It's been two years since we started working on "mobile-first indexing" - crawling the web with smartphone Googlebot, similar to how most users access it. We've seen websites across the world embrace the mobile web, making fantastic websites that work on all kinds of devices. There's still a lot to do, but today, we're happy to announce that we now use mobile-first indexing for over half of the pages shown in search results globally.
Checking for mobile-first indexing
In general, we move sites to mobile-first indexing when our tests assure us that they're ready. When we move sites over, we notify the site owner through a message in Search Console. It's possible to confirm this by checking the server logs, where a majority of the requests should be from Googlebot Smartphone. Even easier, the URL inspection tool allows a site owner to check how a URL from the site (it's usually enough to check the homepage) was last crawled and indexed.
If your site uses responsive design techniques, you should be all set! For sites that aren't using responsive web design, we've seen two kinds of issues come up more frequently in our evaluations:
Missing structured data on mobile pages
Structured data is very helpful to better understand the content on your pages, and allows us to highlight your pages in fancy ways in the search results. If you use structured data on the desktop versions of your pages, you should have the same structured data on the mobile versions of the pages. This is important because with mobile-first indexing, we'll only use the mobile version of your page for indexing, and will