Mobile-First Indexing

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.