Web quality audit
/SKILLComprehensive web quality audit covering performance, accessibility, SEO, and best practices.
--- name: web-quality-audit description: Comprehensive web quality audit covering performance, accessibility, SEO, and best practices. Use when asked to "audit my site," "review web quality," "run a Lighthouse audit," "check page quality," or "optimize my website." license: MIT metadata: author: web-quality-skills version: "1.0" --- # Web quality audit Comprehensive quality review based on Google Lighthouse audits. Covers Performance, Accessibility, SEO, and Best Practices across 150+ checks. > Lighthouse v13 note (Oct 2025+). Lighthouse has migrated the Performance category from per-opportunity audits to Performance Insight Audits ([announcement](https://developer.chrome.com/blog/moving-lighthouse-to-insights)). Several individual audit names that this skill historically referenced:First Meaningful Paint, No Document Write, Uses Passive Event Listeners, Uses Rel Preload:have been removed or merged. The underlying advice remains unchanged and still applies; only the report format has changed. The CLS-related audits (“layout shifts,” “non-composited animations,” “unsized images”) are now consolidated into a single “cls-culprits-insight,” and image audits are merged into “image-delivery-insight.” Treat older Lighthouse JSON output as a superset, not a contradiction. ## How it works 1. Analyze the provided code/project for quality issues 2. Categorize findings by severity (Critical, High, Medium, Low) 3. Provide specific, actionable recommendations 4. Include code examples for fixes ## Audit categories ### Performance (40% of typical issues) Core Web Vitals : Must pass for a good page experience: LCP (Largest Contentful Paint) < 2.5s. The largest visible element must render quickly. Optimize images, fonts, and server response time. INP (Interaction to Next Paint) < 200 ms. User interactions must feel instant. Reduce JavaScript execution time and break up long tasks. CLS (Cumulative Layout Shift) < 0.1. Content must not shift around. Set explicit dimensions for images, embeds, and ads. Resource Optimization: Compress images. Use WebP/AVIF with fallbacks. Serve correctly sized images via srcset. Minimize JavaScript. Remove unused code. Use code splitting. Defer non-critical scripts. Optimize CSS. Extract critical CSS. Remove unused styles. Avoid @import. Efficient fonts.* Use font-display: swap. Preload critical fonts. Subset to needed characters. Loading Strategy: Preconnect to origins.* Add <link rel="preconnect"> for third-party domains. Preload critical assets. LCP images, fonts, and above-the-fold CSS. Lazy load below-the-fold content. Images, iframes, and heavy components. Cache effectively. Long cache TTLs for static assets. Immutable caching for hashed files. ### Accessibility (30% of typical issues) Perceivable: Text alternatives. Every <img> has meaningful alt text. Decorative images use alt="". Color contrast. Minimum 4.5:1 for normal text, 3:1 for large text (WCAG AA). Do not rely on color alone. Use icons, patterns, or text alongside color indicators. Captions and transcripts. Videos have captions. Audio has transcripts. Operable: Keyboard accessible. All functionality is available via the keyboard. No keyboard traps. Focus visible. Clear focus indicators are displayed on all interactive elements. Skip links. Provide a "Skip to main content" link for keyboard users. Sufficient time. Users can extend time limits. No content that advances automatically without controls. Understandable: Page language. Set the `lang attribute on <html>`. Consistent navigation. The same navigation structure across pages. Error identification. Form errors are clearly described and associated with the relevant fields. Labels and instructions. All form inputs have associated labels. Robust: Valid HTML. No duplicate IDs. Properly nested elements. ARIA used correctly. Prefer native elements. ARIA roles match behavior. Name, role, value. Interactive elements have accessible names and correct roles. ### SEO (15% of typical issues) Crawlability: Valid robots.txt.* Does not block important resources
