Google's practice of using the mobile version of a page as the primary basis for indexing and ranking.
ID
SS-DF-038
Confidence
High · 89
Evidence
Strong
Updated
2026-07-08
Definition
Google's practice of using the mobile version of a page as the primary basis for indexing and ranking.
Mobile-first indexing means Google predominantly crawls, indexes and ranks the mobile version of a site's content rather than the desktop version. It became the default for all sites, so any content, structured data or metadata missing from the mobile experience effectively does not count. Sites must ensure their mobile pages contain the same important content and markup as desktop, typically through responsive design.