Mobile-First Indexing : How Does it Impact SEO?

Mobile-First Indexing : How Does it Impact SEO?

In this article, we will explain what mobile-first indexing is and how to check if your resource is indexed. We will also provide a checklist on how to prepare a site for mobile-first indexing and explain how a new algorithm will influence SEO.

Mobile-first indexing – what is it and how does the algorithm work?

On November 4, 2016, it was announced in Google’s official blog that a new indexing algorithm appeared. Since then, priority has been given to the sites that are optimized for being shown in the mobile-first index. This is linked to an active increase in mobile traffic as more and more users are scouring the web on their smartphones. Let us have a look at the table comparing the data from 2016-2020, as well as predictions for 2021.


Based on the data collected, the introduction of new ranking algorithms was quite predictable from the search engine.

Now, let’s discuss the term mobile-first indexing, it means that the sites that are adapted for mobile devices will be ranked higher in the search system. Google does not create a separate index for platforms with an adaptive design. If a site has two versions, the priority during indexing will be given to the mobile version. If it is absent, then the search robot will return to the desktop version and will crawl it.

Here is what Fan Zhang, a Google software development engineer, has written in regard to this on the official search engine blog:

Webmasters Google

“The algorithm is intended to improve the quality of the mobile search results for users. Initially, for indexation and evaluation of the relevance, a desktop version was used. But now, the priority is given to the mobile version. If it is considerably different from a desktop one, it can worsen the site result.”

If a site has two equal mobile and desktop versions, in theory, the new algorithm won’t be able to influence the results of the ranking. Also, the availability of adaptive design would be a plus.

If a separate mobile web resource is available, it is better to set switchboard tags. They will point to the availability of the mobile URL’s thanks to the rel=alternate tag. In this case, the search robot won’t need to crawl and cache mobile pages, it will show the mobile URL for smartphones and other devices at the same time.

The transition of sites to the mobile-first indexing will not be finished until September 2020, according to the announcement on Google’s official blog.

Webmasters Google

According to the official representatives of Google, more than 70% of platforms have already been indexed.

After a domain transitions to the mobile-first indexing, the Googlebot’s activity will increase, and the mobile website will appear in the search engine index.

In an official interview, Martin Splitt stated that there it is not possible to speed up the process. Google cannot tell when this transition will be over, however, it will happen. It was also mentioned that the owners of sites cannot refuse from indexation, which is why they must adapt.

The information mentioned above can be checked in the video at the 25:08 timestamp.

After the transition to Google mobile-first indexing, the search engine will sometimes apply the Googlebot to desktop pages. But in general, a web resource crawling will be carried out by a mobile user-agent.

Мobile-first Indexing and Mobile-friendly – What is the Difference?

Мobile-first indexing and mobile-friendly are not the same. The mobile usability of a site is responsible for the correctness of content displaying on smartphones and other mobile devices. You can read another article for more detailed information about what mobile-friendly means. Let’s get back to mobile indexing.

In a video from January 2019, Müller said that even if a platform is not mobile-friendly, it will still be indexed for mobile search results. The question is into which position will it be placed.

This is why the results of the check by Google webmaster tools mobile-friendly won’t guarantee quick indexing and getting into the top 10.

This information can be heard at  41:12 in the video.

How do You Prepare a Site for Mobile-first Indexing?

The process of site indexing is slow, this is caused by the necessity to crawl each particular page separately. Besides, not all sites meet the requirements for the new algorithm. Although you cannot speed up the process, you can prepare for the transition.

So, if you have not received a notification from Google, you can check for yourself if the site is ready for indexing. This will help to avoid future problems. Follow the guide below based on the Google recommendations:

  1. If you have two versions of a site, mobile and desktop, they must have the same content. In a majority of cases, the desktop version was considered as the main one. Its content was of a higher quality than the mobile version. With the view of the new algorithm, it is more rational to make the content of both versions the same for desktops and mobile devices. Sites with adaptive design won’t be influenced by this.
  2. For both versions, it is better to use the identical semantic markup and mobile URL. Delete all data that is irrelevant to the content.
  3. The meta tags of mobile and desktop versions should be also the same. It is acceptable that meta title and description are shorter for the mobile versions, but they should contain the same keywords.
  4. When using the language markup rel=hreflang, the links should follow the analogic versions. So, it is not allowed that the mobile address links to the desktop version, and vice versa.
  5. OpenGraph and other markups for social media should be adjusted for both versions of the site. 
  6. Check the availability of Sitemap with the file robots.txt for mobile pages.
  7. When you set the utility App Indexing, verify both the desktop and mobile versions.
  8. If your mobile URL is located on the subdomain like, check the server storage capacity. It should be able to cope with a high load during crawling by the search bot. 

Adaptive design is not an all-inclusive solution. If the optimization for the Google search system requirements is absent, the site won’t reach the top-10 or higher positions. All the content should be correctly displayed on mobile devices, and the speed of the optimum load should be up to 3 seconds. There is no need to make any special adjustments.

