Site Speed Optimization

Site Speed Optimization

Audit HTML-level factors that affect page load speed.

Note: Render-blocking scripts, image dimensions/lazy loading, preconnect hints, and font loading are handled by the core-web-vitals skill. Do not duplicate those checks here.

1. Total script count

Count all <script src="..."> elements:

• More than 10 external scripts → ⚠️ WARN "Consider bundling or removing unused scripts"
• 10 or fewer → ✅ PASS

2. Inline CSS volume

Measure total character count of all style="..." attributes + <style> element contents:

3. Stylesheet loading

• Count <link rel="stylesheet"> elements
• If stylesheets > 3 → ⚠️ WARN "Consider combining CSS files"

4. Image alt text

5. Image formats

• Images with .jpg, .jpeg, .png, .gif extensions → ⚠️ WARN "Consider WebP or AVIF for smaller file sizes"

6. Next.js Image component

• Images not using /_next/image src → ⚠️ WARN "Consider using Next.js <Image> component for automatic optimization"
• Skip this check if the site is not a Next.js project

Edge cases

• Inline <script> tags (no src) should be counted separately from external scripts — they contribute to page weight but not network requests
• <style> elements inside <noscript> blocks should be excluded from inline CSS volume
• Base64-encoded images (src="data:image/...") bypass network loading but increase HTML size — flag as ⚠️ WARN if total base64 content exceeds 10KB
• SVG images (<img src="*.svg">) do not need WebP/AVIF conversion — exclude from image format checks
• Next.js <Image> component detection: look for /_next/image in src or srcset attributes, or data-nimg attribute
• Dynamically injected scripts (via JS) are not visible in static HTML — note this limitation