Official statement
Other statements from this video 25 ▾
- □ Does Google really experience delays in discovering JavaScript links?
- □ Why does Google ignore your canonical tags when the raw HTML contradicts the rendered output?
- □ Does a raw HTML noindex really prevent JavaScript rendering by Google?
- □ Can you really modify title, meta, and links on the client side with JavaScript without risks?
- □ Is client-side JavaScript really holding back your SEO performance?
- □ Raw HTML vs Rendered: Does Google really not care?
- □ Does Google AdSense really penalize your site's speed like any other third-party script?
- □ Should you be worried about 'other error' issues with images in the Search Console?
- □ Should you prioritize user agent or viewport detection for your separate mobile versions?
- □ Do JavaScript navigation links really affect your site's SEO?
- □ Can you really lose control of your canonical by leaving the href attribute empty at load time?
- □ Does Google really use different crawlers for its SEO testing tools?
- □ Should you really stop fearing JavaScript for SEO?
- □ Do JavaScript links really slow down Google's discovery process?
- □ How can a different canonical tag between raw HTML and rendered output destroy your canonicalization strategy?
- □ Can you really remove a noindex via JavaScript without risking de-indexation?
- □ Is it truly safe to modify meta tags and links with JavaScript without risking your SEO?
- □ Do Google products really get a hidden SEO advantage in search results?
- □ Should you be concerned about 'other' errors in the URL Inspection Tool?
- □ Does Google really overlook your images during web search rendering?
- □ User agent or viewport: Does Google really differentiate for mobile indexing?
- □ Do JavaScript-generated links truly pass ranking signals like traditional HTML links?
- □ Can an empty HTML canonical tag mistakenly force Google to auto-canonicalize your page?
- □ Can the Mobile-Friendly Test really substitute the URL Inspection Tool for auditing mobile crawling?
- □ Why does Google ignore your desktop structured data after switching to mobile-first indexing?
Once a site switches to mobile-first indexing, Google exclusively uses the structured data from the mobile version to generate all rich results—including those displayed on desktop. Before migration, each version (mobile and desktop) retains its own structured data for its context. Specifically, if your schema.org differs between mobile and desktop, only the mobile version will matter after the switch.
What you need to understand
What does Google mean by "mobile-first indexing" and how does it relate to structured data?<\/h3>
Mobile-first indexing means that Googlebot prioritizes crawling and indexing the mobile version of your site, even for desktop searches. This evolution, which started several years ago, is based on the observation that the majority of traffic now comes from smartphones.<\/p>
The direct consequence for structured data: once the migration is completed, Google will only read the schema.org markup present in your mobile version. Rich snippets, carousels, FAQ panels—everything relies on what Googlebot mobile detects. If your desktop version contains more complete or different schema.org data, it will be ignored.<\/p>
Before the switch to mobile-first indexing, Google applied a compartmentalized logic: the structured data from the desktop version were used to generate the rich results displayed on computers, while those from the mobile version were used for smartphones. Two indexes, two sources of markup.<\/p>
This approach theoretically allowed for content to be differentiated based on context, but also led to inconsistencies: a product could appear with one price in a rich snippet on mobile and another on desktop if the tags diverged. Since migration, this complexity has disappeared—at the cost of increased demands on the mobile version.<\/p>
Many sites have historically prioritized their desktop version for complete structured data: enriched articles with author, publication date, high-resolution images, detailed breadcrumbs. The mobile version, designed for lightweight presentation, sometimes carries a lighter or even incomplete markup.<\/p>
The result: after migrating to mobile-first indexing, these sites lose rich snippets on desktop without understanding why. Google no longer crawls the desktop version to extract the schema.org—and the Search Console does not always clearly signal this transition. This is a frequent blind spot in technical audits.<\/p>
How did Google behave before this migration?<\/h3>
Why does this unification pose problems for some sites?<\/h3>
SEO Expert opinion
Is this statement consistent with on-the-ground observations?<\/h3>
Yes, and it’s actually a recurring friction point in audits. We regularly observe sites migrated to mobile-first indexing that lose their rating stars, FAQ panels, or breadcrumbs in desktop SERPs—even though everything worked previously. The cause: a schema.org markup present only in the desktop version, or degraded on mobile for performance reasons.<\/p>
