sitemap.xml file format: the Sitemaps XML protocol

Introduction

A sitemap lists the pages of a site so that search engines can find them. The usual file is sitemap.xml at the top of the site, and the format is the Sitemaps XML protocol of sitemaps.org. A large site cannot list everything in one file, so a second kind of file, the sitemap index, lists the sitemaps instead of pages. A sitemap can be gzip-compressed, as sitemap.xml.gz.

Structure

The file is XML in UTF-8. The root is a urlset in the namespace http://www.sitemaps.org/schemas/sitemap/0.9, with a url for each page. Only loc, the address, is required; lastmod, changefreq and priority are optional. The elements page has each one.

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://example.com/</loc>
    <lastmod>2024-02-29</lastmod>
    <changefreq>weekly</changefreq>
    <priority>1.0</priority>
  </url>
  <url>
    <loc>https://example.com/about</loc>
  </url>
</urlset>

The index has the root sitemapindex, and a sitemap with a loc and an optional lastmod for each file it lists. A sitemap may carry extensions for images, video, news and the language versions of a page, each in its own namespace. The limits are 50,000 addresses and 50 MB for one file, before compression.

In the explorer

Drop sitemap.xml, sitemap_index.xml or a similarly named file on the explorer. If its root is urlset or sitemapindex in the sitemaps.org namespace it opens as a sitemap: the XML tree, a table of every URL with its dates, frequency, priority and extensions, a summary (the number of addresses, the hosts, the extensions in use and the range of last-modified dates) and a list of every rule that is broken, each with its line and column. An index shows the sitemaps it lists, by address; the explorer does not fetch them. A sitemap.xml.gz opens through the gzip viewer, and the file inside it as a sitemap.

The options bar has a Sitemap address box. Give the address the sitemap is served at and every URL is checked against the protocol’s rule that it must use the sitemap’s protocol, host and port and lie in its directory. Any other file with such a name (an RSS feed, a page of text, an XML file in another namespace) opens as XML as it always did. The XML highlighting is used for the text.

Not described

Known, not yet covered

Viewer: the text sitemap (one address per line) and RSS and Atom feeds used as sitemaps are not read as sitemaps; they open as text and XML.
Viewer: the schema files sitemap.xsd and siteindex.xsd were not read, so the order of the elements inside a url is not checked, and the extension elements are checked against Google’s documentation, not their schemas.
Viewer: the Google mobile extension is recognised by its namespace only; no page about it was read.
Viewer: the older Google namespace http://www.google.com/schemas/sitemap/0.84 is not accepted as a sitemap, since no page read for these notes names it.
Viewer: whether an address returns a page, and whether alternate-language links point back at each other, cannot be checked from one file.

Unknown

Reference: whether a sitemap index may list another index is not stated on the sitemaps.org page we read; the viewer only notes an address that looks like an index.

sitemap.xml File Format