UX & Design
Apr 7, 20264 min readThe Mobile-First Checklist Every Website Needs
EP
Enzo P.
Founder, Roast My Site
62% of all web traffic is mobile. Yet most websites are still designed on desktop monitors and "made responsive" as an afterthought. Here's the definitive checklist for a mobile experience that converts.
Typography
☐Minimum 16px base font size (below this, iOS auto-zooms, breaking your layout)
☐Line height 1.5-1.7 for body text (cramped lines are unreadable on small screens)
☐Headlines no larger than 2.5rem on mobile (prevent horizontal overflow)
☐Sufficient contrast — WCAG AA minimum (outdoor lighting is brutal)
Buttons & Tap Targets
☐Minimum 44x44px tap target size (Apple's HIG recommendation)
☐At least 8px spacing between adjacent tap targets
☐Primary CTA visible without scrolling on mobile viewport
☐No hover-only states (there's no hover on touch)
Forms
☐Correct input types (type="email", type="tel", type="number") to trigger appropriate keyboards
☐Autocomplete attributes on name and email fields
☐Form submit button visible when keyboard is open
☐Labels above inputs, not placeholder-only (placeholders disappear when typing)
Navigation
☐Hamburger menu or bottom navigation bar (max 5 items)
☐Logo links back to home (users expect this)
☐Search accessible from main nav
☐No dropdown menus that require hover
Performance
☐Images optimized and served in WebP format
☐Core Web Vitals: LCP under 2.5s on mobile network
☐No render-blocking scripts
☐Fonts subset to only characters used
Layout
☐Single column layout on viewport widths below 768px
☐No horizontal overflow (test by setting viewport to 320px)
☐Sticky header doesn't consume more than 10% of viewport height
☐No fixed-width containers exceeding viewport width
Testing Protocol
Don't just resize your browser. Test on a real device — or at minimum, use Chrome DevTools device emulation with a throttled connection. Test with your non-dominant thumb. If you can complete your primary conversion action (signup, purchase, contact) one-handed, you pass.
If you want a quick automated check of your mobile experience, run your URL through Roast My Site — mobile experience is one of the 7 scored dimensions.
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