Google has already enabled mobile-first indexing—using the mobile version of the content for indexing and ranking—by default for all new websites, since mid-2019. For older websites, it’s still continuing to monitor and evaluate pages, and Googlebot will primarily crawl and index pages with the smartphone agent going forward.
Google Search now uses only one index; there isn’t a separate mobile-first index any more.
Earlier, the Google index used the desktop version of a page’s content for evaluating the relevance of a page to a user’s query. As it switches more existing sites to mobile-first indexing, publishers may lose traffic if the mobile versions of their sites are not compliant with Google’s mobile-first indexing best practices.
This week, the company announced some significant updates to its guidelines on mobile-first indexing, which it advises site owners to check out “whether your site has been moved over already or not.”
It’s important that publishers are well-versed with these updated guidelines, especially those with older sites.
For example, Google asks to “make sure that your mobile site contains the same content as your desktop site.” If the mobile site has less content than the desktop site, Google advises updating the mobile site so that its primary content is equivalent to the desktop site, since “almost all indexing on your site comes from the mobile site.”
The guidelines have some “stern” warnings (like below) making it clear that traffic loss probability becomes quite high when the advised parameters are not met.
There are a number of such best practices detailed in the updated guide, covering content, metadata, structured data, ads placement, visual content, videos and URLs.
More than half of the web traffic worldwide comes through mobile devices, so mobile focus can no longer be an afterthought for publishers.
While publishers cannot opt into or out of mobile-first indexing, it’s quite simple to find out whether or not a website has been moved over.
Site owners are updated via Google’s Search Console (GSC) when their site is switched to mobile-first indexing. The URL Inspection Tool in the GSC can be used to check how Google last crawled the domain, by looking at the ‘Crawled as’ section.
If it shows “Googlebot smartphone,” that means the site has been moved over to mobile-first indexing. Otherwise, “Googlebot desktop” indicates the switchover is still pending.
It’s important to note that mobile-first indexing only affects a site if it has separate desktop and mobile pages. Responsive websites are basically unaffected by the change, making it the best option for publishers going forward, rather than maintaining different mobile and desktop alternatives.