Mobile-First Means More Than Responsive
Google has been mobile-first indexing for years now: the mobile version of your page is the one Googlebot evaluates. A site that looks great on desktop but renders at desktop width on phones with overflowing tables and 8-pixel text will rank as poorly as if it were broken outright.
Signals that matter
- Viewport meta with width=device-width. Without it the browser assumes a 980px desktop layout.
- Responsive images. srcset/sizes serve appropriately sized assets for each device.
- No fixed-width containers. A single
width: 1200pxcan break the entire layout. - Input types. Using
type="email"ortelshows a friendlier mobile keyboard. - Touch icons and theme-color. Polish for installed/pinned web apps.
Limitations of static analysis
This tool reads the served HTML — it does not run JavaScript. If your layout is built entirely in client-side React or by a framework that hydrates after load, the signals above may live in inline styles or runtime CSS instead. Consider this a fast first-pass; pair it with Chrome DevTools and Lighthouse for the full picture.