Google has no plans to allow publishers to opt into or out of mobile-first indexing, explained Webmaster Trends Analyst John Mueller on the latest edition of #AskGoogleWebmasters.

The question. “Is there any plan to eventually let webmasters tell Google they want to be included in the mobile-first index or at least considered for inclusion? Some non-responsive sites might believe their mobile site is more SEO-friendly than the desktop site,” user @DanielM35110466 asked via Twitter.

The answer. “With the longer-term goal of moving all sites over to mobile-first indexing, we don’t plan to provide an opt-in or opt-out for this kind of indexing,” Mueller responded.

Although mobile-first indexing was originally announced in November 2016, it has not made its way to all sites. Mueller touched upon this, explaining “At the moment, we’re algorithmically testing to see when sites are ready and switching them over once that’s the case. To determine when a site is ready, we compare the mobile and the desktop versions to make sure that we’re still able to find all of the content, including structured data and images.”

“Mobile-first indexing is separate from mobile friendliness,” he also clarified. “Even sites that don’t have a mobile version at all can be indexed fine with the mobile Googlebot. Our goal is to use the mobile-first indexing for all websites in our search results.”

Why we should care. Not being able to opt into or out of mobile-first indexing means that we don’t get to dictate the conditions in which our sites are crawled and indexed, which, in turn, reflects the reality that we don’t get to choose what devices our visitors are using to access our sites.

Since Google’s goal is to use mobile-first indexing across the board, publishers should ensure that their mobile sites provide a fluid user experience and allow mobile visitors to access everything that desktop users can. This isn’t just important because Google prioritizes it — most users are now browsing via smartphones, and having a mobile-optimized site means you’re able to cater to the majority.

Learn more about mobile-first indexing. Here are some resources that can help you make the transition to mobile-first indexing as smooth as possible.