Introduction to Bing’s Sitemap Guidance
Bing has recently updated its guidance on sitemaps, placing a strong emphasis on the lastmod tag. This update is crucial for AI-powered search, as it helps determine which pages need to be recrawled. While tools like IndexNow offer real-time updates, accurate lastmod values are essential for keeping content discoverable, particularly on large or frequently updated sites.
The Importance of Lastmod for Recrawling
Bing highlights that the lastmod field in a sitemap is a top signal for AI-driven indexing. It assists in determining whether a page needs to be recrawled or can be skipped. To use this effectively, it’s recommended to use the ISO 8601 format with both date and time. This level of precision helps Bing prioritize crawl activity based on actual content changes. It’s also important to avoid setting lastmod to the time the sitemap was generated unless the page was truly updated. Additionally, Bing has confirmed that changefreq and priority tags are no longer considered when it comes to crawling or ranking.
Submission and Verification Tips
For effective sitemap submission, Bing recommends two methods: referencing the sitemap in the robots.txt file or submitting it via Bing Webmaster Tools. Once submitted, Bing immediately fetches the sitemap and rechecks it daily. To verify if the sitemap is working, users can check the submission status, last read date, and any processing errors in Bing Webmaster Tools.
Combining Sitemaps with IndexNow
To enhance the chances of timely indexing, Bing suggests combining sitemaps with IndexNow. While sitemaps provide a comprehensive view of a site, IndexNow allows for real-time URL-level updates, which is particularly useful for content that changes frequently. By combining these tools, users can provide a strong foundation for keeping their content fresh, discoverable, and visible.
Sitemaps at Scale
For large websites, understanding Bing’s sitemap capacity limits is crucial. These limits include up to 50,000 URLs per sitemap, 50,000 sitemaps per index file, 2.5 billion URLs per index, and support for multiple index files to index up to 2.5 trillion URLs. This scalability makes the standard sitemap protocol suitable even for enterprise-level platforms. Using these limits to their full extent helps ensure that content remains discoverable in AI search.
Why Accurate Sitemaps Matter
As search becomes more AI-driven, accurate crawl signals become more important. Bing’s reliance on sitemaps, especially the lastmod field, shows that basic technical SEO practices remain vital, even as AI changes how content is surfaced. For large sites, Bing’s support for trillions of URLs offers scalability, while for everyone else, the key message is to keep sitemaps clean, accurate, and updated in real-time to give content the best chance at visibility in AI search.
Conclusion
In summary, Bing’s updated guidance on sitemaps underscores the significance of the lastmod tag for AI-powered search. By following Bing’s recommendations on sitemap submission, combining sitemaps with IndexNow, and understanding the capacity limits, users can improve the discoverability of their content. As search continues to evolve with AI, adhering to these guidelines will become increasingly important for maintaining content visibility. Therefore, it’s essential for website owners and managers to prioritize accurate and up-to-date sitemaps as part of their SEO strategy.