Are your sitemap dates telling the truth?
Crawlers use lastmod to decide what to recrawl. A future date, an invalid date, or one identical value across the whole site is worse than none — the crawler learns to ignore it.
Reads the lastmod values in your sitemap. Nothing is stored.
How this check works
Shipwork reads /sitemap.xml, follows up to three child sitemaps when it is an index, and checks the lastmod values: are they valid dates, are any in the future, is one value reused across the whole site, and how old is the newest. Wrong values are worse than none.
Questions
- What format should lastmod be?
- A W3C datetime: 2026-09-20 or 2026-09-20T10:00:00+00:00. Anything else may be ignored.
- Why is a future date a problem?
- Crawlers treat a lastmod in the future as unreliable and may ignore all your lastmod values as a result.
- Should every URL have the same lastmod?
- No. One value across the whole site is a weak signal that the date is not real. Set it per page, or omit it.