Enter a domain and the validator finds the sitemap through robots.txt or the usual locations, or enter the sitemap URL directly. It checks the XML, the sitemap index and its child sitemaps, the URL count and lastmod dates, then fetches a sample of listed pages to catch redirects, errors and noindex tags.
Table of Contents
What is validated
The file must be well-formed XML with the sitemaps.org 0.9 namespace and a urlset or sitemapindex root. One sitemap may list up to 50,000 URLs and be up to 50 MB uncompressed; larger sites split into several files listed in an index. Gzipped sitemaps are read too.
lastmod must use the W3C date format, for example 2026-10-01 or a full ISO 8601 time. Every URL must be on the same host as the sitemap and should use https:// on an https site.
The sample URL check
Ten URLs spread across the sitemap are fetched without following redirects. A sitemap should list only final URLs that return 200: redirects, 404s and pages marked noindex waste crawl budget and send mixed signals to search engines.
WordPress sitemaps
Rank Math and Yoast publish /sitemap_index.xml, and WordPress core publishes /wp-sitemap.xml when no SEO plugin replaces it. If the sitemap shows a PHP warning or a blank line before the XML declaration, a plugin or theme is printing output too early.
XML Sitemap Validator at a glance
Official documentation: sitemaps.org protocol, Google: sitemaps overview.
Related guides: LiteSpeed Cache WordPress cPanel: Best Settings · DirectAdmin WordPress Manager and wp-cli: Easy Site Control.
Frequently asked questions
Do priority and changefreq still matter?
Google ignores both. It uses lastmod when the dates are consistently accurate, so keep lastmod tied to real content changes.
How do search engines find my sitemap?
Add a Sitemap line to robots.txt and submit the sitemap in Google Search Console and Bing Webmaster Tools. The robots.txt line is read by every major search engine.
Why are only the first 8 child sitemaps counted?
To keep the test fast, the validator reads up to eight child sitemaps and stops after about 40 seconds. Large sites can test a specific child sitemap by entering its URL.