Sitemap Validator

SEO sitemap validation tool. Checks errors, warnings, and passed items in detail.

Sitemap Validator is a Chrome extension for SEO professionals and web developers who want to verify their sitemaps without leaving the browser. ── WHAT IT VALIDATES ── ✅ XML, TXT, and gzip-compressed sitemaps ✅ File size (50 MB limit) and URL count (50,000 limit) ✅ XML syntax and required namespace ✅ URL scheme (http/https) and maximum length (2,048 chars) ✅ <lastmod> format (W3C Datetime) and future-date detection ✅ UTF-8 encoding integrity ✅ Domain authority — flags cross-domain or unauthorized subdomain URLs ✅ Deprecated tags: <priority> and <changefreq> (ignored by Google) ✅ Duplicate lastmod concentration warnings ✅ Multiple host mixing warnings ── HREFLANG ANALYSIS ── For sitemaps using <xhtml:link rel="alternate">, the extension automatically checks: • Self-referencing links • Duplicate language codes • Missing reciprocal links • BCP 47 language code format • Unofficial region codes (EU, UN, UK) • Missing x-default ── LIVE URL SAMPLING ── Automatically fetches up to 20 URLs from your sitemap and checks: • HTTP status codes • Redirect detection • Canonical tag match • Last-Modified header vs. <lastmod> value drift ── SITEMAP DISCOVERY ── Reads the current page's robots.txt to detect sitemap URLs automatically, with bulk validation support for sitemap index files. ── HEALTH SCORE ── All checks are aggregated into a color-coded health score (0–100%) so you can prioritize fixes at a glance. ── LANGUAGES ── Available in English and Japanese. ── PRIVACY ── No data is collected or sent to any third-party server. Sitemap content and validation results are stored only in your local browser session storage and cleared when the session ends.