Caching
Caching is an action taken by Google and other search engines, where they store a static compressed version of a page as well as files including CSS and JavaScript, to reduce the need to continuously fetch them. As caching is a complex topic there is a lot of information provided by Google to help further understand it, our Hangout Notes cover these insights along with actionable recommendations.
The cached version of a web page has no impact on Google Search and Top Stories
Web cache is just a convenience feature. As long as your content appears in the rendered HTML, it doesn’t matter for search purposes whether it’s in the web cache.
Check Cached Page to See if Redirect Has Been Picked up by Google
Check if Google has switched the canonical version after a redirect by seeing if the cached version of the page is the target page. You can also use the GSC URL Inspection Tool to check the canonical version.
Google’s Cached Version of a Page Can be Out of Sync With Live Page
Google’s cached version of a page isn’t exactly what is used for indexing and can, sometimes, be a bit out of sync with the live page. Also, the cached date doesn’t reflect the last time that Googlebot crawled the page.
ETags & If-Modified-Since Headers Can Improve UX Due to Caching Functionality
Google doesn’t always use ETags and If-Modified-Since HTTP headers when crawling as not many sites use them and often get them wrong. However, they can impact UX because they can improve caching of resources for returning users.
ETags & If-Modified-Since Headers Can Improve UX Due to Caching Functionality
Google doesn’t always use ETags and If-Modified-Since HTTP headers when crawling as not many sites use them and often get them wrong. However, they can impact UX because they can improve caching of resources for returning users.
Google Caches CSS & JS Files so Doesn’t Need to Continuously Fetch Them
Google caches things like CSS files so that it doesn’t have to fetch them again in the future. Combining multiple CSS files into one can help Googlebot with this process, as can minifying JavaScript.
Google Cache Shows Static HTML, Not JavaScript Rendered HTML
Google cache shows the static HTML version of a page, so if the whole page is built using JavaScript, it may not be shown in the cache.
404 Cached Pages Can Occur After Site Switched to Mobile-first Indexing
Cached pages returning 404s can be a problem on Google’s side rather than an issue with crawling and indexing. This can happen when sites are moved to mobile-first indexing, as they tend not to have a cached page.
Google Recrawls Indexed AMP Pages to Update Cache
If Google find an AMP page that has already been indexed, a recrawl of that page will be triggered after a period of time to update the AMP cache.
Avoid Hosting Content Externally for CDNs
You should host as much of your content as you can on your domain when utilising a CDN because if you host content externally and want to change providers, you have no control over setting up redirects for migrating the content.