Mobile-first indexing is a change in how Google indexes sites. Before, Google primarily indexed the desktop version and used it for ranking. From 2024 Google indexes all sites through the mobile version β meaning Googlebot arrives as a mobile bot, and what you show on a mobile screen is what enters Google's index. This is a major change and many owners still don't understand or implement it correctly.
Why Google moved to mobile-first
Historical reasons. Before 2015 desktop internet use was larger than mobile. In 2016 mobile passed desktop, and mobile traffic has grown every year. Today 60%+ of internet traffic is mobile; in some markets (India, Africa, partly Uzbekistan) 80%+.
This behavioural shift forced Google to adapt. If 60-80% of users arrive via mobile, indexing should be from the mobile too β otherwise results may mismatch.
How mobile-first works
Technically, Smartphone Googlebot (with \"Mobile\" in User Agent) visits the site, renders it in mobile mode and adds the result to the index.
So: whatever your desktop has, if the content is missing or different on mobile, Google does not index it. Desktop with 3000 words, mobile with 500 words β Google indexes the 500-word version.
The biggest mistake β different mobile and desktop content
Many sites between 2010-2018 had separate mobile versions (m.example.com) with cut-down content. With mobile-first this is a serious SEO problem β Google indexes the trimmed mobile.
Solution β responsive design. One HTML/CSS that adapts to the screen. Bootstrap and Tailwind use this as default. If you still have an m. mobile version, switch to responsive urgently.
Responsive design and the viewport meta
First step β viewport meta in head: <meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">.
Then CSS media queries for different screens. Small β 1 column, larger β 2 or 3. Content stays the same; only the layout changes.
Mobile-friendly testing
Google Mobile-Friendly Test (search.google.com/test/mobile-friendly) β enter the URL and see how Google views it on mobile. Green β OK, red β issues.
In GSC the \"Mobile Usability\" report shows all pages' status. Errors like \"Text too small to read\", \"Clickable elements too close together\", \"Content wider than screen\" point to specific problems.
Mobile performance β Core Web Vitals
With mobile-first, mobile site speed matters more. LCP, INP, CLS β three ranking factors, measured on mobile. A fast desktop may be slow on mobile.
Optimisation: different image sizes for mobile (srcset), lazy loading, minify JS/CSS, critical CSS inline, CDN edge cache. PageSpeed Insights mobile shows real user data.
Mobile UX
Google also rates UX. Tap targets at least 48x48 px, button spacing 8 px, text 16 px, no intrusive popups. All in Page Experience.
The main mistake β \"intrusive interstitial\" β full-screen popup on opening a mobile page. Google penalises.
Local SEO and mobile
Local queries (\"restaurant nearby\", \"pharmacy open now\") are mostly mobile. Google prioritises Google Business Profile data. For local businesses GBP must be complete and active.
In the local pack photos, reviews, hours, directions, phone are visible. The user can get the info without visiting the site at all.
Sayt.uz practice
Sayt.uz was mobile-first from the start. Desktop content is not trimmed; same content. Responsive layout, viewport meta, mobile Core Web Vitals green (LCP 1.8s, INP 120ms, CLS 0.03).
Statistics: 73% mobile, 24% desktop, 3% tablet. Mobile dwell time is higher than desktop. Mobile-first design serves these users well.