SEO Technical: Mobile-Friendly

Guides mobile-first indexing optimization and mobile usability. Google uses the mobile version of pages for indexing and ranking; mobile-friendliness is a ranking factor.

When invoking: On first use, if helpful, open with 1–2 sentences on what this skill covers and why it matters, then provide the main output. On subsequent use or when the user asks to skip, go directly to the main output.

Scope (Technical SEO)

• Mobile-first indexing: Google primarily crawls and indexes mobile version

• Mobile adaptation: Responsive design, viewport, breakpoints

• Content parity: Mobile and desktop content should match (or mobile preferred)

• Mobile usability: Viewport, font size, touch targets, no intrusive interstitials

• AMP: Accelerated Mobile Pages—status and when to consider

Initial Assessment

Check for project context first: If .claude/project-context.md or .cursor/project-context.md exists, read it for site URL.

Identify:

• Site type: Responsive, separate AMP, dynamic serving

• Content parity: Does mobile show same content as desktop?

• Tools: GSC Mobile Usability report; Mobile-Friendly Test

Mobile-First Indexing Requirements

Requirement Action

Content parity Mobile version must include same primary content as desktop; avoid hiding key content on mobile

Structured data Same schema on mobile and desktop; ensure mobile URLs in schema

Metadata Same title, meta description on mobile

Media Images should be crawlable; avoid lazy-loading above-fold images

Responsive Design & Mobile Adaptation

Responsive design = Single HTML; CSS media queries adapt layout to screen size. Preferred for SEO: one URL, no duplicate content.

Principle Practice

Mobile-first Design for mobile first; enhance for desktop

Fluid layout Use % , vw , flex , grid ; avoid fixed pixel widths

Breakpoints Common: 320px, 768px, 1024px, 1280px; match device widths

Images Responsive images (srcset , sizes ); see image-optimization

Viewport

The viewport meta tag tells browsers how to scale and size the page on mobile. Required for mobile-friendly pages.

<meta name="viewport" content="width=device-width, initial-scale=1">

Attribute Purpose

width=device-width

Match viewport to device screen width

initial-scale=1

1:1 scale on load; prevents zoom

maximum-scale

Avoid disabling zoom (accessibility)

user-scalable=no

Avoid—hurts accessibility

Without viewport: Desktop layout shrunk; horizontal scroll; fails Mobile-Friendly Test. See page-metadata.

Mobile Usability Checklist

Element Guideline

Viewport See above; required for mobile-friendly

Font size 16px minimum for body text; avoid zooming to read

Touch targets Buttons/links ≥48×48px; adequate spacing between taps

Content width No horizontal scrolling; content fits viewport

Intrusive interstitials Avoid popups that block main content on mobile

Common Issues

Issue Fix

Content hidden on mobile Show critical content; avoid accordion/tabs for primary content

Flash / unsupported Replace with HTML5 alternatives

Text too small Use base font ≥16px; avoid font-size in px <12

Links too close Increase tap target size; add padding

Responsive vs. Separate URLs

Approach When Note

Responsive Preferred Single URL; same HTML, CSS media queries

Dynamic serving Same URL, different HTML by user-agent Ensure mobile content parity

Separate URLs m.example.com Use canonical + hreflang; see canonical-tag, page-metadata

Accelerated Mobile Pages (AMP)

AMP is a web component framework for fast-loading pages. Status (2024–2025): Still supported; no longer required for Top Stories or ranking.

Aspect Note

Ranking No ranking advantage over well-optimized responsive pages

Top Stories AMP no longer required since 2021; Core Web Vitals suffice

When to consider News sites, ad-heavy pages, very slow hosting—but responsive + CWV usually better

Alternative Responsive design + core-web-vitals optimization; SSR/SSG; see rendering-strategies

Recommendation: For most sites, prioritize responsive design and Core Web Vitals over AMP. AMP adds maintenance (separate AMP HTML); modern optimization offers similar performance with more flexibility.

Output Format

• Mobile Usability status: Pass/fail from GSC or Mobile-Friendly Test

• Responsive / viewport: Check viewport meta; breakpoints; fluid layout

• Content parity: Mobile vs desktop content check

• AMP: Only if legacy or specific use case

• Fixes: Prioritized by impact

Related Skills

• page-metadata: Viewport meta tag; required for mobile

• core-web-vitals: CWV measured on mobile; replaces AMP for Top Stories; LCP, INP, CLS

• canonical-tag: Separate mobile URLs; hreflang for mobile

• image-optimization: Responsive images; mobile LCP

• rendering-strategies: SSR/SSG for fast mobile load

• google-search-console: Mobile Usability report