What is Mobile-first indexing?

Google's policy of using the mobile version of a site as the primary basis for ranking, meaning sites can rank differently on desktop versus mobile.

From How to Target Multiple Cities Without Hurting Your SEO by Loren Baker #500

Google's approach of crawling and indexing pages using a smartphone agent rather than a desktop agent, meaning the mobile version of a site determines search rankings.

From Mobile-First Indexing, Best Practices with Chris Burres and Matthew Bertram #437

Google's approach of primarily using the mobile version of a website for crawling and ranking, making mobile design a top priority for SEO.

From SEO For Web Designers : What you should know by Pawan Sahu #441

A Google approach where the mobile version of a website is used as the primary basis for indexing and ranking, flagged in the episode as something site owners should prepare for.

From How to Build Your Brand Online by Tom Ward #438

Google indexes the mobile version of a website first, meaning an incomplete or content-stripped mobile site can negatively impact overall search rankings.

From 4 Most Important Ranking Factors According to SEO Industry Studies by Aleh Barysevich #383

Google's practice of using the mobile version of a website as the primary version for indexing and ranking, meaning mobile optimization directly affects search rankings.

From Technical SEO: why it matters and seven tweaks to give you an edge by John Stevens #424