Sitemap Index Files Explained

If you run a massive e-commerce store, a large publisher network, or a programmatic SEO site, you will quickly hit the hard limits of standard XML sitemaps: 50,000 URLs or 50MB uncompressed file size.

When this happens, you must split your URLs across multiple sitemap files. To submit these multiple files to Google efficiently, you use a Sitemap Index File.

What is a Sitemap Index?

A sitemap index is simply a sitemap of sitemaps. Instead of listing individual webpage URLs, it lists the URLs of your other XML sitemap files.

Sitemap Index Syntax

The XML schema for a sitemap index uses <sitemapindex> and <sitemap> instead of <urlset> and <url>.

<?xml version="1.0" encoding="UTF-8"?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <sitemap>
    <loc>https://example.com/sitemap-products.xml</loc>
    <lastmod>2026-08-01</lastmod>
  </sitemap>
  <sitemap>
    <loc>https://example.com/sitemap-blog.xml</loc>
    <lastmod>2026-08-02</lastmod>
  </sitemap>
</sitemapindex>

Best Practices for Sitemap Indexes

• Categorize Logically: Don't just split URLs arbitrarily (e.g., sitemap1, sitemap2). Group them logically by site section (e.g., products, categories, blog, authors). This allows you to track indexation rates per category in Google Search Console.
• Submit the Index: You only need to submit the Sitemap Index file to Google Search Console. Google will automatically discover and process all the sub-sitemaps listed within it.
• Keep it Clean: Just like regular sitemaps, if a sub-sitemap is deleted or redirects, remove it from the sitemap index.