CSS Extractor — Help & Documentation

Extract and analyze CSS from web pages to identify performance bottlenecks, unused styles, and optimization opportunities that improve Core Web Vitals.

Overview: Extract and analyze CSS from web pages to identify optimization opportunities, unused styles, and performance improvements.

Features

Extract inline and external CSS
Analyze CSS file sizes and load times
Identify unused CSS rules
Detect CSS validation errors
Performance optimization suggestions
CSS minification analysis

How to Use

Enter page URL — input the URL of the page to analyze.

Choose analysis depth — select inline CSS, external stylesheets, or both.

Run extraction — the tool fetches and processes all CSS resources.

Review recommendations — get actionable optimization tips.

Analysis Results

Performance Metrics

Total CSS file size
Number of CSS requests
Render-blocking resources
Critical CSS identification
Load time impact estimate

Optimization Opportunities

Unused CSS rules
Duplicate selectors
Inefficient selectors
Missing vendor prefixes
Minification potential

Best Practices

CSS Optimization Tips

Critical CSS: Inline above-the-fold styles to speed up initial render
Lazy Loading: Defer non-critical CSS to reduce render blocking
Minification: Remove whitespace and comments to reduce file size
Compression: Enable gzip or brotli compression on your server
Purging: Remove unused CSS rules — especially important for utility frameworks

Performance Impact

CSS optimization can significantly improve:

Page load speeds
First Contentful Paint (FCP)
Largest Contentful Paint (LCP)
Core Web Vitals scores overall

Integration

Export results for use with:

Build tools (Webpack, Vite, Gulp)
CSS purging tools (PurgeCSS, UnCSS)
Performance monitoring dashboards
Code review processes