It’s been a long time coming, but Google is officially changing its search index in order to get serious about mobile. Enter the new kid on the block, the mobile-first index.

There have been plenty of warning signs, including the ‘Mobilegeddon’ update back in April 2015, and earlier this month Google announced that their algorithms will primarily use the mobile version of a site’s content to rank pages.

This will turn their current indexing practice on its head, but what does it all mean for your brand’s website, and what do you need to know?

In this post you’ll be learning the crux of what mobile-first index means for you and your business, and how this update will affect the future of search.

Let’s dive right in…

So, what’s different?

Google currently crawls the desktop versions of web pages and indexes them in both mobile and desktop search results. The “mobile-friendliness” of a page helps to boost rankings in the mobile search results, but overall rankings are mainly based on the desktop version.

This is an issue for Google though, as some websites serve different or shortened content on mobile devices, and as sites are ranked based on the desktop version, mobile users may not actually see the information they are expecting to find when clicking through to a site. And with mobile and tablet usage now ahead of desktop, the search giant wants to address this flaw:

“Our ranking systems still typically look at the desktop version of a page’s content to evaluate its relevance to the user. This can cause issues when the mobile page has less content than the desktop page because our algorithms are not evaluating the actual page that is seen by a mobile searcher.” – Google, November 2016

It was initially thought that there would be separate indexes for mobile and desktop rankings, but Google has stated that it “will continue to be a single index of websites and apps” and mobile pages will be the primary focus.

In short, optimise your mobile site or performance overall could suffer.

Who will be affected?

The changes are being tested and rolled out on a small scale over the next few months, and Google will only ramp things up when they are confident that it will actually improve user experience.

Both Gary Illyes and Paul Haahr from Google have revealed that they want there to be minimal change in rankings with this update, but it is too soon to say.

The good news is if you have a responsive website or dynamic serving site, where content and mark-up is equivalent across mobile and desktop, you shouldn’t have to change much at all.

Unfortunately, for those with a separate mobile site or URLs, you will need to consider the impact this may have and take action promptly.

If you don’t actually have a mobile site, Google has said that they will “continue to index your desktop site just fine, even if we’re using a mobile user agent to view your site”. You should only see this as a compromise though as Google has been very clear on the importance of providing a good mobile experience and where the future of search is heading.

This doesn’t mean you need to rush off and get a brand new website, but a responsive site should be top of your priority list. Google put it best in their announcement:

“If you are building a mobile version of your site, keep in mind that a functional desktop-oriented site can be better than a broken or incomplete mobile version of the site. It’s better for you to build up your mobile site and launch it when ready.”

What you need to know


The first thing you need to consider, even with a responsive website, is the level of content available on your desktop pages compared to mobile. As your site will be ranked based on the mobile version with potentially less or hidden content, this could impact your search visibility, particularly for long-tail queries.

You may be thinking that more text on your mobile site could impact experience though, as users don’t want to scroll through lots of text on a small screen. The good news is that Google have said that with the mobile-first index, content hidden in tabs, accordions, expandable boxes and other methods should be given full weight, while it’s usually devalued for desktop pages.


Similar concerns to the above have been raised about links, as mobile content tends to include fewer links than desktop, whether they are internal or external.

As content and links are two of the main factors for Google’s search algorithms, surely this will impact rankings?

Google has said they are still testing, so it isn’t 100% clear. Gary Illyes said, “I don’t want to say anything definite about links yet. It’s too early for that because things are very much in motion.”

Structured Data

The advice provided by Google so far has included some useful points about structured data. This is data that’s highly organised and predictable thanks to a markup format like, allowing search engines to easily understand and display the information in creative ways, such as Rich Snippets and Knowledge Graph cards.

Make sure that your structured markup is equivalent for both the desktop and mobile versions of your pages, otherwise you could lose any featured or rich snippets that your site currently occupies in the search engine results pages (SERPs).

You can do this by typing in both versions of a URL into the Structured Data Testing Tool and comparing the output.

Search Console

Another tool that you need to use is ‘Fetch as Google’ in Search Console. If you set the user-agent to mobile:smartphone and click ‘Fetch and Render’, this will allow you to see what Google can see when crawling and indexing your website or mobile site, and help you to start identifying any content that is missing.


Also, the robots.txt testing tool can help to check that the mobile version of your site is accessible to Googlebot. If you have a separate mobile version of your site on a different domain or subdomain, such as m. URLs, make sure to verify this as its own property in Search Console and then use the tool.

Other Technical

There are a number of other technical factors that will need to be considered to ensure your mobile site is fully optimised ahead of desktop, such as page speed, title tags and H1s, and I imagine full guidance on this will be provided by Google as things progress.

Google has said that canonical tags, which help to deal with duplicate content, do not need to change though, as they will continue to use these links as guides to serve the appropriate results to a user searching on desktop or mobile.


Finally, if you have read our guide to Accelerated Mobile Pages (AMP) you will know all about this recent Google-backed project to improve mobile user experience and loading speeds across the web.

According to the SEM Post, the mobile-first index won’t change anything for the existing AMP set-up, but it’s expected that the adoption of AMP will be a key focus for Google next year and beyond, so watch this space.

I do expect Google to change their stance on a number of things, especially as the mobile-first index is still being tested and called an “experiment”. But the one thing that is clear, is that brands and businesses who don’t prioritise mobile and have a dedicated mobile SEO strategy today, will be left behind in tomorrow’s world of search.

If you have any questions about the mobile-first index, please feel free to get in touch on Twitter, @Silverbean.