Mobile-First Indexing
Session 7.4 · ~5 min read
Since 2019, Google has used mobile-first indexing for all new websites, and as of 2023, all websites are indexed mobile-first. This means Google primarily uses the mobile version of your page for indexing and ranking. The desktop version is secondary.
For entity authority, this has a direct implication: if your entity signals (schema markup, entity descriptions, NAP information, internal links) are present on desktop but missing on mobile, Google may never see them. Your mobile experience is your experience in Google's eyes.
What Mobile-First Indexing Means
(Secondary Crawl)"] C --> C1["Googlebot Smartphone
(Primary Crawl)"] C1 --> D["Google's Index
(Based on Mobile Content)"] B1 --> E["Used for
Desktop-Specific Signals Only"] D --> F["Rankings for
All Devices"] style C fill:#222221,stroke:#c8a882,color:#ede9e3 style C1 fill:#222221,stroke:#c8a882,color:#ede9e3 style D fill:#222221,stroke:#6b8f71,color:#ede9e3 style B fill:#222221,stroke:#8a8478,color:#ede9e3
Googlebot Smartphone is the primary crawler. It is the one that reads your content, processes your schema markup, follows your internal links, and evaluates your Core Web Vitals. Googlebot Desktop still crawls occasionally but is not the primary source for your index entry.
Key concept: Mobile-first indexing means the mobile version of your page IS your page in Google's index. If content or markup exists only on the desktop version, Google treats it as if it does not exist.
Common Mobile Problems That Hurt Entity Signals
Many websites inadvertently hide or degrade entity signals on mobile. Here are the most common problems.
| Problem | How It Happens | Entity Impact | Fix |
|---|---|---|---|
| Content hidden on mobile | CSS display:none or tabs/accordions that hide content by default on small screens | High. Google deprioritizes content that is hidden on mobile. | Make all entity-critical content visible by default on mobile. No hidden tabs for entity info. |
| Schema markup missing on mobile | Separate mobile site (m.example.com) does not include the same JSON-LD as desktop | Severe. Entity signals completely absent from indexed version. | Ensure identical schema markup on both versions. Better: use responsive design. |
| Different content on mobile vs. desktop | Mobile site shows abbreviated content or different text | High. Google indexes the mobile text, which may lack entity descriptions. | Serve the same content on both versions. Responsive design solves this by default. |
| Missing internal links on mobile | Mobile navigation is simplified, removing links to entity pages | Medium. Reduced internal linking weakens entity page authority. | Ensure mobile navigation includes links to all entity-critical pages. |
| Images missing on mobile | Mobile version removes images to save bandwidth | Medium. Entity-associated images not indexed. | Use responsive images (srcset) instead of removing images entirely. |
| Intrusive interstitials | Full-screen popups on mobile that block content | Medium. Google penalizes intrusive interstitials. | Use small banners instead. Never block the main content. |
| Unreadable text | Text too small to read without zooming on mobile | Low for entity signals, high for user experience. | Use a minimum font size of 16px for body text. Set proper viewport meta tag. |
| Tap targets too small | Buttons and links too close together or too small to tap accurately | Low for entity signals, high for user experience. | Minimum 48x48px tap targets with 8px spacing between them. |
The Mobile Audit Checklist
Use this checklist to verify your entity pages are fully optimized for mobile-first indexing.
| Audit Item | What to Check | How to Check | Pass/Fail |
|---|---|---|---|
| Responsive design | Site uses responsive layout, not a separate mobile site | Resize browser window. Or check for m.example.com redirects. | |
| Viewport meta tag | <meta name="viewport" content="width=device-width, initial-scale=1"> is present | View page source | |
| Same content on mobile | All text, headings, and entity descriptions visible on mobile | Compare mobile and desktop in Chrome DevTools | |
| Schema markup parity | Same JSON-LD appears in mobile HTML as desktop HTML | URL Inspection Tool in GSC (shows mobile render) | |
| Internal links preserved | Mobile navigation includes links to About, Contact, Services | Test mobile navigation manually | |
| Images visible on mobile | Logo, headshot, branded images load on mobile | Browse entity pages on a real phone | |
| No intrusive interstitials | No full-screen popups that block content on mobile | Browse site on mobile immediately after load | |
| Text readability | Body text at least 16px, no horizontal scroll | Mobile device test or Chrome DevTools mobile emulation | |
| Tap target sizing | All links and buttons at least 48x48px | Lighthouse mobile audit | |
| Page speed on mobile | LCP under 2.5s on mobile connection | PageSpeed Insights (mobile tab) |
Testing With Google's Tools
Google provides several tools specifically for mobile testing:
Approximately 60% of global web traffic comes from mobile devices. Yet only about 52% of websites are fully optimized for mobile. Even more concerning, only 44% of websites maintain schema markup parity between mobile and desktop. That means over half of all websites are potentially sending weaker entity signals to Google than they intend.
Chrome DevTools Device Mode: Press F12 in Chrome, click the device toggle icon, and select a mobile device. This simulates the mobile viewport and lets you see what Googlebot Smartphone sees.
URL Inspection Tool: In Google Search Console, the URL Inspection Tool shows you the rendered page as Googlebot sees it. Since Googlebot is mobile-first, this shows the mobile render.
PageSpeed Insights: Always check the "Mobile" tab in PageSpeed Insights. The mobile scores are what Google uses for ranking.
Responsive Design vs. Separate Mobile Site
If you are still running a separate mobile site (m.example.com), consider migrating to responsive design. Responsive design serves the same HTML to all devices and uses CSS media queries to adapt the layout. This automatically ensures content parity, schema parity, and link parity between mobile and desktop.
Separate mobile sites require maintaining two versions of every page, which is where content and markup discrepancies typically appear. Google recommends responsive design as the preferred approach.
Further Reading
- Google. "Mobile-First Indexing Best Practices." Google Search Central. developers.google.com/search/docs/crawling-indexing/mobile/mobile-sites-mobile-first-indexing
- Google. "Mobile Usability Report." Google Search Central. support.google.com/webmasters/answer/9063469
- Google. "Responsive Web Design Basics." web.dev. web.dev/articles/responsive-web-design-basics
- Illyes, Gary. "Mobile-First Indexing Is Now Default." Google Search Central Blog. developers.google.com/search/blog
Assignment
- Open your homepage in Chrome DevTools Device Mode (F12, click device toggle). Compare the visible content to the desktop version. Is any entity-critical content hidden, collapsed, or missing?
- View the source of your homepage on mobile (or use URL Inspection Tool in GSC). Verify that your Organization/Person schema markup is present and identical to the desktop version.
- Test your mobile navigation. Can you reach your About page, Contact page, and Service pages from the mobile menu? If any are missing, add them.
- Run PageSpeed Insights on your homepage using the Mobile tab. Record the LCP, INP, and CLS scores for mobile specifically.
- Complete the Mobile Audit Checklist above for your homepage, About page, and Contact page. Fix any failures you discover.