Glossary

XML Sitemap

Definition
An XML sitemap is a file (typically named sitemap.xml) that lists the URLs on a website along with optional metadata like last modification date, change frequency, and priority. It helps search engines discover and crawl pages more efficiently.

XML sitemaps are one of the most direct ways to communicate with search engines about your site’s content. While search engines can discover pages through links alone, sitemaps ensure that new, updated, or deeply nested pages are found quickly.

What an XML sitemap contains

Each entry in an XML sitemap includes a <loc> (the URL), and optionally <lastmod> (when the page was last changed), <changefreq> (how often it changes), and <priority> (relative importance). Search engines use these hints to allocate crawl budget, though they may not follow the suggestions exactly.

XML sitemap best practices

Only include canonical, indexable URLs. Exclude pages with noindex tags, 3xx redirects, or 4xx/5xx errors. Keep sitemaps under 50,000 URLs (use sitemap index files for larger sites). Update <lastmod> only when content actually changes — search engines penalize sites that set fake lastmod dates.

Sitemaps and IATO

IATO can cross-reference your XML sitemap against crawl data to identify coverage gaps: pages in the sitemap that return errors, important pages missing from the sitemap, and indexable pages excluded from it. This is part of the technical SEO audit workflow covered in our audit guide.

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