How Does Google Manage Cache When Indexing Pages? (Crawling December: HTTP Caching)
Google has published new guidance on effective cache (cache) management in the process of indexing web pages. The article highlights how servers can work with Google's bots to optimise crawl time and improve site performance.
Key Points of the Recommendation
1. Handling HTTP Headers
Google recommends using headers that help bots determine whether a page's content has changed:
- ETag and If-None-Match: The preferred method for verifying content changes. The server returns an ETag header, and subsequent requests use If-None-Match.
- Last-Modified and If-Modified-Since: An older method based on the file's modification date. Google suggests using it together with ETag.
2. Cache-Control: Max-Age
Setting the Cache-Control header with a max-age value lets the server specify how long the content stays unchanged. Example:
3. Formatting the Date in Last-Modified
If you use Last-Modified, remember to use the standard HTTP date format:
Verifying Google Crawlers
To make sure traffic comes from official Google bots, take three steps:
- Check the User-Agent, which identifies Googlebot.
- Verify the IP address: check whether it belongs to Google's IP range.
- Use reverse DNS: the host should match the *.googlebot.com pattern.
Why Does This Matter?
Correct header configuration saves server resources and speeds up the indexing of key changes on your site. As a result, it improves your website's visibility in search results.
Summary
Google's new recommendations are a step towards better server resource optimisation and more efficient page indexing. Implementing HTTP headers such as ETag, along with proper Cache-Control configuration, will help your site run faster and more effectively. Cache header settings usually sit with the technical team, which is why an SEO agency implements these recommendations together with developers.
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