Mobile-First Indexing


As mobile devices become the primary way users access the internet, having a mobile-friendly website is no longer just a recommendation – it’s imperative for success. This comprehensive guide will provide critical information on mobile site development and mobile-first indexing, two essential strategies for search engine optimisation (SEO) in today’s digital landscape.

Understanding Mobile-First Indexing

Mobile-first indexing refers to search engines, particularly Google, using the mobile version of a website as the primary version for indexing and ranking pages in search results. Here are some key facts about mobile-first indexing:

  • Google switched to mobile-first indexing in 2018 as mobile usage continued to dominate web traffic.
  • Pages are still indexed by Googlebot, but the crawler will view the mobile version first when indexing and ranking pages.
  • Websites without a mobile version will be at a disadvantage, with Google often displaying the desktop version on mobile SERPs.
  • Dynamic serving is recommended, where users are automatically served the appropriate version of pages based on their device.
  • Mobile usability and speed are now weighted even more heavily by Google’s algorithms.

Best Practices for Mobile Site Development

When developing a mobile website or optimising an existing desktop site for mobile, here are some critical best practices:

  • Responsive web design: The site resizes fluidly based on the user’s device and screen size. This is achieved through CSS media queries and a flexible grid layout.
  • Fast load speeds: Optimise images, minify code, and leverage browser caching to enable quick page loads. Accelerated Mobile Pages (AMP) can also improve speed.
  • Easy navigation: Use a simple, intuitive IA with large touch-friendly buttons. Avoid nested navigation and keep menu levels to a minimum.
  • Readable typography: Content should be legible without pinching or zooming. Font sizes of at least 16px are recommended. Line-length should be 55-75 characters.
  • Minimal horizontal scrolling: No horizontal scrolling should be required to read content. Use responsive frameworks to prevent content spilling outside screen width.
  • Tap targets: Links and buttons should be large enough to tap easily, generally 48px x 48px minimum.
  • Eliminate pop-ups and interstitials: These often cause frustration on mobile and negatively impact conversions.
  • Mobile-friendly forms: Ensure forms are easy to fill out on a small screen with large input fields and submit buttons.
  • SSL enabled: Switch to HTTPS protocol for secure data transmission and better SEO. Free SSL certificates are available.
  • Accelerated Mobile Pages: Consider implementing AMP versions of key pages to boost page speed and exposure in the mobile SERPs.
  • App linking: Enable deep linking between your mobile website and app to allow easy navigation between the two.

Mobile Usability Testing

Continuously test your mobile website on real devices to identify usability issues. Involve real users early on and run usability studies on prototypes to uncover flaws before launch. Monitor analytics to identify points of failure and drop-off.

What are some common usability issues to look out for when testing a mobile website?

Here are some of the most common mobile usability issues to look for when testing a website:

  • Small text size – Content should be readable without zooming in. At least 16px font size is recommended.
  • Links and buttons too small – Tap targets should be large enough, around 48px x 48px minimum.
  • Content wider than screen – Avoid horizontal scrolling. Use responsive design to prevent content spilling outside screen width.
  • Difficulty typing into form fields – Make sure form inputs are large enough for fingertips and display keyboard correctly.
  • Hidden navigation menu – Hamburger menus can be confusing. Make sure menu is clearly visible.
  • Page slowdowns and long load times – Optimize images, minify code, and enable caching to improve speed.
  • Pop-ups and interstitials – These often frustrate users on mobile. Avoid if possible.
  • Broken functionality – Links, buttons, menus should all function properly.
  • Difficulty finding key pages – Use simple, intuitive navigation menus and site architecture.
  • Inconsistent design – Maintain consistency across device orientations and platforms.
  • Small buttons and links – Ensure tap targets have enough padding around them.
  • Unresponsive design – Site should resize fluidly on all devices. Test across multiple screen sizes.
  • Non-mobile friendly forms – Simplify forms, enlarge fields for fingertips, test submit button.
  • Lack of prominent calls-to-action – Ensure CTAs stand out and lead users to key pages.

Here are some recommended tools for testing mobile website usability:

  • Google Mobile-Friendly Test – Tests if pages are mobile-friendly and provides fixes.
  • Google PageSpeed Insights – Checks page speed and performance on mobile.
  • WebPagetest – Allows testing on real devices and examines page load speed.
  • BrowserStack – Enables cross-browser and cross-device testing across thousands of real mobile devices.
  • Hotjar – Creates heatmaps, recordings, and polls to observe mobile visitors.
  • Google Analytics – Provides data on site usage patterns and conversions on mobile.
  • Search Console – Google tool to see how site appears in mobile SERPs.

The most insightful testing though combines quantitative data with qualitative feedback from real users. Focus groups, moderated sessions, and surveys can also provide valuable perspective on the mobile experience.


As Google’s algorithms shift to favour mobile-friendly websites, having an optimised mobile presence is imperative for ranking well and providing users with a seamless experience. By leveraging responsive design, optimising for speed and usability, and enabling mobile-first indexing, businesses can future-proof their website and drive more organic search traffic.

This guide provides a starting point for developing an effective mobile SEO strategy. Be sure to regularly research updates in Google’s mobile algorithms and refine approaches accordingly. With mobile usage only increasing, search visibility on mobile is key to online success.

About the Author: Michael Masa

Why should you listen to me? With a rich background in marketing and a passion for sharing knowledge, I’ve dedicated the last 9 years of my life to the field. I’ve worked as a marketer and have been instrumental in crafting the marketing strategy for one of Europe’s leading insurance companies, BAVARIA AG.

Prior to my current role, I spent 12 years as a Sales Manager, leading a team of 12 dynamic individuals and implementing the latest sales techniques to drive success. This experience allowed me to refine my leadership skills and gain a deep understanding of the sales industry.

Now, I’m at the helm of Dealers League, a marketing agency that not only grows and manages websites for businesses but also focuses on the importance of effective marketing strategies. Recognizing the need for continuous learning in this fast-paced industry, we offer courses on the latest marketing techniques.

My varied experience in sales and marketing provides me with a unique viewpoint on how these two crucial areas intersect. I look forward to sharing my knowledge and insights with you through this blog.

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