How to See the Mobile Version of a Website on a Desktop

It is recommended to check how the mobile version of a site is displayed:

  1. Download and start the Chrome web browser and open the platform.
  2. After loading, press F12.
  3. The screen will be divided into two sections, on the left side, there is a desktop version and on the right side, there are codes.
  4. Press the button to choose the device, it is placed in the left upper corner of the section with the site codes. The mobile version will open. 

This will help you to evaluate the quality of the resource and improve it if necessary.

How to Check if the Site has been Indexed

After Google indexes the site, you will get an email notification with the subject “Мobile-first indexing enabled for your domain.”


If there is no email, it is possible to check the indexing with the help of the Google mobile site checker in the Search Console. To do so, you have to type the address of any of the site’s pages and check when the Google search robot has crawled and indexed it for the last time.

After receiving a notification, the activity of Googlebot will noticeably increase. Upon the termination of the crawling, the mobile version of your site will be displayed on the search results page. Platforms with adaptive design won’t experience any considerable changes. If a site only has a desktop version, then its position can worsen. After indexation, it is recommended to carry out a site audit, you will be able to find out how the algorithm has influenced the ranking.

All the aforementioned changes will influence old sites as well. Starting on  July 1, 2019. new resources have transferred to the mobile-first indexing by default, as is mentioned in the official Google resource.

Webmasters Google

What Criteria Should be Taken into Account When Developing a New Site

Google mobile-friendly ranking introduced changes to the development of new sites, it is now necessary to take into account the following criteria:

Give preference to concise textual content. Long articles with more than 4 thousand symbols will be less readable on a smartphone.

  1. It is better to decrease the number of categories and subcategories to a necessary minimum. By doing so, you will improve the site’s usability.
  2. When developing an adaptive design, all the elements of visualization should be convenient for touch-screen use.
  3. When developing a mobile version of a site, make it equal to the desktop one and follow all the main guidelines from Google described in the above section of the article.

How Mobile-first Indexing will Influence Sites’ Ranking

Now, in the sites’ ranking, the mobile has become the main version. However, in the case of its absence, the desktop version will be indexed. Meanwhile, it is not mentioned anywhere how this will influence the rating in the search results. Though it is recommended to optimize content for mobile devices, if this is not done, the ranking may be worse in comparison to that of mobile resources.

It is Bridget Randolph’s opinion, a digital marketing consultant at Moz, that the variation of the positions of the different versions of a site will be seen in SERP.

“You will probably see different results of ranking between the desktop and mobile versions. Therefore, it is necessary to track indices for every version separately. This is related to various factors, including behavioral.”

The different ranking results can appear as the result of problems with the usability and work of the site in general. For example, a mobile version has a higher loading speed, which is why its rating is higher. Or the users can find using the desktop version more convenient.

According to the forecasts, the rating for those sites that have content and metadata that are different in desktop and mobile versions will decrease, as well as for the resources with poor optimization for smartphones and similar devices. The platforms with adaptive design won’t be influenced by changes. The most important thing is to follow the recommendations of Google for usability, load speed, and navigation. A Google mobile page speed test can help check how quickly the content is loaded. There is no precise information on whether or not there is a difference in ranking of sites with adaptive design or with a separate mobile version.

According to specialists, the new algorithm will be able to completely replace the system of indexing. In MOZ, the theory has been mentioned that in the future, Google will rely less on the URL addresses in favor of a transition to API. In their blog, they refer to Cindy Krum from Mobile Moxie.

“Previously, SEO worked with one URL for every piece of content. This was related to the fact that the search system used addresses, their structure, and metadata. As it is impossible to present all the volumes of information, which are not formatted in HTML, in the browser, the changes will come. They are accessible only through API. And the search engine will use this data in mobile-first indexing.

After all the sites transition to mobile-first indexing, SEO will more often need to use API-services in their work. 

Aside from the changes mentioned above, the algorithm will influence the content as well. The indices of the voice search have grown considerably, this means that users expect to get responses that are the closest to the style of conversation. This implies the use of expressions that are shortened to a word, simple sentences, and slang.

There is also the tendency in the growth of personal requests with the use of pronouns. According to Google, similar requests are divided into three categories (with examples):

  1. Presence and solution of the problem  – “How can I repair a toaster?”
  2. Setting the target – “How can I lose 5 kilos by summer?”
  3. Request for the search of a location – “Where can I get lunch in New York?

For any type of mobile search request, it is possible to create pages of different types. For example, with different lengths of response, with infographics, maps, etc.

Mobile-first indexing is a predictable action for Google with the view of increasing smartphones’ traffic. If you haven’t yet received an email notification that the bot has completed scrawling, there are two ways to proceed. It is possible to check how your site works regardless of what kind of design it has, adaptive, or the separate mobile version. If everything is fine, it is worth waiting for an email, and from time to time check the results in the Search Console.

Pay attention to content. The optimization of the content for the Google mobile search engine will increase your chances to get to the top positions in SERP.

About author
Anna is a content manager and copywriter since 2013. In 2017, she started working as a copywriter and editor at a digital agency. In 2019, she began to cooperate with a SERM agency. The main responsibility is writing of the corporate blog. In 2020, she completed courses in SEO-optimizer and began cooperation with SeoQuake as a content manager.