SEO

Mobile-First Indexing

Q: What is mobile-first indexing?

Mobile-First Indexing means that Google primarily uses the mobile version of a website for indexing and ranking. This has applied to all new sites since 2020 and to all existing ones since 2023. The desktop version is only of secondary relevance.

Q: What does that mean for my website?

The mobile version must be complete. If the mobile version has less content, fewer images or less structured data than desktop, the site loses ranking signals. Responsive design is the safest solution — the same HTML for all devices.

Q: How do I check mobile friendliness?

Via the mobile-friendly test (formerly search.google.com/test/mobile-friendly, now integrated into the GSC) and the Lighthouse report. The Rankmio SEO audit checks mobile rendering, tap targets, viewport configuration and font sizes automatically.

Q: Is there still desktop-only indexing?

For the last few per cent of sites, yes — those Google cannot crawl cleanly on mobile for technical reasons. In practice, all sites have been indexed mobile-first since the end of 2023. Anyone still aiming for desktop-first is ignoring the reality of Google.

Also known as: Mobile-First Index, Mobile-first indexing

Mobile-First Indexing means that Google uses the mobile crawler (Googlebot Smartphone) as the main source for crawling, indexing and ranking calculation. Anything not visible on the mobile version effectively does not exist for Google. The rollout began in 2018 for new domains, was 99 % complete at the start of 2024 and has been binding for all websites since July 2024. Anyone still running a mobile version with reduced content in 2026 will see it in the rankings.

Practical consequences

Content parity — mobile and desktop must show the same content, the same H1/H2/texts, the same images with ALT tags, the same structured data.
Lazy loading with care — lazy-loaded content must be able to load for Googlebot Smartphone (Intersection Observer, no user-interaction trigger).
Complete images — not a reduced mobile gallery, but responsive image handling.
Identical structured data — Schema.org markup the same on mobile and desktop.
Mobile page speed — Core Web Vitals are measured from the mobile profile. Mobile is usually slower — so optimise it as a priority.

Classic mobile-first mistakes

Reduced mobile content — tabs, accordions with ”read more”, hidden sections that desktop shows and mobile does not.
Different images/videos — a smaller selection on mobile.
Missing footer links and sitelinks on mobile (this still happens).
Mobile-specific 404s on AMP pages that do not exist on desktop.
Aggressive mobile interstitials — cookie and newsletter pop-ups that take up the whole screen. A direct negative signal.
Hard-to-tap buttons — touch targets smaller than 48×48 px are downgraded in Page Experience.

Mobile-first in Search Console

In the GSC under ”Settings” you can see the active crawler — for most sites ”Smartphone” is listed as primary. URL inspection shows the rendered mobile view under ”Test live URL”, including console errors and the content actually loaded. Discrepancies between the live test (what Google sees) and the visual mobile site (what the user sees) are the most important diagnostic source for mobile-first problems.

Example from practice

Example: In 2018, a magazine still had a separate mobile subdomain (m.example.de) with shortened texts. Despite the mobile-first rollout in 2018–2019, that was just about sufficient. In 2024 visibility collapses: 60 % of clicks lost within 6 months. After migration to responsive design with full content parity, visibility recovers to 90 % after 4 months. Anyone who does not take mobile-first seriously loses ground systematically.

Frequently asked questions

What is mobile-first indexing?

Mobile-First Indexing means that Google primarily uses the mobile version of a website for indexing and ranking. This has applied to all new sites since 2020 and to all existing ones since 2023. The desktop version is only of secondary relevance.

What does that mean for my website?

The mobile version must be complete. If the mobile version has less content, fewer images or less structured data than desktop, the site loses ranking signals. Responsive design is the safest solution — the same HTML for all devices.

How do I check mobile friendliness?

Via the mobile-friendly test (formerly search.google.com/test/mobile-friendly, now integrated into the GSC) and the Lighthouse report. The Rankmio SEO audit checks mobile rendering, tap targets, viewport configuration and font sizes automatically.

Is there still desktop-only indexing?

For the last few per cent of sites, yes — those Google cannot crawl cleanly on mobile for technical reasons. In practice, all sites have been indexed mobile-first since the end of 2023. Anyone still aiming for desktop-first is ignoring the reality of Google.

Used in Rankmio for

Mobile-friendly audit in the SEO check

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Last updated: 2026-06-17 · Browse all glossary entries