Mobile-first indexing
Mobile-first indexing means that Google uses the mobile version of your content for indexing and ranking, fetched with the smartphone crawler. What is missing from the mobile page cannot count for search, even if it is visible on desktop.
Where things stand
Google made the switch over several years, starting in 2016. Google announced the final step in June 2024: sites that were still being fetched with the desktop crawler moved to the mobile Googlebot after July 5, 2024. Since then Google fetches all websites for search with the smartphone crawler. Websites whose content is entirely inaccessible on mobile can no longer be indexed. The desktop Googlebot still shows up in server logs for other purposes, such as product listings.
There is still a single index. All that changed is which version Google reads.
What you should check
| Area | Requirement |
|---|---|
| Content | same main content as on desktop; accordions and tabs are fine |
| Access | do not block resources such as CSS, JavaScript and images in the robots.txt; do not load main content only after a user action |
| Robots meta tags | the same on mobile and desktop, especially for noindex and nofollow |
| Structured data | the same on both versions, with the mobile addresses in the markup |
| Title and description | equivalent on both versions |
| Images and videos | good quality, same alt text, stable addresses |
| Ads | no large ads at the top of the page that push the content down |
Responsive design is the easiest way
A mobile version is not required for content to appear in search. Google does recommend it explicitly, though, and you maintain it most easily with responsive design: one address, one version of the content, the layout adapts. For that you need the viewport meta tag.
<meta name="viewport" content="width=device-width, initial-scale=1">Special case: separate mobile addresses
If you have a separate mobile website, for example under an m. subdomain, the following also applies:
- Both versions return the same status for errors.
- Mobile pages have no URL fragments.
- Many desktop pages are not redirected to a single mobile page or the mobile home page.
- Both versions are verified in Google Search Console.
- Hreflang links connect mobile to mobile and desktop to desktop.
- The canonical of the mobile page points to the desktop address, the desktop page refers to the mobile one as an alternate (see duplicate content).
- The mobile server can handle higher crawl rates.
How to check it
- URL Inspection in Search Console shows how Google fetched a page and with which crawler.
- The settings of Search Console show whether your property has been switched to mobile-first.
- Compare the source code of the mobile and the desktop version, especially headings, texts, links and structured data.
Common mistakes
- Shortened mobile content: Texts, images or links that exist only on desktop are missing from the index.
- Blocked resources: If Google may not load CSS or JavaScript, it sees the page differently from visitors.
- Loading content only after a click or scroll: Google does not trigger user actions.
- Different structured data: If it is missing on mobile, rich results are lost.
- Mobile error pages: If the mobile version shows an error to all users or is blocked by robots.txt, the pages disappear from the index.
Related terms
- Core Web Vitals: measure user experience
- Page Experience: overall impression of a page
- JavaScript SEO: content that appears via script
- robots.txt: control access
Sources
- Google Search Central: Mobile-first indexing best practices
- Google Search Central Blog: Mobile-first indexing: final stage (June 3, 2024)