As of March next year, Google plan to enable mobile-first indexing for all sites. Most existing websites and all new websites are already indexed in this way, but Google will switch all their indexing to mobile-first in a few months. What does this mean for retailers? We highlight how retailers can better prepare their sites to be search engine optimised for mobile-first indexing. 

The main points to consider are: 

  • Ensuring Google’s bots can see your content 
  • Having the same primary content on both desktop and mobile 
  • Following best practices for images and videos 

Ensuring Google Sees Your Content in Mobile-First Indexing 

In mobile-first indexing, Google will only get your site’s information from the mobile version. This means that Googlebot will need to be able to see the full content and all resources there. Addressing the three points below will help ensure Google will continue to see all the content you have worked to accumulate. 

Robots Meta Tags 

You should use the same robots meta tags on the mobile version as those on the desktop version. If you use a different tag on the mobile version (such as noindex or nofollow), Google may fail to index or follow links on your page with mobile-first indexing. 


Lazy-loading is more common on mobile than on desktop, especially for loading images and videos. We recommend following Google’s lazy-loading best practicesAvoid lazy-loading your primary content based on user interactions (like swiping, clicking, or typing), because Googlebot won’t trigger these user interactions. 

For example, if your page has 10 primary images on the desktop version, and the mobile version only has 2 of them, with the other 8 images loaded only when the user clicks, Googlebot won’t see the 8 images. This means they won’t be indexed or shown in Google Images.  

Be Careful When Blocking 

Some resources have different URLs on the mobile version from those on desktop and they could be served on different hosts. To get Google to crawl your URLs, make sure you’re not disallowing the crawling of them with your robots.txt file. 

Blocking the URLs of .css files will prevent Googlebot from rendering your pages correctly, which can harm the ranking of your pages in Search. Likewise, blocking the URLs of images will stop them from appearing in Google image searches. 


Primary Content Consistency Across Desktop & Mobile 

Primary content is the content you want to rank with. Put simply, it is the reason users go to your site. You should consider updating your mobile version to hold primary content, especially if your mobile version holds less content than your desktop version. 

After March, only the content shown on the mobile version will be used for indexing and ranking. This means your site may lose some traffic (as Google won’t be able to get the full information) if your mobile version does not have your primary content. 

Meaningful Headings on Mobile Version

It is important to always use the same meaningful headings on your mobile version as on the desktop version. Missing meaningful headings may negatively affect your page’s visibility, as Google won’t be able to understand the page as easily. 

For example, if your desktop version has the following tag for the heading of the page: 

<h1>Photos of cute puppies on a blanket</h1> 

Your mobile version should also use the same heading tag with the same words for it, rather than using headings like: 

<h1>Photos</h1> (not clear and meaningful) 

<div>Photos of cute puppies on a blanket</div> (not using a heading tag) 


Best Image & Video Practice for Mobile-First Indexing 

To ensure your mobile version follows image best practices and video best practices, check the following areas. 

Image Quality

Images that are too small or have a low resolution on the mobile version are less likely to be selected for Google Images and could damage SEO efforts. 

For example, if your page has 10 images on the desktop version, and they are normal, good quality images. On the mobile version, bad practice would be to use very small thumbnails for these images to make them all fit in the smaller screen. These thumbnails may be considered poor quality by Google because they are small and low res. 

Alt Attributes for Images

As with meaningful headings previously discussed, alt attributes need the same attention and will affect how your images are shown in Google Images. 

Here is an example of good alt attribute practice: 

<img src=”dogs.jpg” alt=”A photo of cute puppies on a blanket”> (meaningful alt text) 

And here are two examples of bad alt attribute practice:  

<img src=”dogs.jpg” alt> (empty alt text) 

<img src=”dogs.jpg” alt=”Photo”> (alt text not meaningful) 

Image URLs

If your site uses different image URLs for the desktop and mobile version, you may see temporary fall in traffic from Google Images while your site transitions to mobile-first indexing. This is because the image URLs on the mobile version are new to the Google indexing system, and it takes time for new URLs to be understood. To minimise this temporary traffic loss, review whether you can retain the image URLs used by desktop.  

Video and Image Placement

On the mobile version of your pages, you should position videos and images in an easytofind location. Videos or images not placed well could affect user experience on mobile devices, making it possible that Google would not give them as much visibility as those in a good position. 


For more information on the best practices to put in place for mobile-first indexing SEO, see Google’s developer guide for mobile-first indexing.