# Separate mobile URLs

Category: [Technical SEO](https://seo-geo-glossary.com/en/glossary/category/technical-seo/) › [HTML, mobile & accessibility](https://seo-geo-glossary.com/en/glossary/category/technical-seo/html-mobile-accessibility/) · Also known as: m-Dot

**Separate mobile URLs** are a mobile setup where desktop and phone visitors receive different HTML at different URLs, usually on a subdomain such as `m.example.com` (hence "m-dot"). Google names this next to responsive design and dynamic serving.

## How does the setup work?
Google's documentation uses the desktop URL as the canonical and the mobile URL as its alternate. Both versions need matching `rel=canonical` and `rel=alternate` annotations, and Google notes that user-agent and `Vary` headers are used to send users to the right version. Google recommends responsive design instead, because it is the easiest setup to maintain.

Google's checklist for separate URLs includes:
- error pages return the same status on desktop and mobile
- the mobile version contains no URL fragments
- content is equivalent on both versions
- hreflang links connect mobile URLs to mobile URLs and desktop to desktop
- robots.txt rules work for both versions
- both versions are verified in Search Console
- the mobile server can handle the added crawl load

## Example
On the desktop page:
```html
<link rel="canonical" href="https://www.example.com/page">
<link rel="alternate" media="only screen and (max-width: 640px)" href="https://m.example.com/page">
```
On the mobile page:
```html
<link rel="canonical" href="https://www.example.com/page">
```

## Common mistakes
- The mobile page shows less content than desktop, although Google indexes the mobile version.
- Error pages return a different status code on the mobile subdomain.

## Mobile site configurations compared

| Configuration | URL | HTML | Technical signals | Google's position |
|---|---|---|---|---|
| Responsive design | same URL on every device | same HTML; the layout adapts to the screen size | none needed; content and metadata are identical on mobile and desktop | recommended as the easiest pattern to implement and maintain |
| Dynamic serving | same URL on every device | different HTML per device, chosen by user-agent detection | Vary: user-agent response header | supported; the mobile version needs the same content as desktop |
| Separate mobile URLs | a separate URL per device, e.g. m.example.com | different HTML per device | mobile page: rel="canonical" to the desktop URL; desktop page: rel="alternate" with media to the mobile URL; redirects based on user agent and Vary | supported; the desktop URL is always canonical, and hreflang links mobile to mobile and desktop to desktop |

Sources: [Google Search Central: Mobile site and mobile-first indexing best practices (last updated 2025-12-10)](https://developers.google.com/search/docs/crawling-indexing/mobile/mobile-sites-mobile-first-indexing); [MDN: Vary header](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Vary). Last checked: October 8, 2026

## Related terms

- [AMP (Accelerated Mobile Pages)](https://seo-geo-glossary.com/en/glossary/amp/index.md)
- [Responsive design](https://seo-geo-glossary.com/en/glossary/responsive-design/index.md)
- [Mobile-first indexing](https://seo-geo-glossary.com/en/glossary/mobile-first-indexing/index.md)
- [Dynamic serving](https://seo-geo-glossary.com/en/glossary/dynamic-serving/index.md)
- [Vary header](https://seo-geo-glossary.com/en/glossary/vary-header/index.md)
- [Canonical tag](https://seo-geo-glossary.com/en/glossary/canonical-tag/index.md)
- [hreflang](https://seo-geo-glossary.com/en/glossary/hreflang/index.md)

## Sources

- [Mobile sites and mobile-first indexing – Google Search Central](https://developers.google.com/search/docs/crawling-indexing/mobile/mobile-sites-mobile-first-indexing)
- [Consolidate duplicate URLs – Google Search Central](https://developers.google.com/search/docs/crawling-indexing/consolidate-duplicate-urls)

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Last updated: October 8, 2026
URL: https://seo-geo-glossary.com/en/glossary/separate-mobile-urls/