What is the difference between a sitemap and a sitemap index?

A sitemap is a urlset listing individual page URLs. A sitemap index is a sitemapindex listing other sitemap files. You need an index when a single sitemap would exceed 50,000 URLs or 50 MB uncompressed, splitting the URLs across multiple child sitemaps.

Are changefreq and priority still used by Google?

Google has stated it largely ignores changefreq and priority — it relies on its own crawl signals. They remain valid protocol elements and some other crawlers read them, but do not expect them to influence Googlebot. lastmod, when accurate, is the hint Google does pay attention to.

What format must lastmod use?

lastmod uses W3C Datetime / ISO 8601 — either a date like 2026-06-06 or a full timestamp like 2026-06-06T14:30:00+00:00. Keep it accurate; a lastmod that never matches real changes is treated as untrustworthy and may be ignored.

What are the size limits for a sitemap file?

A single sitemap may contain at most 50,000 URLs and must be no larger than 50 MB uncompressed. If either limit is reached, split into multiple sitemaps and reference them from a sitemap index, which itself may list up to 50,000 sitemaps.

What is the Sitemap Protocol Reference?

Reference for the XML Sitemap Protocol covering urlset, url, loc, lastmod, changefreq and priority elements, the sitemap index format and the image, video and news extensions. It runs free in your browser on Gera Tools, with nothing uploaded.

Sitemap Protocol Reference

Name: Sitemap Protocol Reference
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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The XML Sitemap Protocol

A sitemap is an XML file that lists a site’s URLs so crawlers can discover and prioritise them. The protocol defines a small set of elements — urlset, url, loc, lastmod, changefreq, priority — plus a sitemapindex format for large sites and extensions for images, video and news. This reference lists each element with its meaning, format and constraints.

Element reference

Element	Required	Value	Notes
`urlset`	Yes (root)	Namespace `http://www.sitemaps.org/schemas/sitemap/0.9`	Wraps all `url` entries
`url`	Yes	Container	One per page
`loc`	Yes	Absolute URL	Must match the sitemap host; escape `&` as `&`
`lastmod`	No	W3C datetime (e.g. `2026-06-06`)	The hint Google actually reads; keep it accurate
`changefreq`	No	`always` / `hourly` / `daily` / `weekly` / `monthly` / `yearly` / `never`	Largely ignored by Googlebot
`priority`	No	`0.0`–`1.0`, default `0.5`	Relative within your site; does not affect cross-site ranking

For a sitemap index, replace urlset with sitemapindex and url/loc with sitemap/loc.

Minimal valid sitemap

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://example.com/</loc>
    <lastmod>2026-06-06</lastmod>
    <changefreq>weekly</changefreq>
    <priority>1.0</priority>
  </url>
</urlset>

When you exceed 50,000 URLs or 50 MB, split the file and list the parts in an index:

<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <sitemap>
    <loc>https://example.com/sitemap-1.xml</loc>
    <lastmod>2026-06-06</lastmod>
  </sitemap>
</sitemapindex>

Reference the file from robots.txt with a Sitemap: directive and submit it in Google Search Console and Bing Webmaster Tools.

Extensions: image, video and news

The core protocol covers HTML pages. Three official namespace extensions add richer metadata:

Image extension (xmlns:image="http://www.google.com/schemas/sitemap-image/1.1"): Add image:image / image:loc children under each url to tell Google about embedded images. Useful for photography sites, e-commerce product images, and image galleries.

Video extension (xmlns:video="http://www.google.com/schemas/sitemap-video/1.1"): Declare video title, description, thumbnail, and duration inside a video:video block. Required for Google to show video results with rich preview data.

Google News extension (xmlns:news="http://www.google.com/schemas/sitemap-news/0.9"): Add news:news blocks with publication name, language, and publication date. Google News only indexes articles published within the past two days, so this sitemap must be regenerated continuously on news sites.

Key rules and common mistakes

loc is the only required child of url. Omitting lastmod is fine; a missing or stale lastmod is worse than no lastmod.
All loc URLs must share the host and scheme of the sitemap’s own URL — a sitemap at https://example.com/sitemap.xml cannot list http://other.com/page.
Limits: 50,000 URLs and 50 MB uncompressed per file. Gzip-compress large sitemaps (.xml.gz) to stay under the transfer threshold.
changefreq and priority are largely ignored by Googlebot; investing time in accurate lastmod values is far more worthwhile.
Sitemaps only help with discovery, not ranking. A URL in a sitemap still needs inbound links and good content to rank.