How to Optimize for the Mobile-first Index

Most websites have been ‘mobile friendly’ for quite some time now; however, Google is still pushing on with their effort to create a mobile-friendly web for all users, and this switch to a mobile-first index is their way of forcing websites to conform.

Google will be rolling the launch of the mobile-first index out slowly. In fact, they started towards the end of 2017, rolling out the index to websites that were deemed ‘ready’ enough for the change to have a minimal impact.

As 2018 rolls on though, Google will begin to roll out the mobile-first index across more and more sites, but this phased roll out will give webmasters time to get their websites in order.

What is the mobile-first index?

The mobile-first index is Google’s strategy to determine your rankings based on the indexing of your mobile website. At the moment, all rankings are taken from the desktop version of your website, even your mobile rankings.

The mobile-first index will take your mobile website first, and you potentially might see an increase in Smartphone Googlebot crawls to your site.

For most websites there won’t be an enormous shift. For anyone who has a responsive website, the content on desktop and mobile is usually exactly the same. If the content you choose not to show has strong SEO benefits on desktop, you are going to need to take a close look at this and work out how to bridge that content gap while still providing an excellent UX.

3 Key areas to focus on to optimize for the mobile-first index

1. Site Speed

Google’s primary objective with the mobile-first index is to construct a better UX on mobile devices. This makes a lot of sense given that mobile search has overtaken desktop search. With that in mind, one critical area they are trying to improve is the page load speed.
A fast loading website on mobile will usually provide a significantly better UX (assuming the content is relevant), so any improvements you can make to either your site or your mobile responsive website will help prepare for the mobile-first index.

Here are three ways you can speed up your site on mobile:

  • PWA – Progressive Web Apps (PWAs) are an alternative to moving to AMP. Their main selling points include:
  • Reliable – loads instantly
  • Fast – responds quickly to user interactions
  • Engaging – feels like a natural app on a device with an immersive UX
  • PWAMP(!) – a term first introduced by Google’s Gary Illyes at SMX Seattle, PWAMP is a combination of a PWA built on AMP HTML, JS and CSS. While PWAMP sites may not validate as AMP pages, they are lightning fast and provide all the benefits of a PWA as listed above. They could be the future and one to keep an eye on.
  • AMP – The Accelerated Mobile Pages (AMP) Project is an open source initiative to improve the mobile ecosystem. Thanks to the pared-down HTML that is used by AMP, it allows you to load your web pages much faster than regular HTML. Google also caches your content within their cache to speed up load time even more. All this results in a much faster, sleeker user experience and should, in turn, lead to improved visibility in the search results.

2. Content

The next critical area to focus on is the content itself. To rank your content from your mobile site, Google needs to be able to access it. That means you need to make sure the mobile version of your website has all the high-quality, valuable content that exists on your desktop website including images, videos, links, and copy. Make sure all the content is crawlable and indexable.

To find out if there are any differences between the content that Google sees on your desktop site and mobile site, you can use the awesome Screaming Frog tool to find out where those gaps appear. Simply crawl your site using the different user agents and then analyze these results. Moz recently published an awesome blog post on conducting parity audits that could just save your bacon.

3. Technical

The final aspect to consider is the technical elements of your mobile set-up. There are a number of areas to consider, and making sure that you are deploying the same technical elements on your mobile site as you are on desktop will be critical.

Here are a few areas to focus on:

Google Search Console Verification – if you currently only verify your desktop site in Google Search Console, you will need to ensure the mobile version of the site is also verified so you can get live, up to date information about crawling, indexing and any issues on your site.

XML Sitemap and robots.txt – make sure any links to your XML sitemap are accessible from the mobile version of your site. The same applies to the robots.txt file as there could be ramifications if this is not accessible and you have pages that you control using the disallow command or other key instructions.

Structured Data – if you are using structured data markup on your desktop site, you also need to make sure this is deployed on mobile too. URLs shown within structured data on mobile pages should be the mobile version of the URL.

Metadata – ensure that the key metadata elements (page titles and meta description) are equivalent on both versions of your pages. The reason Google recommends ‘equivalent’ rather than ‘identical’ is to potentially optimize your titles for the shorter real estate in the mobile SERPs. However, you do need to make sure you are including the same keywords in your page titles on mobile.

Social Tags – Open Graph Tags and Twitter cards (as well as other social metadata) should be included on the mobile as well as the desktop version of the site.


The mobile-first index is happening now, so it is time to get into action. Begin with audit of your desktop and mobile websites, highlight any potential problems then get to work on fixing them along with making those all-important website speed improvements and you will find that you will soon be set for the change.

Jamie FitzHenry is the founder of Grizzly, an SEO Agency based in Bristol, UK.