validated. If your sitemap lives at a non-standard path, paste the full URL.
A common Vercel / Next.js / SPA misconfiguration: the catch-all route serves the application shell HTML for every unmatched path, including /sitemap.xml. The checker flags this as "wrong root element" — the response parses but the root is <html>, not <urlset> or <sitemapindex>. Fix: ensure your /sitemap.xml route returns XML with the correct content-type, or generate it as a static file.
Google's documented limits are 50,000 URLs per sitemap file and 50 MB uncompressed body size. If your site has more than 50K URLs, split into multiple sitemap files and reference them from a sitemap index file (sitemap_index.xml). The checker flags both limits — going over either causes Google to ignore the entire file.
lastmod tells Google when a URL was last changed. A date in the future is almost always a server-time bug — the application is generating ISO timestamps with a wrong clock or timezone. Google may ignore the entire entry. The checker flags any lastmod that is more than 24 hours ahead of the current UTC time (the 24-hour grace window is for server-clock skew across regions).
It should be referenced from robots.txt with a Sitemap: <full URL> line, but the URLs inside the sitemap should not include pages that robots.txt disallows — that sends conflicting signals to Google. The Seoxpert full audit checks this consistency automatically; this checker validates the sitemap file in isolation.
Whenever the underlying URL set or content changes. For most sites, a daily regeneration is enough. Static-site generators usually rebuild the sitemap on every deploy — that's ideal. lastmod values should reflect actual content changes, not just regeneration timestamps; Google trusts lastmod less when every URL gets the same lastmod on every deploy.
A Seoxpert scan validates the sitemap plus 230+ other signals — SEO, security, performance, AI / GEO citability, content gaps. Free first scan.