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Performance & SEO

What is an XML sitemap?

An XML sitemap lists the URLs of a site, with optional lastmod dates, so crawlers can find them. It is also a ready-made list of pages to warm.

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An XML sitemap is a file that lists the URLs of a site for search engines, following the sitemaps.org protocol. Each entry has a loc, the absolute URL, and optional fields such as lastmod, the date the page last changed. A sitemap file holds up to 50,000 URLs, and a sitemap index groups several files.

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://example.com/pricing</loc>
    <lastmod>2026-10-18</lastmod>
  </url>
</urlset>

Listing a URL does not guarantee that it is crawled or indexed. An accurate lastmod helps crawlers find changed pages, and it should match the page's real changes, like the `Last-Modified` header.

  • A sitemap is also the natural input for cache warming: it already lists the pages you want served fast.
  • Pages that change on every deploy are the ones a purge leaves cold.
  • Keep it to canonical, indexable URLs. Redirects and blocked pages waste crawl budget.

Related terms

References

  1. sitemaps.org: Sitemaps XML formathttps://www.sitemaps.org/protocol.html
  2. Google: Crawl budget management for large siteshttps://developers.google.com/crawling/docs/crawl-budget

Warm your cache after every deploy

sitewarm requests the pages in your sitemap after a deploy and reports the cache state the CDN returns for each one, with the vantage point it was measured from.

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