Sitemap index
<sitemapindex>
The root element of a sitemap index: a list of sitemaps rather than a list of URLs, in the same namespace as an ordinary sitemap.
A sitemap index shares its namespace with a sitemap and differs only in its root element and children. That is what makes the two easy to confuse and easy to detect: whichever root element is present decides which set of rules applies.
An index may point at up to 50,000 sitemaps, and it may not point at another index. One level of nesting is all the protocol allows.
- Format
- Sitemap index
- Namespace
- Sitemap protocol 0.9
- Parent
- None — this is the document element
- How many
- Exactly one, as the document element.
What our validator does
Detected by its root element and checked separately from a sitemap: child count, missing <loc> and lastmod coverage.
Broken and fixed
Both documents below are well-formed XML — that is the point of this corpus — and both are run through the validator on every test run. The verdicts here are what it returned, not what we expect it to.
<?xml version="1.0" encoding="UTF-8"?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
</sitemapindex>Sitemap index contains no child sitemaps.<?xml version="1.0" encoding="UTF-8"?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<sitemap>
<loc>https://example.com/sitemap-1.xml</loc>
<lastmod>2026-08-10</lastmod>
</sitemap>
</sitemapindex>Where it reaches
- FormatsSitemap indexThe format page, and how it differs from a plain sitemap.
- ToolsSitemap validatorDetects which of the two you pasted and applies the right checks.
Related elements
- <sitemap>One child sitemap in an index: a required <loc> pointing at the sitemap file, and an optional <lastmod> for it.
- <urlset>The root element of every sitemap. Its namespace declaration is what makes the document a sitemap rather than a list of URLs.
- <loc>The URL of a child sitemap. Same element name as in a sitemap, different meaning: it points at a file, not at a page.
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