Mobile-First Indexing

Mobile-first indexing means Google predominantly uses the mobile version of a page's content for indexing and ranking, even for searches performed on desktop.

This has been Google's default for effectively all sites since 2023–2024. The practical implication: content, links, or structured data that exist on a desktop page but are hidden or removed on the mobile version are effectively invisible to Google, regardless of how complete the desktop experience looks. Responsive design (same HTML, CSS-driven layout changes) avoids this risk entirely compared to separate mobile (m-dot) site architectures, which is why nearly the entire web has moved away from separate mobile URLs.