What is mobile-first indexing?
Mobile-first indexing means Google indexes a page using the mobile version of its content, not the desktop one, even for a search happening on a desktop.
The word mobile in the name makes it sound like it only affects mobile search results, and that's the common misreading. It doesn't: it determines what goes into the index in the first place, so if content is missing, collapsed, or hidden behind a tap on the mobile layout, that content can be absent from what Google knows about the page at all, regardless of which device the eventual searcher is using.
The check worth running on any responsive site is whether the mobile and desktop versions contain the same text, not just the same visual layout. Content hidden in a mobile accordion still counts as present if it's in the HTML and only visually collapsed; content genuinely removed or truncated for the mobile viewport is content Google, and by extension anything built on Google's index, never sees.
Related
- IndexationIndexation is whether a search engine has stored your page and is willing to return it. Being crawled is not the same as being indexed, and being indexed is not the same as ranking.
- Core Web VitalsCore Web Vitals are Google's three metrics for real-world page experience: how fast content loads, how quickly the page responds to input, and how much the layout shifts while loading.
- Server-side renderingServer-side rendering means the HTML arrives complete from the server. It matters because most AI crawlers do not execute JavaScript, so content injected in the browser is invisible to them.
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