Just about two years after Google announced their mobile-first indexing initiative, to crawl the web as a mobile device first versus crawling the web as a desktop device, Google hit a major mile stone. Over 50% of the search results Google returns globally are from Google crawling and indexing the web using mobile-first indexing.
Google's John Mueller said on the blog post "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."
Honestly, I am a bit surprised we are at over 50%. Keep in mind, this is not 50% of Google's index, it is 50% of the search results they show when searchers go to Google.com and type in a query. That is a big difference.
Just to be clear, this site is not yet done over mobile-first indexing I suspect because we use dynamic serving and not responsive design. The mobile version of this site, at least in terms of navigation, is pretty different.
This site did not receive a notification in Google Search Console yet and I used the URL inspection tool and it clearly says crawled as "Googlebot desktop" yesterday:
In the blog post, Google discussed how to tell if your site is moved over to mobile first indexing. In short, you'd get a notification, you can use the URL inspection tool as I showed above, you can check the server logs, where a majority of the requests should be from Googlebot Smartphone.
Google also warns about being careful with missing structured data on mobile pages and missing alt-text for images on mobile pages.
Those two specific tips are given in Google's blog post, likely for a good reason.
Congrats Google on making it to half way there in two years.
Forum discussion at Twitter.