# Sitemap validity

> Sitemap validity is whether a sitemap is well-formed XML with correct URLs that actually load.

- **Check ID:** SM3
- **Area:** [Tech Stack](https://be1st.ai/glossary/fingerprint)
- **Tool:** [Tech Stack](https://be1st.ai/tools/tech-stack)
- **Page:** https://be1st.ai/glossary/fingerprint/sitemap-validity

## Why it matters

An invalid sitemap can cause crawlers to ignore it. Incorrect URLs, missing namespaces, or invalid dates lead to indexing errors. Up-to-date lastmod dates help crawlers re-crawl efficiently.

## In practice

A sitemap with URLs pointing to 404 pages signals a neglected website. A sitemap without lastmod dates doesn't allow crawlers to distinguish new from old content. A valid sitemap with current dates speeds up indexing.

## How be1st checks it

Verification of sitemap XML format, URL correctness, and accessibility of linked pages. Checks lastmod dates, changefreq, and priority attributes.

[Tech Stack](https://be1st.ai/tools/tech-stack), Site files tab.

## Sources

- [Sitemaps XML Format](https://www.sitemaps.org/protocol.html) (sitemaps.org)

## Related terms

- [SSL certificate existence](https://be1st.ai/glossary/fingerprint/ssl-certificate-existence): An SSL/TLS certificate is the digital certificate that lets a website use HTTPS and proves to browsers that the domain is genuine.
- [SSL certificate issuer](https://be1st.ai/glossary/fingerprint/ssl-certificate-issuer): The certificate issuer is the certificate authority that signed a website's SSL certificate, such as Let's Encrypt, DigiCert or Sectigo.
- [SSL certificate validity](https://be1st.ai/glossary/fingerprint/ssl-certificate-validity): Certificate validity is the period an SSL certificate is valid for. After its expiry date, browsers show visitors a security warning instead of the site.
- [Vector embeddings](https://be1st.ai/glossary/fingerprint/vector-embeddings): A vector embedding is a list of numbers that represents the meaning of a text, so texts with similar content end up close to each other.
- [Competitor similarity](https://be1st.ai/glossary/fingerprint/competitor-similarity): Competitor similarity is how close the content of two websites is, measured by comparing their vector embeddings.
- [CMS / content management system](https://be1st.ai/glossary/fingerprint/cms-content-management-system): A CMS (content management system) is the software a website is built and edited in, such as WordPress, Drupal or Joomla.