A detailed technical case study showing how I improved Core Web Vitals scores from 45 to 95+ using advanced optimization techniques, resulting in 300% traffic increase and improved user experience.
When I inherited a client’s e-commerce site with Core Web Vitals scores in the red zone (45/100), I knew this wasn’t just a performance issue-it was a business problem. Poor Core Web Vitals directly impact search rankings, user experience, and conversion rates.
This case study details the technical approach I used to transform their performance from failing to excellent, achieving sub-second load times and a 300% increase in organic traffic.
The client’s website was experiencing:
The site was built on WordPress with a heavy theme, multiple plugins, and unoptimized images. Users were abandoning the site before it fully loaded, and Google was penalizing it in search results.
I used a comprehensive toolkit to identify bottlenecks:
JavaScript Execution:
Image Optimization:
CSS Optimization:
Server Performance:
Critical CSS Extraction:
/* Extracted critical above-the-fold CSS */
.hero-section {
background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
min-height: 100vh;
display: flex;
align-items: center;
}
/* Non-critical CSS loaded asynchronously */JavaScript Optimization:
async and defer attributes strategicallyWebP Implementation:
<picture>
<source srcset="hero-image.webp" type="image/webp">
<img src="hero-image.jpg" alt="Hero image" loading="lazy">
</picture>Responsive Images:
<img src="product-small.jpg"
srcset="product-small.jpg 480w,
product-medium.jpg 800w,
product-large.jpg 1200w"
sizes="(max-width: 480px) 100vw,
(max-width: 800px) 50vw,
25vw"
alt="Product image">CDN Configuration:
Caching Strategy:
# .htaccess optimization
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType text/css "access plus 1 year"
ExpiresByType application/javascript "access plus 1 year"
ExpiresByType image/png "access plus 1 year"
ExpiresByType image/jpg "access plus 1 year"
ExpiresByType image/webp "access plus 1 year"
</IfModule>Before Optimization:
Search Performance:
User Experience:
Technical Metrics:
Performance optimization should be integrated into the development process from day one, not treated as a post-launch fix.
You can’t improve what you don’t measure. Comprehensive monitoring is essential for identifying bottlenecks and tracking improvements.
Technical optimizations directly impact business metrics. The 300% traffic increase wasn’t just from better rankings—it was from users actually engaging with the faster site.
Performance optimization is ongoing. Regular monitoring and incremental improvements are more effective than one-time fixes.
// Critical CSS extraction process
const critical = require('critical');
critical.generate({
inline: true,
src: 'index.html',
css: ['styles/main.css'],
width: 1300,
height: 900,
minify: true
});// Code splitting implementation
const ProductPage = lazy(() => import('./ProductPage'));
const CheckoutPage = lazy(() => import('./CheckoutPage'));
// Lazy loading with Suspense
<Suspense fallback={<LoadingSpinner />}>
<ProductPage />
</Suspense>// Automated image optimization
const sharp = require('sharp');
async function optimizeImage(inputPath, outputPath, width, quality) {
await sharp(inputPath)
.resize(width)
.jpeg({ quality })
.webp({ quality })
.toFile(outputPath);
}This case study demonstrates that Core Web Vitals optimization isn’t just about technical metrics—it’s about creating better user experiences that drive business results. The 300% increase in organic traffic and 28% improvement in conversion rates prove that performance optimization is a critical business strategy.
The key to success was taking a systematic, data-driven approach to identifying bottlenecks, implementing targeted optimizations, and continuously monitoring results. This methodology can be applied to any website, regardless of platform or complexity.
Key Takeaways:
This approach has become my standard methodology for all performance optimization projects, consistently delivering measurable improvements in both technical metrics and business results.
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I’m happy to share how I’d approach it or jump in hands‑on to help.