Google has been communicating about this topic for years, but the reality is that many technical teams still maintain distinct templates between mobile and desktop. And when responsive design is not total, structured data rarely follows suit. Poorly configured CMS exacerbate the problem: some schema.org modules only activate on desktop by default.<\/p>
Martin Splitt's statement is clear, but it leaves one technical point in the shade: what happens if the mobile version uses deferred JavaScript rendering to inject structured data? Does Googlebot mobile see them systematically? [To be verified]— in practice, we see that some sites with client-side JS hydration have their schema.org poorly indexed, especially if rendering takes more than 5 seconds.<\/p>
Another nuance: Google indicates it uses data from the mobile version "for all rich results," but does not clarify if content differences between mobile and desktop can affect eligibility. Example: a complete article on desktop, truncated on mobile with a "Read more" button. If the Article schema.org markup points to the truncated content, does Google consider the article incomplete? Yes, in some cases—and the loss of the rich snippet follows.<\/p>
Let’s be honest: there is no explicit exception in the statement. All sites migrated to mobile-first indexing follow this logic. But in practice, we observe atypical behaviors on highly authoritative domains or major news sites: Google sometimes seems to retain reading desktop structured data for certain types of content (events, job listings).<\/p>
These cases remain marginal and likely tied to accumulated trust signals rather than an exception to the rule. Don’t count on this for your site. Another situation where this rule loses relevance: sites that have never had a distinct desktop version—fully responsive from the start. In that case, the question doesn’t even arise.<\/p>
What nuances should we add to this rule?<\/h3>
In what cases does this rule not apply?<\/h3>
Practical impact and recommendations
What practical steps should be taken to align structured data?<\/h3>
First step: audit the parity between your mobile and desktop versions. Use Google’s rich results testing tool in mobile mode, then compare it with a desktop crawl of your strategic pages. Screaming Frog, Oncrawl, or a Python script with Beautiful Soup can extract and diff schema.org tags between the two versions.<\/p>
If you detect discrepancies, prioritize the mobile version: it is the authoritative version. Add or complete missing structured data—and if page weight or loading time constraints force you to lighten, choose the types of schema that are most impactful for your business (Product, Article, Recipe, Event depending on your sector).<\/p>
Don’t fall into the trap of blindly copying and pasting desktop structured data to mobile without adaptation. Some fields like "image" must point to URLs optimized for mobile (appropriate resolution, WebP format), otherwise Google may reject the markup or not display the rich snippet.<\/p>
Another common mistake: maintaining structured data in JSON-LD only in the of the desktop version, and forgetting it on mobile. If your CMS injects JSON-LD via a plugin or module, ensure that it activates properly on all versions. Microdata tags in the are less problematic, but are more cumbersome to maintain.<\/p>
Consult the Search Console, under "Settings" > "Crawling" to confirm that your site has indeed switched to mobile-first indexing. Then, navigate to "Enhancements" to see if Google correctly detects your structured data: products, recipes, FAQs, articles, events.<\/p>
Also test in real conditions: perform searches on your primary keywords from a desktop and check if the expected rich snippets appear. If you notice a disappearance, it's probably because the mobile version does not carry the appropriate markup. A quick test with the URL Inspection Tool in Googlebot mobile mode usually clears up any doubt.<\/p>
What mistakes should be avoided during this harmonization?<\/h3>
How can I check if my site is compliant after migration?<\/h3>
❓ Frequently Asked Questions
Mes structured data desktop disparaissent-elles complètement après la migration mobile-first ?
Comment savoir si mon site a basculé dans l'index mobile-first ?
Puis-je avoir des structured data différentes entre mobile et desktop sans pénalité ?
Les structured data injectées en JavaScript côté client sont-elles bien crawlées en mobile-first ?
Faut-il dupliquer toutes les structured data desktop sur mobile, même si ça alourdit la page ?
🎥 From the same video 25
Other SEO insights extracted from this same Google Search Central video · published on 26/04/2021
🎥 Watch the full video on YouTube →Related statements
Get real-time analysis of the latest Google SEO declarations
Be the first to know every time a new official Google statement drops — with full expert analysis.
💬 Comments (0)
Be the first to comment.