Mobile SEO
Mobile-First Index Tool
Google indexes the mobile version of your pages. Check that it carries everything the desktop version does.
- Fetched live by our server
- Nothing stored
The tool
Enter the desktop URL, and the mobile URL too if your site uses separate mobile pages.
Loading the tool…
The URL you enter is sent to our server, which requests that page from the public internet and returns the response to your browser for analysis. We do not store the URL or the response, and we do not add either to analytics. Requests come from our server, not from your device or from the crawlers being simulated, so a site that blocks data-centre addresses or verifies crawlers by IP may answer differently.
What this tool checks
- Main content length and similarity between the two versions
- Title, meta description, H1 and the number of H2 sections
- Internal links and images with alt text
- JSON-LD structured data types present on desktop but missing on mobile
- Canonical URLs, robots directives and hreflang annotations
- For separate mobile URLs: the desktop rel=alternate media link and the mobile canonical back to desktop
- For dynamic serving: the Vary: User-Agent header
- The mobile viewport configuration
How to read the results
- Check the detected setup: responsive, dynamic serving or separate mobile URLs. The checks that apply depend on it.
- Fix High findings first. Content, structured data or robots differences on mobile change what Google indexes.
- Use the comparison table to see the exact values on each side.
- Re-run after changes, ideally with the Googlebot profiles ticked.
About this tool
What mobile-first indexing means for your pages
Google crawls and indexes the web with its smartphone crawler and uses the mobile version of a page for indexing and ranking. Google completed the move for the web as a whole, and sites that cannot be accessed on mobile risk not being indexed at all. In practice this means that whatever is missing from your mobile page is, as far as Google is concerned, missing from your site.
Fully responsive sites usually serve the same HTML to every device, so parity is automatic. Problems appear on sites that serve different HTML to phones, either from the same URL (dynamic serving) or from separate URLs such as m.example.com.
How this tool compares the two versions
It fetches the desktop URL with a desktop user agent and the mobile URL, or the same URL if you leave it blank, with a smartphone user agent. By default those are Googlebot Desktop and Googlebot Smartphone. It then compares the facts Google relies on:
- Content. Main content word counts and a similarity score. Google asks for the same content on mobile, including text, images and video.
- Metadata. Title and meta description should be equivalent.
- Headings and links. Missing sections and missing internal links on mobile mean less for Google to understand and follow.
- Structured data. Structured data should be on both versions, with URLs updated to the mobile URLs where you use separate pages.
- Robots and canonical. A
noindexon mobile only is the most damaging mistake in this area.
Separate mobile URLs
If you run separate mobile pages, Google needs to know they belong together. The desktop page carries:
<link rel="alternate" media="only screen and (max-width: 640px)" href="https://m.example.com/page">and the mobile page points back with:
<link rel="canonical" href="https://www.example.com/page">The tool checks both. It also notices when the mobile request is redirected to a different host and treats the site as using separate URLs.
Dynamic serving
When the same URL returns different HTML by device, send Vary: User-Agent so caches and CDNs keep the versions apart. Without it, a cache can hand the desktop page to a phone, or the reverse, and crawlers can see a mix.
What the result does not tell you
A clean comparison shows that the two responses match on the checked signals today. It cannot show what Google has stored, when it last crawled, or how it ranks the page. Use Search Console URL Inspection for that.
Moving to responsive design
If you maintain separate mobile pages, every new page has to be built, annotated and kept in step twice. Moving to a single responsive page removes that whole class of problem. When you migrate, redirect each mobile URL to its responsive equivalent with a 301, remove the alternate and mobile canonical annotations, and run this tool on a sample of pages before and after.
Limits and honest caveats
- This is a technical comparison of two HTTP responses. It does not access Google index data and cannot tell you which version Google has indexed.
- Requests come from our server. Sites that verify Googlebot by reverse DNS will send this tool their visitor version.
- JavaScript is not executed. If your mobile content is built by JavaScript, compare rendered output with Fetch & Render.
- Content hidden behind tabs or accordions counts as present, because it is in the HTML, which matches how Google treats it.
What people use it for
- Checking an m-dot site for missing content, links or structured data
- Confirming the alternate and canonical annotations between desktop and mobile URLs
- Making sure a dynamic serving setup sends Vary: User-Agent
- Auditing a redesign where the mobile layout drops sections
- Catching a noindex or different canonical that only applies to phones
Documentation and references
Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
No. It compares two live responses. For what Google stored, use the URL Inspection tool in Search Console.
Yes, briefly. It confirms both user agents get the same HTML, which catches CDN rules or plugins that serve phones something different.
Not for this comparison. The content is in the HTML, and Google indexes content in collapsed sections on mobile.
Some servers vary content for crawlers specifically. The Googlebot profiles show what a request identifying as Googlebot receives.
Yes. Enter it in the mobile URL field and the separate-URL checks apply.
Documentation last reviewed: by the Best Web Developer engineering team.
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