Key takeaways
- Google indexes and ranks the mobile version of your pages, crawled with a smartphone crawler.
- Your mobile pages need the same content, titles, structured data and images as desktop.
- Responsive design is Google's recommended setup because it uses one URL and one HTML.
- Test on a real phone: speed, readability and how easy it is to call or buy.
Most of the sites I audit in my technical SEO work look fine on a laptop and have problems on a phone: menus that hide content, huge images, buttons too close together. Since Google ranks the mobile version, those problems matter more than the desktop design.
What is mobile-first indexing?
Mobile-first indexing means Google uses the mobile version of a page, crawled with its smartphone crawler, to index and rank it. If your mobile page has less content than your desktop page, Google works with the smaller version. Google strongly recommends having a mobile-friendly version, though it is not required to appear in results.
This is how Google describes it in its mobile-first indexing best practices.
What is the best mobile setup for SEO?
Responsive design: one URL and the same HTML for every device, with the layout adapting to the screen. Google recommends it because it is the easiest to implement and maintain. Separate mobile sites on another URL and dynamic serving can work, but they double the chances of the two versions drifting apart.
Mobile SEO checklist
- Same main content on mobile and desktop; tabs and accordions are fine if the content is there.
- Same titles, meta descriptions and structured data on both versions.
- Do not lazy-load main content that only appears after a tap or swipe.
- Images in good quality and supported formats, with the same alt text.
- Text readable without zooming and buttons easy to tap.
- Phone number and contact buttons one tap away.
- Pages that load and respond fast on a mid-range phone.
Each point comes from Google's mobile-first indexing guide or its image SEO best practices.
How does mobile speed affect SEO?
Speed on a phone is part of page experience, which Google measures with Core Web Vitals from real users: how fast the main content loads, how quickly the page responds to taps and how stable the layout is. Slow mobile pages also lose visitors before they read anything, which hurts leads even more than rankings.
See Google's Core Web Vitals page and web.dev's explanation of Interaction to Next Paint, the responsiveness metric. I go deeper in Core Web Vitals and INP.
How do you test your site on mobile?
Use your own phone on mobile data, not office wifi, and try the three things a customer would do: find a service, read the price or details and contact you. Then check Core Web Vitals in Search Console, which uses real-user data. Fix what blocks a customer first, then what slows them down.
Design decisions shape most of this, as I explain in why website design matters for SEO. New sites I build through my web design and development service are designed mobile-first. As an SEO consultant, I can test yours in a free diagnosis: book it here.
Frequently asked questions
Does Google still index desktop pages?
It indexes the mobile version for ranking. Keep both versions equivalent.
Is an app the same as a mobile site?
No. Google indexes web pages; an app is a separate product.
Are pop-ups bad on mobile?
Intrusive pop-ups that cover the content hurt the experience. Keep them small and easy to close.
Do I need AMP?
No. A fast responsive site is enough.
Can hidden accordion content rank?
Yes, if it is in the page and equivalent to desktop.
About the author
Juan José Giraldo is an SEO consultant in Medellín, Colombia, with 5+ years of experience. He works on technical and local SEO for 600+ US car dealerships at Reunion Marketing, an Inc. 5000 agency, and supervises the SEO of 18 US online stores with more than 3 million products at Prontomowers. Read more · LinkedIn.
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