Google Senior Webmaster Trends Analyst John Mueller said in a discussion on Reddit this week that Google uses other criteria besides mobile-friendliness in deciding if a website is ready to be moved to mobile-first indexing.
Google uses different bots to crawl sites in the mobile-first index vs. the regular index.
If your website has been moved to the mobile-first index, Google should have notified you of that by e-mail.
If your website is still in the regular index, that could be because:
- Google finds your site not to be mobile-friendly. You can easily check on that by running Google's Mobile-Friendly Test on your website.
- Your site doesn't show identical content - or at least important content - to all users
- Structured data appears on desktop pages but not on mobile
- Fewer images are shown to mobile users
- Broken or fewer internal links on mobile devices
For a quick - but thorough - check on all those items, try the Mobile-First Index Tool here: https://technicalseo.com/tools/mobile-first-index/ which looks like this:
Just enter your primary or desktop URL, select a crawler from the User Agents dropdown - you have choices of Googlebot Regular vs. Smartphone, Chrome Windows vs. Android or SEO Spider Regular vs. Mobile.
The tool then produces in great detail several Desktop vs. Mobile Reports:
- Google Tests
- Structured Data
Is your website ready for mobile-first indexing?
Use this nice, free tool to find out.