What is mobile first indexing?

[albertocosta]

What is mobile first indexing?

[RH-Calvin]

It means that Google uses the mobile version of your webpage to index and rank in search engines.

[Raju]

Google is using the mobile version of a webpage to rank the specific content. With the latest Google algorithm update this is possible.

[vinu1997]

It means that Google uses the mobile version of your webpage to index and rank in search engines.
Historically, the index primarily used the desktop version of a page's content when evaluating the relevance of a page to a user's query.

[nick0201]

The mobile-first indexing was launch on 26 March 2018. The purpose behind this update that google will be focus mobile version of the website rather than desktop version to the rank website in search engine.