Glossary · Content & Optimization
Mobile-First Indexing
The practice of using the mobile version of a webpage, rather than the desktop version, as the primary basis for crawling and indexing.
Why the distinction exists
Sites that serve stripped-down or differently structured mobile pages risk having a crawler index the reduced mobile version, meaning content only present on desktop may not be considered at all.
Practical implication
Any content meant to influence how a page is understood — headings, structured data, key facts — needs to be present on the mobile version of the page, not just the desktop version, to be reliably captured.
See more terms in the full glossary, or read the AI Visibility 101 guide for the full picture.