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XML sitemap: what does it do for search engines?
A list of addresses you hand to search engines that says: these are the pages that matter, and this is when they last changed.
An XML sitemap is a file that gives search engines a list of a site's pages, videos and other files, along with details such as when each page was last modified. It helps crawlers find the pages you consider important, but it does not guarantee they will be crawled or indexed.
In short
- The format comes from the sitemaps.org protocol, UTF-8 encoded XML.
- One file holds up to 50,000 URLs and 50 MB uncompressed.
- Google says sites of about 500 pages or fewer may not need one.
- You can point to it from robots.txt with a Sitemap: line.
What goes into an XML sitemap?
Google describes a sitemap as a file where you provide information about the pages, videos and other files on your site. It also signals which pages you consider important and when they were last updated [1].
The format is set out in the sitemaps.org protocol. Files must be UTF-8 encoded, and special characters in data values have to be entity-escaped [2].
| Tag | Required? | Purpose |
|---|---|---|
| urlset | Yes | Wraps the whole file |
| url | Yes | Wraps each entry |
| loc | Yes | Full address of the page |
| lastmod | No | When the page was last modified |
| changefreq | No | How often the page is likely to change; treated as a hint |
| priority | No | Importance relative to other pages on the same site; default 0.5 |
Source: sitemaps.org protocol [2].
How does Google use a sitemap?
Google finds pages in three ways: it has visited them before, it follows a link from a known page, or it reads them from a sitemap you submit [3]. A sitemap adds to links; it does not replace them.
Listing a URL in a sitemap is also a weak hint that it is the preferred version. When duplicates exist, a canonical tag or a redirect carries much more weight [4].
Most importantly, Google states that a sitemap does not guarantee every item in it will be crawled and indexed [1].
How big can a sitemap get?
Does a small site really need a sitemap?
Google says small sites, about 500 pages or fewer, may not need one. It points to larger sites, new sites with few external links and sites heavy on video or images as the ones that benefit most [1].
A contractor who just launched a site that nobody links to yet fits the new site case, so a sitemap is a cheap way to announce every page on day one. Solid internal linking does the rest.
Where does the sitemap live and how is it announced?
The protocol lets you declare the sitemap's location in your robots.txt file with a line starting with Sitemap: followed by the full URL. The line works wherever it sits relative to user-agent lines, and you can list more than one sitemap [2].
What sitemap mistakes are common?
- Listing pages that return a 404 error or redirect elsewhere.
- Including pages blocked in robots.txt or tagged noindex, which sends mixed signals.
- Stamping today's date in lastmod on every page, changed or not.
- Forgetting to regenerate the file after adding a new service page.
- Expecting the sitemap to rescue an orphan page that no other page links to.
What does Pilotiko do with sitemaps?
For the business website it builds and hosts, Pilotiko generates the sitemap, the robots.txt file, structured data and an llms.txt file. Instant search engine notification through IndexNow is not offered yet.
Frequently asked questions
What is the difference between an XML sitemap and an HTML site map?
An XML sitemap is written for search engine crawlers as a structured list of URLs. An HTML site map is a page people can read. You can have both.
Do I have to submit my sitemap to Google?
It is not mandatory, because Google also discovers pages through links. Declaring it in robots.txt with a Sitemap: line lets any search engine find it.
Are priority and changefreq worth filling in?
The protocol makes both optional and describes changefreq as a hint. An accurate lastmod date is more useful than a priority picked at random.
Will a sitemap get my pages indexed?
Not on its own. Google is explicit that a sitemap does not guarantee every item will be crawled and indexed. Page quality and accessibility still decide.
How many URLs can one sitemap hold?
Up to 50,000 URLs and 50 MB uncompressed. Beyond that you split the list into several files tied together by a sitemap index.
Should French and English pages both be in the sitemap?
Yes, if both are meant to be indexed. A sitemap can also declare the language versions of a page, which is one of the ways to implement hreflang.
Sources
- Google Search Central, Learn about sitemaps (accessed on October 15, 2026).
- sitemaps.org, Sitemaps XML format (accessed on October 15, 2026).
- Google Search Central, In-depth guide to how Google Search works (accessed on October 15, 2026).
- Google Search Central, How to specify a canonical URL with rel="canonical" and other methods (accessed on October 15, 2026).
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