Google has been rolling out mobile-first indexing, and it represents a fundamental shift in how search works. Previously, Google's crawlers would look at the desktop version of your site to determine rankings. Now, the mobile version comes first.

What changed

With mobile-first indexing, Google predominantly uses the mobile version of your content for indexing and ranking. This doesn't mean desktop is ignored — it means mobile is the primary version Google looks at.

This makes sense when you consider that the majority of Google searches now happen on mobile devices. Google wants to index and rank based on what most users actually see.

What to check

First, make sure your site is responsive. If you're serving a completely different site to mobile users (an m.dot subdomain, for example), ensure it has the same content as your desktop version. Any content that's hidden on mobile — collapsed accordions, tabbed sections, or content behind 'read more' links — should still be crawlable.

Check that your structured data, meta tags, and alt text are present on the mobile version, not just the desktop version. If your mobile site is a stripped-down version of desktop, you could be losing SEO signals.

Also review your internal linking on mobile. Some mobile designs simplify navigation in ways that remove important internal links, which can affect how Google discovers and values your pages.

Testing your mobile site

Google provides two key tools for checking your mobile readiness. The Mobile-Friendly Test tells you whether a specific page meets Google's mobile usability standards. PageSpeed Insights shows you how fast your page loads on mobile and flags specific issues to fix.

Both tools are free and give you actionable recommendations. Run your key landing pages through them and address any issues flagged.

Mobile-first indexing isn't coming — it's here. If your site isn't optimised for mobile, it's now directly affecting your search rankings, not just your user experience.