From July 1, 2019, Google’s mobile first indexing will become standard for new domains. Google defines new domains as “domains that have been previously unknown to Google Search”.
Mobile vs desktop
Mobile searches have experienced explosive growth in recent years. In fact, they have surpassed searches via desktop. That is why Google tries to encourage website owners to make their websites and content more mobile-friendly. Google’s indexing and ranking systems originally always looked at the desktop version of a website. However, this can cause problems when desktop sites and mobile sites have different versions of the content.
Mobile first indexing
Mobile-first indexing is not yet standard for all websites, but Google already started rolling out in 2018. Older websites are evaluated based on various factors:
For existing websites, we determine whether content is ready for mobile first indexing on the basis of content equality (including text, images, videos, links), structured data and other meta-data (titles, descriptions of robots meta tags). We recommend double-checking these factors when a website is launched or redesigned.
It is important to note that there is no separate “mobile first index”. Google still refers to a unified index for displaying search results. The difference is whether a page is crawled by a desktop or mobile user agent.
Individual mobile sites discouraged
Before responsive web design became the standard, it was common to have a separate mobile site. Although Google still supports this approach, they actively advise against it. This is because it often causes confusion, both for users and for search engines.
WordPress websites that use a responsive theme will not experience any problems with mobile indexing as long as they do not have their mobile websites on a separate domain. A responsive WordPress theme is usually sufficient to make a website compatible with this method of crawling.
If you’d like to know how your website is crawled, you can click on the URL Inspection tab in Google Search Console. Webmasters from older sites will receive a notification from Search Console when their sites are transferred to mobile-first indexing.