Google imposes two limits: 50,000 URLs per sitemap file and 50MB uncompressed. Large sites quickly hit these limits and need a Sitemap Index.
Sitemap Index Structure
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<sitemap>
<loc>https://example.com/sitemap-posts.xml</loc>
<lastmod>2025-05-01</lastmod>
</sitemap>
<sitemap>
<loc>https://example.com/sitemap-products.xml</loc>
<lastmod>2025-05-01</lastmod>
</sitemap>
</sitemapindex>
Splitting Strategy
Split by content type (posts, products, categories) rather than alphabetically. This lets you prioritize crawl budget for your most important content types.
