Google has recently updated its crawler documentation to provide more detailed insights into caching mechanisms and their impact on crawling efficiency. This update is designed to help SEOs and publishers optimize their websites for Google’s crawlers and reduce unnecessary server load.
A key recommendation from Google is the implementation of HTTP caching headers, particularly ETag and If-None-Match. These headers signal whether content has changed since the last crawl, allowing Google’s crawlers to avoid re-fetching unchanged content. By reducing unnecessary requests, this approach can significantly improve crawling efficiency and conserve server resources.
Google strongly advocates for the use of ETag over Last-Modified due to its greater accuracy and flexibility. ETag is less susceptible to errors related to date formatting, ensuring more reliable content validation. Additionally, if both headers are present, Google’s crawlers prioritize ETag in their caching decisions.
It’s important to note that different Google crawlers have varying levels of support for caching. While Googlebot, the primary crawler for Google Search, supports caching for re-crawling, other crawlers like Storebot-Google have more limited caching capabilities.
For those seeking to implement these recommendations, Google suggests consulting with hosting providers or CMS administrators. Additionally, setting the max-age field in the Cache-Control header can provide further guidance to crawlers on when to re-crawl specific URLs.
By following Google’s updated crawler guidance and effectively utilizing HTTP caching headers, SEOs and publishers can enhance their website’s performance, reduce server load, and improve their overall search visibility.
Google has also published a brand new blog post:
Crawling December: HTTP caching
Read the updated documentation:
HTTP Caching