What is an XML sitemap?

XML sitemap: definition and meaning

An XML sitemap is a file in XML format, usually located at /sitemap.xml, that lists the URLs of a website that should appear in search engines. It follows the sitemaps.org standard and is read by Google, Bing, and other search engines. Optionally, each URL can include the date of its last change as well as details about images, videos, or language versions.

Important: a sitemap is a hint, not a command. It helps search engines discover new or hard-to-reach pages, for example on large online stores, young websites, or pages with few internal links. Whether a URL is actually indexed is decided by the search engine based on quality and relevance.

How the sitemap works

The file contains one entry per page with the full URL and, ideally, the date of the last substantive change (lastmod). A single sitemap may contain at most 50,000 URLs or 50 MB (uncompressed). Larger websites split it up and combine the parts in a sitemap index file.

The sitemap is made known through Google Search Console, Bing Webmaster Tools, or a Sitemap line in the robots.txt file. Google does not evaluate the priority and changefreq fields, and it uses lastmod only if the dates are reliably accurate. Only the URL itself is mandatory; everything else is optional.

Real-world example: a sitemap for an online store

A specialist garden supplies retailer runs a store with around 12,000 product pages, and new items take weeks to show up on Google. The store system now automatically generates one sitemap each for products, categories, and guide articles, plus an index file. The lastmod date changes only when content really changes.

Filter pages, shopping cart, search results, and redirects are deliberately left out, so the sitemap contains only pages with search potential. In Search Console, the retailer can see for each sitemap how many URLs were found and indexed, and spots problems such as excluded or faulty pages early.

What belongs in the sitemap—and common mistakes

A good sitemap contains only pages you actually want to see in search: reachable, indexable, and canonical to themselves. That also makes it a diagnostic tool. If error pages or redirects show up in it, something is wrong with the website, and search engines lose trust in the file.

• Include: indexable pages with status code 200
• Leave out: redirects, 404 pages, noindex pages
• Leave out: filter, sorting, and search result URLs
• Update lastmod only for substantive changes
• List the sitemap URL in the robots.txt file

Imple­menta­tion: how to set up the sitemap

WordPress (since version 5.5), Shopify, and Shopware generate sitemaps automatically. For custom-built websites, the sitemap should be generated from the database so it never goes stale. Nano Concepts sets up sitemaps as part of technical SEO audits and relaunches and checks them in Search Console after launch.