Google predominantly uses the mobile version of a page for indexing and ranking. If something is missing or broken on mobile, it effectively does not exist for search.
What this means in practice
- Your mobile and desktop content must match (same text, headings, structured data)
- Anything hidden on mobile may be discounted
- Mobile speed and layout affect rankings and conversions
Common mobile problems
- Content missing on mobile that is present on desktop
- Structured data only on the desktop version
- Meta robots or canonical tags differing between versions
- Interstitials covering the content
- Tap targets too small or too close together
- Horizontal scrolling from fixed-width elements
Checklist
- Use a responsive layout
- Keep one URL for both, serving the same HTML
- Test on real devices and with the mobile-friendly test
- Ensure text is legible without zooming
- Make the primary action reachable with a thumb
Verify
After changes, check the page's canonical and structured data with the canonical checker, and run a quick content audit with the on-page tool.