XML sitemaps are essential for every site’s SEO strategy and are a big part of our core Yoast SEO product. Both Google and Bing have recently renewed emphasis on properly using the lastmod (last modified) tag in XML sitemaps. The leading search engines now advise site owners to use this feature properly for better crawling and indexing.

What is the lastmod tag in XML sitemaps?

The lastmod tag in an XML sitemap indicates the last time a particular page on your website was updated. This information helps search engines understand which pages have fresh content and prioritize them for crawling.

The situation before

Before the recent emphasis from Google and Bing, using the lastmod tag was optional and often misused. Many site owners either ignored it or didn’t understand its proper use.

This led to inconsistencies in how search engines crawled and indexed updated content. Some site owners would incorrectly update the lastmod date every time the sitemap was regenerated, regardless of actual content changes, causing inefficiencies in crawling.

Recent advice from Google and Bing

Both Google and Bing have updated their guidelines to stress the importance of accurately using the lastmod tag.

• Google: Google’s latest guidelines emphasize that using the lastmod tag helps the search engine prioritize crawling and indexing pages with fresh content. In its XML sitemap documentation, Google says: “Google uses the <lastmod> value if it’s consistently and verifiably (for example, by comparing to the last modification of the page) accurate.”
• Bing: In February 2023, Bing also highlighted the critical nature of the lastmod tag in XML sitemaps, advising site owners to ensure this tag accurately reflects content updates.

A key reason behind this renewed focus is to improve crawl efficiency, contributing to a greener, more sustainable future. Efficient crawling reduces search engines’ computational resources, lowering their carbon footprint. By using the lastmod tag correctly, site owners can help search engines crawl their sites more efficiently, supporting environmental sustainability.

Why this matters for SEO

XML sitemaps are crucial for SEO because they help search engines efficiently discover and index your website’s content. Sitemaps list all your site’s pages, ensuring that crawlers don’t miss your important content.

The lastmod tag in sitemaps indicates when a page was last updated, helping search engines quickly re-crawl fresh content. This keeps your site’s information current in search results. Including new pages in your sitemap speeds up their indexing, improving your visibility.

Sitemaps are invaluable for large or complex websites. They help search engines navigate extensive content, and they can also include details about images, videos, and news articles, enhancing visibility in specialized search results.

XML sitemaps boost your SEO by ensuring search engines discover, crawl, and index your content efficiently. This leads to better visibility and higher rankings in search results.

With this latest news, lastmod becomes an ally for your SEO efforts:

1. Improved crawling efficiency: Accurate lastmod dates help search engines allocate their crawling resources more effectively, focusing on new and updated content.
2. Better indexing: Fresh content is more likely to be indexed quickly, improving your site’s visibility in search results.
3. Enhanced user experience: Keeping search engines updated with the latest content ensures that users find the most current information when they visit your site.

How to implement the lastmod tag correctly

Most XML sitemaps will probably already have a lastmod built-in. At Yoast, we help over 13 million sites with proper XML sitemaps built in the best possible way. If you’re using Yoast SEO, you can’t misuse lastmod because we update the XML sitemap for you, and don’t allow you to use it incorrectly.

In short, there are some best practices to keep in mind:

1. Update only when necessary: Ensure that the lastmod date reflects the actual last modification date of the page’s content.
2. Automate with care: Use automated tools to update your sitemap, but ensure they are configured correctly to update the lastmod tag only when the content changes.
3. Monitor and review: Regularly review your sitemap to ensure the lastmod dates are accurate and reflect genuine content updates.

Yoast SEO’s support for lastmod

Yoast SEO has always supported the lastmod tag in XML sitemaps. Our plugin automatically includes the lastmod tag for each page and post, ensuring that search engines are notified of the most recent updates.

• Automatic updates: Yoast SEO updates the lastmod tag whenever you update a post or page, taking the guesswork out of maintaining accurate sitemaps.
• User-friendly: By incorporating the lastmod tag seamlessly into its XML sitemaps, Yoast SEO makes it easy for site owners to follow best practices without needing technical expertise.

By using Yoast SEO, you can ensure your sitemaps are always up-to-date. This keeps you aligned with the latest recommendations from Google and Bing.

Conclusion to lastmod support by Bing and Google

Google and Bing’s renewed focus on the lastmod tag reminds site owners to adhere to best practices in sitemap creation and maintenance. Implement these recommendations and use tools like Yoast SEO to enhance your site’s SEO performance. This ensures search engines will discover and index your fresh content promptly.