PMG Digital Made for Humans

The Google Mobile-First Index Survival Kit

6 MINUTE READ | March 28, 2018

The Google Mobile-First Index Survival Kit

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Kara Eccleston

Kara Eccleston has written this article. More details coming soon.

This week, Google announced that it will be taking a mobile-first approach to building a single search index. This means that eventually, Google’s algorithms will primarily use the mobile version of a site’s content to rank pages from that site. And what THAT means is that if your site isn’t optimized for mobile, both your desktop and mobile rankings will suffer.

Historically, the index primarily used the desktop version of a page’s content when evaluating the relevance of a page to a user’s query. Since the majority of users now access Google via a mobile device, the index will primarily use the mobile version of a page’s content going forward. We aren’t creating a separate mobile-first index. We continue to use only one index.

But armed with the right tools, you can survive this mobile apocalypse. Here’s what you’ll need:

Make sure your mobile site is verified in Google Search Console so that you can monitor how Google is crawling and indexing your site. Use the Fetch As Google feature to see if Google Smartphone (select Mobile: Smartphone in the drop-down menu) can crawl or render your site (this can only be used on a page-by-page basis).

fetch as google

Using just fetch will only check the HTTP response and will not run any page resources (such as scripts, CSS, images, etc.). If you want to see the visual differences between how Googlebot sees your page and how a user sees your page, use fetch and render. This will request and run the resources on the specified page.

fetch as google

If you receive a partially complete status, some of your resources are blocked. Blocked resources can be problematic because they affect Google’s understanding of the page and thus affect your rankings.

blocked resources

If the severity of a blocked resource is low, this indicates that the missing resource has little effect on Google’s ability to render the page.

Once you unblock these resources, you can request that Google re-crawls your page using the Submit to index function. Can also check blocked resources by going to Google Index > Blocked Resources.

To get a holistic view of your site’s mobile usability, search traffic > mobile usability will tell you how many pages overall have mobile issues, what those issues are, and which pages contain those issues.

Research has shown that any delay longer than a second will cause the user to interrupt their flow of thought, creating a poor user experience. Admittedly not the most powerful tool you can use for analyzing page speed, Google’s PageSpeed Insights is a quick way to measure your site’s mobile and desktop performance.

PageSpeed Insights measures how the page can improve time to full page load and above-the-fold load. However, the absolute performance of the page will still be dependent upon a user’s network connection. Each suggestion is rated with a priority indicator to indicate its importance:




red exclamation point

Fixing this would have a measurable impact on page performance.

yellow exclamation point

Consider fixing this if it is not a lot of work.

green check mark

No significant issues found. Good job!

If you need a more in-depth page speed analysis, head on over to WebPageTest. From there, you will have more control over device, network, and testing location. You will also receive a summary of your page speed metrics (such as time to the first byte, document load time, the start render time), plus a waterfall chart so that you can pinpoint which resources are hindering page load.

mobile waterfall chart

One of the best features is the ability to compare two or more tests. For example, you may choose to compare your mobile site to your desktop site, your mobile site to your competitor’s mobile site, a 4G connection versus LTE, iPhone versus Samsung Galaxy, or your various page templates.

Google’s initiative for the mobile-first index revolves around improving the user experience for mobile searchers. When a site is not mobile-friendly, users struggle by having to pinch and zoom in order to read the content. This frustrating experience leads to site abandonment. To encourage better UX, Google rewards mobile-friendly sites with a ranking boost (at the page-level) because they are readable and immediately usable.

To take advantage of this ranking boost, check your pages the Mobile-Friendly Test.

Google uses the following criteria to determine mobile-friendliness,

  • Blocked JavaScript, CSS, and Image Files

  • Unplayable content

  • Faulty redirects

  • Mobile-Only 404s

  • Irrelevant cross-links

  • Slow load time

  • Viewports not set correctly

  • Small font size

  • Touch elements that are too close

Google encourages webmasters to check their sites for schema markup using the Structured Data Testing Tool. If you have a separate mobile site, you’ll want to compare the structured data on the desktop version of the site and mobile version of the site to see if they are equivalent. You can either fetch the mobile or desktop URL or paste a code snippet into a text field.

Google will render the client-side source code and display the detected schema items and their type.

test structured data

Clicking on the item will display the properties of that Schema type and their values.


If there are any errors or warnings in your markup, Google will display those as well. Errors will invalidate your markup and occur when a required field is missing or invalid. You can click on the row with the error and the tool will highlight its location in the DOM.

The tool will also display warnings. Warnings will not invalidate the markup but are typically schema properties Google recommends for that schema type. You can use the text editor to make changes to your markup and re-test it.


You can get a site-wide structured data report in Google Search Console. Go to Search Appearance > Structured Data and click download beneath the graph. 

structured data report

If your mobile site is separate from your desktop page or if you use AMP, you’ll want to use Screaming Frog SEO Spider to make sure your site has correctly implemented canonical and rel=”alternate” tags (use the XPath expression //*[@rel=”alternate”] in the custom extraction feature).  

You can also do a crawl of your site to check for any pages or resources blocked by robots.txt (go to user-agent configuration to switch between Googlebot and Googlebot for Smartphones). Lastly, you can export an XML sitemap after you complete a site crawl (non-200 URLs will automatically be discarded from the sitemap).

Screaming Frog has a log analyzer as well (this is a separate tool). Upload your server logs to analyze search bot activity by identifying which URLs are being crawled at what frequency. This would be a great tool to see which pages are getting the most attention from Googlebot for Smartphones or to find discrepancies in your analytics data.

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Hopefully, these tools will help you conquer the impending doom. May the fittest sites survive!

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