With mobile-first indexing, a mobile-optimized website becomes a must-have.
A new era is dawning – in search engine optimisation. The name for this change is mobile-first indexing. And what does it stand for? ONELINE explains and clarifies the special features of mobile SEO. After all, this type of search engine optimisation is becoming increasingly popular – for one simple reason: mobile use of the internet has increased significantly in recent years. In 2023, 64.4% of all search queries worldwide were carried out via mobile devices. Figures provide impressive facts that prove the end of the desktop era. This can be compared to the disappearance of the digital camera. High-quality smartphones have replaced them in many private households. In terms of search engine optimisation, Google has reacted in good time. The company has adapted its technology to this change. Mobile-first indexing takes centre stage.
What does mobile-first indexing stand for?
With mobile-first indexing, the mobile version of a website is used for indexing and ranking in the search results.
Google is almost synonymous with the term “search engine”. Competitors are unable to knock Google off its monopoly throne. This is why ONELINE is focussing on Google in this article. After the first click on the selected hit of a search, users see the content that the search results show them. However, this is only possible if the search engine’s crawlers have the same perspective as the user. Googlebot is another name for the search engine crawlers. Because the majority of internet users now use their mobile phones for search queries, a change is taking place.
Google started a mobile index turnaround in 2016. After almost 7 years, the switch to mobile-first indexing is now complete. Now practically all websites are crawled with the Googlebot for mobile pages, which means that the mobile view counts for indexing. A few websites could not be converted, for example because they redirect from the mobile pages to the homepage or have errors on mobile pages. Minor adjustments were also made in the Google Search Console. As crawling is now mainly carried out by Googlebot Mobile, the information on the crawler used is no longer displayed within the Google Search Console. Users who want to find out which crawlers are visiting their website can view the crawling statistics in the Google Search Console.
What results from mobile-first indexing?
Google views websites in the same way as a smartphone user. According to the service company, in September 2020 around 70 per cent of all websites were automatically converted to mobile SEO. The search engine owes this task to the clever Googlebot. After an automated check, it determined that the majority of websites fulfil the necessary conditions for mobile-first indexing. On the other hand, a third of current websites are not yet ready for mobile SEO. Since October 2023, all but a few websites have been converted to the mobile-first index.
ONELINE explains how website operators should proceed in order to meet the requirements of mobile-first indexing. The Google Search Console used to be the first, indispensable point of contact. It provided information on whether a website was using mobile-first indexing. Since the changeover was completed, the Google Search Console no longer provides information about the crawler. Instead, you can use the PageSpeed Insights tool to gain valuable insights into the performance of your mobile website and receive recommendations for possible optimisations. Google also supports website operators. It provides them with a useful document. It is called “Best Practices“. The following aspects play the main role here:
In terms of crawlability, the Googlebot is by no means obliged to crawl a mobile website version completely. Website operators check their Robots.txt and Robots meta tags for this purpose. They also enable the search engine to load all website content effortlessly. This includes images, JavaScript files and CSS.
There is another important message that responsible web designers should never neglect. This indicates why the website content of a conventional presentation should be the same as that of a mobile version. Different page displays cause confusion for website visitors.
Why Responsive Design acts as the ideal solution for Mobile SEO.
Some website operators still make a crucial mistake: they use different URLs for their mobile and desktop site versions. However, experts advise against this method because it causes inconsistencies. Not even Google is able to equalise such website configurations. This is why informed web designers are switching to responsive design. This method is an excellent technique. With the help of CSS3 media queries and HTML5, it guarantees a congruent presentation of website content. Responsive design is characterised by a decisive advantage: The website design scores with its flexibility and adaptability. In addition, the layout impresses with its universal user-friendliness – regardless of whether it is displayed on a computer desktop, smartphone or tablet. Website visitors benefit from short loading times. Readers also process the content faster and better. Both aspects act as important ranking factors.
The three Fs also serve as the best possible explanation for responsive design, as it stands for “form follows function”. In other words: design, function and content adapt to the screen resolution of the end device. The literal translation for responsive design is responsive web design. This design adapts to the circumstances of the website visitor – and not the other way round.

Advantages of Mobile SEO
Mobile SEO impresses with an underestimated feature: The maintenance effort of the editorial website content is lower. Whereas a strict separation of the desktop and the mobile website version is associated with a high maintenance effort. However, another reason exists why mobile-first indexing is gaining acceptance in practice: 100 percent mobile-first indexing is due in March 2021. This raises the question of how website designers should proceed to keep up with the demands of SEO Mobile.
