Mobile-First Design
A design approach that starts with the mobile screen and expands to desktop. Google indexes based on the mobile version. Over 60% of eCommerce traffic is mobile. Mobile-first is a priority for the majority of visitors.
In practice
Mobile-first means: when designing a page, view it on an iPhone 14 first, then on a MacBook. An element that looks stunning on desktop but breaks on mobile is broken for everyone. Google also ranks based on mobile experience.
Common misconception
'Responsive design = mobile-first.' No. Responsive means it adapts to any screen size. Mobile-first means planning from mobile first. A responsive site that wasn't designed mobile-first usually has a poor mobile experience despite adapting technically.
How to fix it
Poor mobile experience? (1) Google PageSpeed Insights → Mobile tab, (2) Check tap-target size — buttons at least 48×48px, (3) Check font size — 16px minimum, (4) Check navigation — is the hamburger menu clear? (5) Check forms — are fields big enough for a thumb?
Example
Bag store: desktop CR 3.1%, mobile CR 0.7%. Mobile audit: the ATC button was partly hidden on an iPhone SE. Fixed mobile CSS in 4 hours. Mobile CR rose to 1.9%. With 68% mobile traffic, that's $13,000 in additional revenue/month.
Priority
Test mobile experience right now on 3 device sizes: iPhone SE (375px), iPhone 14 (390px), Galaxy (412px). If mobile CR is below 60% of desktop CR, a mobile-first fix is urgently needed.
Related terms
Keep learning. Metrics that touch the same area:
- Responsive DesignTechA website that adapts to different screen sizes — desktop (1200px+), tablet (768px), mobile (375px). In 2024: 60%+ of traffic comes from mobile — responsive design is mandatory, not a nice-to-have.
- Core Web VitalsSEOThree site performance metrics: LCP (main content load < 2.5s), INP (interaction responsiveness < 200ms), CLS (visual stability < 0.1). Google factors these into rankings.
- API – Application Programming InterfaceTechA 'language' for communication between systems. A store connects via API to shipping providers, Klaviyo, and payment platforms. The API is the 'pipe' through which data flows.
- Headless CommerceTechAn architecture that separates the front end (what the customer sees) from the back end (catalog, payments, inventory). Gives full freedom in design and channel integration.
- CRM – Customer Relationship ManagementTechA system for storing customer data, communication history, and purchase history. Enables segmentation, personalization, service tracking, and lifecycle management. HubSpot, Salesforce, Klaviyo.
- CDP – Customer Data PlatformTechConsolidates customer data from multiple sources into a unified real-time profile. More advanced than a CRM — pulls behavioral events and enables instant segmentation.
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