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

Project context: Read root contextus.md when present and load only the modules relevant to this task. Without Contextus, use available project material or user-provided facts and ask for missing information; do not create a parallel context system.

Identify:

1. Site type: Responsive, separate AMP, dynamic serving
2. Content parity: Does mobile show same content as desktop?
3. 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