Short answer: Mobile-first indexing means Google uses the mobile version of a site’s content, crawled with its smartphone agent, for indexing and ranking. A mobile version isn’t required to appear in Google’s results, but Google very strongly recommends one.
Three ways to serve a mobile site
| Setup | How it works | What Google says |
|---|---|---|
| Responsive design | The same HTML on the same URL for every device | Recommended: the easiest to build and maintain |
| Dynamic serving | The same URL, with different HTML chosen by the user agent | Google’s mobile guide is written for this setup |
| Separate URLs | Different HTML on a separate URL for each device | Google’s mobile guide is written for this one too |
From Google Search Central, “Mobile site and mobile-first indexing best practices”, read November 3, 2026.
Dynamic serving relies on the Vary: user-agent header to send different HTML to each device. With responsive design, Google notes, the content and metadata are already the same on mobile and desktop.
What has to match on mobile
The mobile page should carry the same content as the desktop one. A different design is fine, such as moving content into accordions or tabs, as long as the content is equivalent.
Use the same clear headings, the same structured data and an equivalent title and meta description on both. If you have to choose, Google says to start the structured data with Breadcrumb, Product and VideoObject.
Keep the same robots meta tags on both versions. A different noindex or nofollow on mobile may stop Google from crawling and indexing the page.
Images need the same alt text on mobile, and using the same image URLs avoids a temporary loss of image traffic. Google also won’t load primary content that needs a swipe, a click or typing to appear.
How to check your site for mobile-first indexing
- Find out which of the three setups your site uses.
- Open a page on your phone and compare its text with the desktop version.
- Check that the title, meta description and headings match.
- Make sure the robots meta tag is the same on both, with no extra noindex or nofollow.
- Confirm the structured data is present on mobile too.
- Make sure robots.txt doesn’t block resources the mobile page needs, such as CSS, JavaScript or images.
- Look at the rendered page in the URL Inspection tool to see what Google sees.
Our guides to the URL Inspection tool, lazy loading images and alt text go deeper into steps 7, 5 and 3.
What we found on our own pages
Between 7:20 and 7:25 AM on November 3 we read the 314 pages in our sitemap twice as a visitor: once with an iPhone browser and once with a desktop browser.
All 314 returned the same title, meta description, robots meta tag, canonical, H1 and H2 headings, structured data types and image alt texts in both reads. None sent a Vary: user-agent header, which is consistent with a responsive site that serves one HTML to every device.
Our robots.txt blocks only /wp-admin/, so the CSS, JavaScript and images our pages need stay open to Google.
A browser user agent isn’t Googlebot, so for single pages we also look at the rendered page in the URL Inspection tool.
Before you publish a page
- The mobile page has the same content as desktop.
- Title, meta description and headings match.
- The robots meta tag is the same on both.
- Structured data is on the mobile page too.
- Images keep their alt text and URLs on mobile.
- No primary content waits for a click or a swipe to load.
RememberGoogle indexes what your mobile page shows. Keep the same content, headings, metadata and robots tags on both versions, and use the URL Inspection tool to see the page as Google renders it.
If you want us to check how Google sees your site on mobile, see our technical SEO service.
Quick answers about mobile-first indexing
Do I need a separate mobile site for Google?
No. Google says a mobile version isn’t required for your pages to appear in its results, though it very strongly recommends one. Its preferred setup is responsive design: the same HTML on the same URL for every device.
What happens if my mobile pages have less content than desktop?
Google uses the mobile version for indexing, so it says to expect some traffic loss, because it gets less information from the page. Instead of removing content on mobile, it suggests moving it into accordions or tabs.
Does Google index content inside tabs or accordions?
Google suggests accordions or tabs to save space on mobile, as long as the content is equivalent to desktop. What it won’t load is primary content that only loads after a swipe, a click or typing.
Why does the robots meta tag matter for mobile-first indexing?
Google asks for the same robots meta tags on mobile and desktop. If the mobile page carries a different one, especially noindex or nofollow, Google may fail to crawl and index the page.
How can I see my page the way Google sees it?
Use the URL Inspection tool in Search Console and look at the rendered page, which Google describes as how it sees your page. Check that the content you need is visible there.
Sources
Read on November 3, 2026. Google Search Central: Mobile site and mobile-first indexing best practices. Our own case: the pages in our sitemap and our robots.txt, read on November 3, 2026.