Google declared that its “Mobile-first index” for few sites and is closely supervising the sites for proper testing.

How to know your site has been moved under Mobile-first index?

You will get to see an increased in crawling rate through the Smartphone Googlebot present in the log files and the respective snippets in the results. Google cache pages will display the content that will be of mobile version only.

See some tips to make yourself mobile-first index ready

• The data on the mobile version should be of high-quality that includes text, images, videos etc.
• A structured data is essential that is present on both mobile and desktop. The URLs should be the updated one.
• Metadata is required on both mobile and desktop versions. It gives a brief about the type of content present on the mobile version.
• The sites that are specifically using mobile URL should have link rel=canonical and rel=alternate.
• Hreflang link should be checked on different mobile URLs. Using this link for internationalization, there is separate URLs link between mobile and desktop.
• Have a look at the servers and whether they can handle the increased crawl rate which is only meant for the mobile version.