An XML file that references multiple sitemap files, used when a site has too many URLs for a single sitemap.
A sitemap index file is an XML file that acts as a directory for multiple sitemap files. Since a single sitemap can contain a maximum of 50,000 URLs and must be under 50MB, large websites split their URLs across multiple sitemaps and reference them all from a sitemap index.
The sitemap index uses a `<sitemapindex>` root element containing `<sitemap>` entries, each with a `<loc>` pointing to an individual sitemap file and an optional `<lastmod>` date.
Search engines follow the sitemap index to discover and process all child sitemaps. Many CMS platforms (WordPress, Shopify) automatically generate sitemap indexes when the URL count exceeds the limit.
<?xml version="1.0" encoding="UTF-8"?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<sitemap>
<loc>https://example.com/sitemap-posts.xml</loc>
<lastmod>2025-03-01</lastmod>
</sitemap>
<sitemap>
<loc>https://example.com/sitemap-products.xml</loc>
<lastmod>2025-02-28</lastmod>
</sitemap>
</sitemapindex>SitemapKit's API lets you discover, extract, and parse XML sitemaps from any domain. Get structured JSON data with all sitemap elements including Sitemap Index.