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). Several individual audit names 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 is unchanged and still applies; only the report format moved. 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 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) < 200ms. User interactions must feel instant. Reduce JavaScript execution time and break up long tasks.
• CLS (Cumulative Layout Shift) < 0.1. Content must not jump around. Set explicit dimensions on 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.