---
title: "Sitemap freshness (lastmod) · Sitebulb Labs"
description: "<lastmod> lets an agent re-read only what changed instead of recrawling everything."
url: https://labs.sitebulb.com/docs/checks/discoverability/sitemap-lastmod/
---

# Sitemap freshness (lastmod)

\<lastmod> lets an agent re-read only what changed instead of recrawling everything.

- Category

  [Discoverability](https://labs.sitebulb.com/docs/checks/discoverability)

- Standard

  Recommended

## 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.

```xml
<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](https://labs.sitebulb.com/docs/checks/discoverability/sitemap).