Sitemap freshness (lastmod)

What it checks

The extension fetches the first sitemap declared in robots.txt that is on the same site, or /sitemap.xml if none is declared. A sitemap hosted on another domain is not fetched. It counts the <url> and <sitemap> entries and how many of them carry a <lastmod> date. For a sitemap index, it counts the entries in the index itself; it does not open the child sitemaps.

Results

Status	When
Pass	Every entry in the sitemap has a <lastmod>
Warn	Some entries have a <lastmod> and some do not
Warn	No entry has a <lastmod>
N/A	No sitemap was found to inspect
N/A	robots.txt only lists sitemaps on other hosts

This is a bonus check: complete <lastmod> dates add points, and missing ones cannot lower the Discoverability score.

How to fix

Add a <lastmod> to each entry, set to the date the page’s content last changed in W3C Datetime format. Most CMS and static-site sitemap plugins can do this for you.

<url>
  <loc>https://example.com/pricing</loc>
  <lastmod>2026-09-01</lastmod>
</url>

Keep the dates honest. A <lastmod> that changes on every build tells an agent everything changed, which is no better than having none.

See also Sitemap available.

Support by agent and browser

Announced means the vendor’s own docs or announcement say so. Published is the date on the vendor’s own page, where it has one. Checked is the last time our weekly research found that page still saying so.

Agent	Status	Source
AI assistants
Copilot Microsoft	Supported (announced)	Keeping Content Discoverable with Sitemaps in AI Powered Search (Bing Webmaster Blog) Published 31 Jul 2025 · Checked 9 Oct 2026'The lastmod field in your sitemap remains a key signal, helping Bing prioritize URLs for recrawling and reindexing.' Recommends ISO 8601 with time, set to the page content's true modification time.

No evidence yet26

• ChatGPT
• Claude
• Gemini
• Perplexity
• Meta AI
• ChatGPT Atlas
• Comet
• Dia
• Gemini in Chrome
• Edge Copilot Mode
• Claude Code
• Cursor
• Codex
• GitHub Copilot
• Windsurf
• CCBot
• Applebot
• Amazonbot
• Bytespider
• Cohere
• Mistral
• DuckAssist
• Chrome
• Edge
• Firefox
• Safari

Names and marks belong to their owners and are used only to identify products. None of these vendors is affiliated with Sitebulb. Spotted something out of date? Send a correction.

Adoption on the top 100 sites

52%

51 of 99 measured sites implement it

Scanned 23 Oct 2026 with the Sitebulb Labs extension, against the Tranco list (tranco-56Z8N). 1 sites couldn’t be measured (bot challenge or timeout) and are left out of the share.

Sites implementing it51

1. #1 google.com (with warnings)
2. #2 cloudflare.com
3. #3 aws.amazon.com (via amazonaws.com)
4. #9 microsoft.com (with warnings)
5. #11 youtube.com (with warnings)
6. #12 apple.com (with warnings)
7. #20 dzen.ru (with warnings)
8. #24 azure.microsoft.com (via azure.com) (with warnings)
9. #32 github.com (with warnings)
10. #37 fastly.com (via fastly.net) (with warnings)
11. #42 bing.com (with warnings)
12. #43 netflix.com (with warnings)
13. #44 triplinkintl.com
14. #48 gandi.net (with warnings)
15. #50 marketingplatform.google.com (via doubleclick.net) (with warnings)
16. #53 icloud.com (with warnings)
17. #55 wordpress.org
18. #60 digicert.com (with warnings)
19. #61 adobe.com (with warnings)
20. #68 zoom.com (via zoom.us)
21. #71 endpoints.news
22. #75 roblox.com (with warnings)
23. #77 open.spotify.com (via spotify.com) (with warnings)
24. #85 ntp.org
25. #86 msn.com (with warnings)
26. #90 vimeo.com
27. #93 bunny.net (via b-cdn.net)
28. #96 f5.com (with warnings)
29. #101 wordpress.com
30. #106 sentry.io (with warnings)
31. #107 letsencrypt.org (via lencr.org)
32. #109 ui.com (with warnings)
33. #110 european-union.europa.eu (via europa.eu) (with warnings)
34. #116 bitly.com (via bit.ly)
35. #117 ipify.org
36. #120 samsung.com
37. #122 intuit.com (with warnings)
38. #127 openai.com (with warnings)
39. #131 pages.github.com (via github.io) (with warnings)
40. #132 dropbox.com (with warnings)
41. #135 discord.com (via discord.gg) (with warnings)
42. #136 developer.adobe.com (via adobe.io)
43. #140 android.com (with warnings)
44. #141 nih.gov (with warnings)
45. #151 archive.org
46. #153 webex.com (with warnings)
47. #154 snapchat.com (with warnings)
48. #158 kaspersky.co.uk (via kaspersky.com) (with warnings)
49. #159 firebase.google.com (via crashlytics.com)
50. #160 tumblr.com (with warnings)
51. #161 nytimes.com

Overview

7/9

Gaining traction

Real support exists and adoption is growing.

How this rating is worked out7 of 9 points

Factor	Points	Why
Vendor support	1 / 3	1 vendor supporting, 0 partly or planned
Top-100 adoption	3 / 3	52% of measured sites
Spec maturity	3 / 3	Published standard

8 or more points is Established, 5 to 7 is Gaining traction, 2 to 4 is Speculative and under 2 is Stalled. A feature is also Stalled when more vendors have said no than yes. Read the spec.

Community insights

No community insights for this feature yet.

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