Helpful tips for a successful transition to Mobile SEO
The SEO agency ONELINE recommends the following steps to perform successful mobile-first indexing. In the first place, the mobile page version should have numerous technical elements. The exciting question is, “How can webmasters check this aspect?” – Simple. They set up a free Ahrefs Tools account for this purpose. Then, they first crawl their website using the “Site Audit” option. The default setting crawls the site with the help of a desktop-user agent. This allows webmasters to see the website exactly as it appears on a desktop. However, all it takes is a click on the tab called “Crawl Settings.” There, website designers make a simple change by switching to the “Mobile” option. ONELINE recommends crawling the desktop variant first before making the change. Thanks to this procedure, the integrated comparison function clarifies whether problems still exist. These can occur on a mobile device. JavaScript, CSS, and image files should be crawlable on all pages.
Which detail decides whether mobile-first indexing is crowned with success? – Load time. Long loading times are devastating: for the website visitor and the website operator alike. That is why Google measures the loading time. The mobile page version serves as the basis. For successful mobile SEO, webmasters check this indispensable detail in their Google Search Console under the category: Extension – Core Web Vitals – Mobile. In addition, a visual inspection is required. This includes checking the existing interstitials. These are pages that require website visitors to confirm their age or allow advertisements. These should take up little space for successful mobile-first indexing.
What is the difference between a mobile and a desktop website?
The differences lie in the display options. After all, the screens on mobile devices are much smaller than desktop screens. Sidebars as well as extensive menus do not exist on mobile websites. Therefore, there is no obligation for an identical display of a mobile and a desktop version. But the most important content of the website must not be missing on the mobile version in any case. Once there existed significant differences in the display between the two versions. The mobile website did not display all the content. Thanks to mobile-first indexing, this has changed in favor of users. The search engine presents all content. In comparison: Google withheld hidden content from website visitors to optimize their user experience.
Mobile SEO has successfully displaced “normal” SEO.
Corrected, the statement reads: users have replaced traditional search engine optimization with mobile-first indexing thanks to their website usage. Once upon a time, to stay in the market, businesses and nonprofits had to perform successful SEO. An undetectable website was comparable to a non-existent business. Now, in the age of the mobile era, mobile SEO dominates. Those who deliberately ignore or unintentionally sleep through this change lose the battle against the competition. Even more: they lose customers. Regular customers and new customers. That’s why mobile-first indexing should be a top priority for all website operators. Because a flawless online presence is now as important to entrepreneurs as the air they breathe.
Google does not make such changes to annoy website designers. Instead, the company’s goal is to improve the way everyone uses the Internet. The push for SSL encryption provides proof of this fact. Everyone benefits equally from innovations. Thus, the switch to Mobile SEO is inevitable and acts as a boon for everyone.
The future of mobile SEO
Page experience in focus
The user experience on mobile devices is moving to the centre of mobile SEO. Google attaches great importance to factors such as loading speed, readability and user-friendliness. Websites that offer an excellent page experience are prioritised in the search results.
Voice search on the rise
Voice search is rapidly gaining in importance, especially on mobile devices. Websites should be optimised for voice search by integrating long-tail keywords and questions that users typically ask.
Progressive web apps (PWAs) for seamless use
PWAs combine the advantages of websites and apps and offer a fast, smooth user experience on mobile devices. By implementing PWAs, mobile SEO performance and user engagement can be increased.
Structured data for better understanding
Structured data helps Google to interpret and categorise the content of a website. This can improve visibility in search results and lead to a more targeted approach to users.
Mobile analytics: data-supported optimisation
Mobile analytics tools can be used to analyse user behaviour on mobile devices in detail. This valuable data can be used to optimise the website and the mobile SEO strategy.
Artificial intelligence (AI) as a game changer
AI tools are revolutionising the field of SEO. They support content optimisation, keyword research and backlink strategy, enabling more efficient and effective search engine optimisation.
The future of mobile SEO is characterised by a strong focus on user experience, the integration of new technologies such as voice search and PWAs and the use of data-driven optimisation approaches and AI tools. Companies that actively shape these trends will be successful in the mobile search landscape of tomorrow.
Updated: March 2024