is an optional element in the . It indicates when a URL's main content last changed significantly and can serve crawlers as an update hint.

Examples:

  • <lastmod>2026-06-08</lastmod>
  • <lastmod>2026-06-08T13:45:00+02:00</lastmod>

The date should reflect only genuine content changes, such as new text, updated facts or changed prices. Minor adjustments like a changed footer year, a new tracking script or a pure deploy are not sufficient reasons.

A common mistake is the "always today" pattern: the sets every URL to the current date on each deploy. Then all pages look equally fresh and the signal loses value. A missing lastmod is less problematic than an incorrect one.