Google Mobile-First Indexing Explained

Recently, Google announced that mobile-first indexing is now the default method for crawling websites. Concurrently, Google added further notifications about your site’s status in regards to mobile first indexing, including the date your site was moved to mobile first indexing (Google began moving sites to mobile-first towards the end of 2018). It’s self-explanatory that Google is now looking more closely at your mobile website, but what does it ultimately mean for SEO? Thankfully, there are only a few key components to understand what mobile-first indexing means to your site.

Mobile Friendly

First and foremost, you’ll want to make sure your site is mobile-friendly! While optimizing your mobile experience should be a continuous focus, you’ll want to ensure Google deems your site what it considers to be “mobile friendly.” For Google, “mobile friendly” means users can access and use the site on a smartphone without difficulty (as opposed to the poor experience of trying to navigate a desktop site on a mobile device).

In Google Search Console under the “Enhancements” section, the “Mobile Usability” tab will report any issues with the mobile version of your site. Errors in this report are related to issues that prevent users from easily accessing your site, including: text too small to read, clickable elements too close together, or content wider than screen. Conveniently, Google Search Console allows you to test and render pages on demand, so any issues you find can quickly be confirmed with Googlebot’s render of the page. In addition to the negative SEO ramifications, mobile experience issues like these should be immediately addressed to prevent any issues with conversion rates.

Mobile usability errors on your site should be fixed as quickly as possible

Beyond confirming your site’s mobile friendliness and its ability to handle traffic, it’s important to understand what kind of mobile site you have. Responsive site designs have become very prominent. A responsive site is a website with one source code that serves an extremely similar experience that adjusts based on the screen size of the device. An easy way to test whether or not a site is responsive is to load the website on a desktop device and then resize your browser window and observe if the site renders again to fit the updated window size. The primary advantage of a responsive site is that it requires only one set of code to manage and eliminates the possibility of inconsistencies between the mobile and desktop site. When it comes to the shift to mobile first indexing, fully responsive sites are oftentimes properly configured to handle the change by default.

If you host your mobile site at a separate subdomain (frequently an “m.” site), you’ll need to strive for consistency between your mobile and desktop sites. In addition to making sure your desktop site’s content is fully available on your mobile site, confirm that your site’s metadata and structured markup is also in your mobile site’s source code. Proper canonical tags in this situation are of extreme importance, so make sure you properly configure your mobile pages to canonicalize to the mobile version of the page while your desktop pages should reference the mobile site as an alternate URL. On the Google side of things, confirm that both the desktop and mobile versions of your websites are verified properties on Search Console. While a separate mobile site requires more oversight to maintain, it is still a viable option as long as it is properly configured.

Mobile Performance & Testing

A performance test can determine whether your site is able to properly handle your site’s traffic

Google has measured site speed as a ranking factor for several years, and the move to mobile-first indexing means that the speed of your mobile site is now tied to your organic ranking. In addition to running speed tests on the mobile version of your site (performance between your desktop and mobile sites can greatly vary, so be sure to test both) consider running a performance test with Taistech to determine whether your website is equipped to effectively handle your site’s traffic. While slow websites can sometimes rank well despite slower speeds, there is no doubting the negative impact a slow website can have on both bounce rates and conversion rates.

Once the technical aspects of your site are squared away, it can be easy to forget that Google (not to mention the majority of your users) are accessing the mobile version of your website. When testing your website and evaluating user experience, prioritize the mobile version of your website. Beyond it being the basis of your organic rankings, your mobile site will only continue to increase its share of your overall traffic as time progresses and mobile browsing becomes more prominent. With mobile sessions that are usually shorter in length and feature higher bounce rates, winning organic mobile traffic means nothing if these sessions end without any conversions.

Given how different the experience can change between desktop and mobile (even if the same content is presented in a different format), tracking your performance should always be segmented between desktop and mobile devices. Engagement and conversion rates can vary drastically as can your organic rankings, so optimizing for both experiences regardless of how Google sees your site is crucial to maintaining a successful site.


As Google continues to evolve and reevaluate how it crawls and indexes the web, an overarching theme of favoring usability and experience has emerged. The move towards mobile-first indexing is another sign of this—now that that the majority of users view sites on mobile devices, why wouldn’t Google as well? Though the mobile-first index change seems like an additional complication to the already confusing world of SEO, focusing on your mobile site’s performance and user experience should already be a priority. 

about Chris Brown

Chris Brown has nearly 20 years of retail leadership while driving impressive results in a diverse range of retail business models including, pure play ecommerce, brick and mortar, omnichannel (with substantial mobile expertise) and merchandising.   As Vice President of Omni-channel and eCommerce Strategy, Chris connects with clients to help drive their digital strategy, combining his experience in high-growth retail environments with software solutions to build revenue, increase conversion and drive retention.    Connect with Chris on Linkedin: linked button