Sitemap Index

A Sitemap Index is a special XML file that contains links to multiple individual sitemaps (sitemap.xml). It is used to structure large websites and helps search engine robots find and index all of a project’s pages more quickly.

What is a Sitemap Index?

If a website contains many pages, images, categories, or subdomains, a single standard sitemap (sitemap.xml) can become too large. In this case, a sitemap index is created, which consolidates all sitemaps into a single file.

A Sitemap Index is a “list of sitemaps” that directs search robots to the necessary XML files.

Example of a Sitemap Index

Example of a standard sitemap_index.xml file:

xml

<?xml version=”1.0″ encoding=”UTF-8″?>

<sitemapindex xmlns=”https://www.sitemaps.org/schemas/sitemap/0.9″>

<sitemap>

<loc>https://example.com/sitemap-pages.xml</loc>

<lastmod>2025-11-01</lastmod>

</sitemap>

<sitemap>

<loc>https://example.com/sitemap-products.xml</loc>

<lastmod>2025-11-02</lastmod>

</sitemap>

<sitemap>

<loc>https://example.com/sitemap-blog.xml</loc>

<lastmod>2025-11-05</lastmod>

</sitemap>

</sitemapindex>

Each <sitemap> block specifies:

• <loc> — the link to the sitemap.
• <lastmod> — the date of the last update.

Search robots (Googlebot, YandexBot) regularly check the sitemap_index.xml to determine which sections need re-indexing.

When is a Sitemap Index Needed?

A Sitemap Index is used if:

• The site contains more than 50,000 URLs (the limit for a single sitemap).
• The size of a single sitemap exceeds 50 MB (uncompressed).
• The project has multiple language or regional versions.
• Many content types are used — pages, images, videos, news, products.
• There are subdomains with their own sitemaps.

For small sites, a single sitemap.xml is sufficient. But for large portals, e-commerce stores, or media outlets — a sitemap index is essential.

Advantages of a Sitemap Index

• Simplifies navigation for search robots. The robot immediately understands the site’s structure and finds updated sitemaps faster.
• Eases administration. You can separate sitemaps by content type (pages, products, news) and update them independently.
• Improves indexing efficiency. Google and Yandex find new pages and changes more quickly.
• Supports scalability. Easy to add new sitemaps without recreating the main structure.

How to Create a Sitemap Index

1. Generate individual sitemaps (e.g., sitemap-pages.xml, sitemap-products.xml, sitemap-blog.xml). Each should contain no more than 50,000 URLs and be under 50 MB.
2. Create a sitemap_index.xml file and include links to all individual sitemaps.
3. Place it in the website root, usually at https://example.com/sitemap_index.xml.
4. Specify the path in robots.txt:
5. robots.txt
6. Sitemap: https://example.com/sitemap_index.xml
7. Submit it via webmaster tools:
   • Google Search Console → Index → Sitemaps.
   • Yandex.Webmaster → Indexing → Sitemaps.

Types of Sitemaps to Include

A Sitemap Index can consolidate different types of XML files:

Google’s Technical Requirements

• Maximum of 50,000 links in a single sitemap.
• Maximum of 50,000 sitemaps in one index file.
• Size of a single sitemap (uncompressed) — up to 50 MB.
• All links must be absolute (https://example.com/page).
• The file must be in UTF-8 encoding.
• Gzip compression (.xml.gz) is allowed.

Checking a Sitemap Index

Use:

• Google Search Console — shows the processing status of each sitemap.
• Yandex.Webmaster — displays the last crawl date.
• Screaming Frog SEO Spider or Ahrefs Webmaster Tools — checks structure and errors.

Errors to Look For:

• Incorrect XML format.
• Broken links.
• Duplicate or blocked pages (Disallow).
• Outdated <lastmod> dates.
• Sitemap doesn’t match the actual site structure.

Best Practices

• Separate sitemaps by content type (pages, images, blog).
• Specify accurate update dates (<lastmod>).
• Use .gz compression if there are many files.
• Store the sitemap and index in the domain root.
• Add new sitemaps to the index file without altering old ones.
• Do not include blocked or non-canonical URLs in the sitemap.

Example Structure for a Large Site

text

https://example.com/sitemap_index.xml

├── sitemap-pages.xml

├── sitemap-blog.xml

├── sitemap-products.xml

├── sitemap-images.xml

└── sitemap-news.xml

Conclusion

A Sitemap Index is a tool that helps search engines quickly and efficiently find all parts of a large website. It simplifies sitemap management, speeds up indexing, and increases the chances of new pages appearing in search results.