XML Sitemaps: How They Work & Validation

A sitemap is a roadmap for search engines. It lists your pages, tells crawlers when they were last updated, and hints at their relative importance.

You don’t strictly need a sitemap—search engines can find pages by following links. But sitemaps make discovery faster and give you more control over how your site gets crawled.

What’s in a Sitemap

An XML sitemap follows a standard format:

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://example.com/</loc>
    <lastmod>2026-02-08</lastmod>
    <changefreq>weekly</changefreq>
    <priority>1.0</priority>
  </url>
  <url>
    <loc>https://example.com/about</loc>
    <lastmod>2026-01-15</lastmod>
    <changefreq>monthly</changefreq>
    <priority>0.8</priority>
  </url>
</urlset>

Sitemap Elements

Element	Required	Purpose
`<loc>`	Yes	The full URL of the page
`<lastmod>`	No	When the page was last modified
`<changefreq>`	No	How often the page changes (hint only)
`<priority>`	No	Relative importance (0.0-1.0)

Google officially ignores changefreq and priority. But lastmod is useful if accurate—it helps crawlers know which pages to re-check.

When Sitemaps Matter Most

Sitemaps are especially important for:

Large Sites

Sites with thousands of pages can’t rely on link-based discovery alone. A sitemap ensures nothing gets orphaned.

New Sites

New domains don’t have inbound links yet. A sitemap submitted to Google Search Console jumpstarts indexing.

Sites with Poor Internal Linking

If pages are buried deep or not well-linked, sitemaps help crawlers find them.

Frequently Updated Content

News sites and blogs benefit from lastmod dates that signal fresh content.

Sitemap Best Practices

One Sitemap or Many?

Large sites split sitemaps using a sitemap index:

<?xml version="1.0" encoding="UTF-8"?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <sitemap>
    <loc>https://example.com/sitemap-posts.xml</loc>
    <lastmod>2026-02-08</lastmod>
  </sitemap>
  <sitemap>
    <loc>https://example.com/sitemap-products.xml</loc>
    <lastmod>2026-02-07</lastmod>
  </sitemap>
</sitemapindex>

Each individual sitemap can contain up to 50,000 URLs and must be under 50MB uncompressed.

Reference in robots.txt

Tell crawlers where to find your sitemap:

User-agent: *
Allow: /

Sitemap: https://example.com/sitemap.xml

Use Accurate lastmod Dates

Only update lastmod when content actually changes. If you regenerate the sitemap daily with today’s date on every page, the signal becomes meaningless.

Only Include Canonical URLs

Don’t include:

URLs that redirect
Non-canonical versions (with trailing slashes, query parameters, etc.)
Pages blocked by robots.txt
Pages with noindex meta tags

Common Sitemap Problems

Invalid XML

XML parsing is strict. Common errors:

<!-- Missing closing tag -->
<url>
  <loc>https://example.com/page

<!-- Unescaped ampersand -->
<loc>https://example.com/?a=1&b=2</loc>

<!-- Should be: -->
<loc>https://example.com/?a=1&amp;b=2</loc>

Wrong Namespace

The namespace declaration must be exact:

<!-- Correct -->
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">

<!-- Wrong - will fail validation -->
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap">

URLs Not Matching Domain

All URLs must match the sitemap’s domain:

<!-- sitemap at https://example.com/sitemap.xml -->

<!-- Valid -->
<loc>https://example.com/page</loc>

<!-- Invalid - different domain -->
<loc>https://other-domain.com/page</loc>

<!-- Invalid - different protocol -->
<loc>http://example.com/page</loc>

Unreachable URLs

Every URL in your sitemap should return a 200 status. Including 404s or 500s wastes crawl budget and signals poor quality.

Outdated Sitemap

Static sitemaps that aren’t updated become useless. If you add pages but never update the sitemap, new content won’t be discovered through it.

Dynamic Sitemap Generation

Most CMS platforms and frameworks generate sitemaps automatically:

WordPress

Plugins like Yoast SEO or Rank Math generate and update sitemaps automatically.

Static Site Generators

Astro: @astrojs/sitemap integration
Next.js: next-sitemap package
Hugo: Built-in sitemap generation
Gatsby: gatsby-plugin-sitemap

Custom Solutions

For dynamic sites, generate sitemaps from your database:

// Pseudocode
async function generateSitemap() {
  const pages = await db.query('SELECT url, updated_at FROM pages WHERE status = "published"');

  const xml = pages
    .map(
      (page) => `
    <url>
      <loc>${page.url}</loc>
      <lastmod>${page.updated_at.toISOString()}</lastmod>
    </url>
  `
    )
    .join('');

  return `<?xml version="1.0" encoding="UTF-8"?>
    <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
      ${xml}
    </urlset>`;
}

Validating Your Sitemap

Before submitting to search engines, validate that your sitemap:

Is valid XML: Parses without errors
Uses correct schema: Proper namespace declaration
Contains valid URLs: All URLs are reachable
Has reasonable lastmod dates: Not all in the future or distant past
Doesn’t exceed limits: Under 50,000 URLs and 50MB

Our Sitemap Validator checks all of this automatically:

Fetches and parses your sitemap
Validates XML structure
Counts URLs and checks for the 50,000 limit
Identifies malformed entries
Checks for common issues

It’s free and gives you a clear picture of your sitemap’s health.

Submitting to Search Engines

Google Search Console

Go to Search Console
Select your property
Navigate to Sitemaps
Enter your sitemap URL
Click Submit

Google shows submission status, crawl results, and any errors discovered.

Bing Webmaster Tools

Similar process—submit in the Sitemaps section.

Direct Ping

You can also ping search engines directly:

https://www.google.com/ping?sitemap=https://example.com/sitemap.xml
https://www.bing.com/ping?sitemap=https://example.com/sitemap.xml

Monitoring Sitemap Performance

In Google Search Console, the Sitemaps report shows:

Last read date
Status (success/error)
Discovered URLs
Indexed URLs (via the Pages report)

If “discovered” is much higher than “indexed,” investigate why pages aren’t being indexed.

Sitemaps vs. Internal Linking

Sitemaps don’t replace good internal linking. They complement it:

Internal links: Tell crawlers (and users) how pages relate
Sitemaps: Ensure comprehensive discovery

A page linked from your homepage will likely be found without a sitemap. An orphaned page deep in your archive needs the sitemap.

Take Action

Check if your sitemap exists at /sitemap.xml
Run it through our Sitemap Validator
Fix any issues
Submit to Google Search Console if you haven’t already
Reference it in your robots.txt

For help with sitemap configuration or SEO strategy, reach out.