Use View Source or Inspect Element to Ensure Hidden Content is Readily Accessible in the HTML
If you have content hidden behind a tab or accordion, John recommends using the view source or inspect element tool to ensure the content is in the HTML by default. Content pre-loaded on the HTML will be treated as normal content on the page, however, if it requires an interaction to load, Google will not be able to crawl or index it.
“Discovered Not Indexed” Pages May Show in GSC When Only Linked in Sitemap
Pages may show as “Discovered Not Indexed” in GSC if they have been submitted in a sitemap but aren’t linked to within the site itself.
Google Checks Status Code Pages Before Attempting to Render
Google checks the status code of a page before doing anything else, such as rendering content. This helps to identify which pages can be indexed and which pages it shouldn’t render. For example, if your page returns a 404, Google won’t render anything from it.
Only One Version of Same Content On Different Country Sites will be Indexed & Appear in GSC Performance Reports
If you have the same content on multiple language variation sites, Google will pick one to index but will use hreflang attributes to swap out versions of the page based on a user’s location. However, only the page that has been chosen to be indexed, and used as the canonical, will be displayed in the GSC performance report.
Speed is Critical For Google to Index Content Quickly
In order to index content quickly, for example news articles, Google need to be able to crawl the pages quickly. This includes being able to access the server quickly, with pages also loading quickly.
Google Does Not Index 404 Pages
If a page returns a 404 error code, Google will not index the page’s content. However, if the page has recently become a 404 page and Google has not crawled the page to see this, the page will still appear in search results. This error could also occur if the server displays a 404 page, but the code shown to crawlers is still a 200 status.
Signals Are Kept For 4xx or 5xx Error Pages Previously Dropped from the Index When They Are Re-added
If your pages displayed a 4xx or 5xx error for a while and were dropped from the index but become available again after a month or so, for example, Google will be able to return them to the search results in the same state they were before. They won’t have to start trying to rank from nothing.
Likely That Content Won’t Be Indexed if Not Showing Up in Google Testing Tools
If Google’s testing tools are able to fetch all of the different resources for a page, but there is content missing in the rendered output, it is likely that this content won’t be able to be indexed.
More or Less Every New Website is Rendered When Google Crawls it For the First Time
Nearly every website goes through the two waves of indexing when Google sees it for the first time, meaning it isn’t indexed before it has been rendered.