Viewport meta tag
The `<meta name="viewport">` declaration that tells mobile browsers how to size and scale a page to the device screen.
Technical
Mobile-first indexing
Google's practice of crawling, indexing and ranking based on the mobile version of a page; completed for all sites by mid-2024.
In full
Since the rollout finished, content, structured data, links, images and metadata that exist only on a desktop version are effectively invisible to Google. Separate m-dot sites and adaptive templates are the highest-risk configurations because content parity is easy to lose. Responsive design with identical content and markup across breakpoints is the recommended configuration; Google also retired the standalone Mobile-Friendly Test and mobile usability report as the transition completed.
Example
A site hides its FAQ block below 768 px with `display:none` and loses the associated long-tail rankings once mobile-first indexing applies.
Related terms
Responsive web design
Serving the same HTML at one URL and adapting layout with CSS media queries and flexible units, Google's recommended mobile configuration.
Googlebot
Google's main web crawler, which fetches pages for Google Search using two user agents: Googlebot Smartphone and Googlebot Desktop.
Page experience
Google's umbrella term for signals about how users perceive interacting with a page, including Core Web Vitals, HTTPS and absence of…
Structured data
Machine-readable annotations on a page, usually Schema.org vocabulary in JSON-LD, that describe entities and make pages eligible for rich…