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.
Google’s Cache Isn’t an Accurate View of Googlebot Rendering
The Fetch & Render tool in GSC and the Mobile-friendly Test tool show a more accurate view of how Googlebot is able to render a page than Google’s cache view, as this can easily be broken.
Google Cache Uses Non-Rendered HTML
If you use JavaScript to serve a mega menu, be aware that it might not show correctly in the cached version of a page because this uses the HTML rather than the rendered version. This doesn’t mean Google isn’t indexing the JavaScript-powered content.
Google Crawls AMP Pages to Validate & Cache Them
Google crawls AMP pages to check they are valid with a canonical tag back to the webpage, and also to be able to show them in the AMP cache.
Some Features in Organic Search Require AMP For Security Reasons
A number of search features require AMP to work well e.g. news carousel. For these search features it isn’t enough to have a mobile-friendly website as Google can’t serve your content from Google.com’s cache for security reasons.
Google Doesn’t Cache Pages With Server Errors
Googlebot doesn’t cache pages which return a server error, so it wouldn’t be possible to see what Googlebot saw in the GSC errors report.
Google Isn’t Always Able to Show Cached Versions of a Page
Google is unable to show the cached version of a page if it has a noarchive tag, or any JavaScript based content which isn’t included in the cache.
Empty Cached Pages Can Appear For JavaScript Sites
Google’s cached page usually reflects the raw HTML. For JavaScript based sites, if the JavaScript doesn’t run when it’s shown on the caching URL, then the cached version could appear empty.
Google Can Struggle Showing Cached Version of Pages With JavaScript
For cached pages if a site is using JavaScript, Google will link to those JavaScript files from the cached HTML page. However, because of cross-origin browser protections JavaScript won’t work in the same way if fetching it from a URL as opposed to directly from a website. So with some types of JavaScript if it can’t run for security reasons within the browser on a different domain, then it won’t work for a cached page.