Blog.

landing page speed vitals

Cover Image for landing page speed vitals
SDX VISION
SDX VISION

Landing page speed directly impacts conversions, user experience, and SEO rankings. This guide will teach you how to optimize your landing pages for Core Web Vitals and achieve fast load times.

What are Core Web Vitals?

Core Web Vitals are Google's metrics for measuring user experience:

1. Largest Contentful Paint (LCP)

Target: < 2.5 seconds Measures: How fast main content loads

2. First Input Delay (FID) / Interaction to Next Paint (INP)

Target: < 100ms (FID) or < 200ms (INP) Measures: How quickly page responds to user interaction

3. Cumulative Layout Shift (CLS)

Target: < 0.1 Measures: Visual stability during page load

Why Speed Matters

Impact on Conversions:

  • 1 second delay = 7% conversion drop
  • 3 second delay = 40% bounce rate increase
  • Mobile users expect < 3 second load times

SEO Impact:

  • Core Web Vitals are ranking factors
  • Google prioritizes fast pages
  • Better user experience = better rankings

Optimizing Largest Contentful Paint (LCP)

What Affects LCP:

  • Server response time
  • Render-blocking resources
  • Image loading
  • Web font loading

Optimization Strategies:

1. Optimize Server Response Time:

  • Use fast hosting (CDN)
  • Enable server-side caching
  • Optimize database queries
  • Use efficient server setup

2. Minimize Render-Blocking Resources:

<!-- Defer non-critical CSS -->
<link rel="preload" href="styles.css" as="style" onload="this.onload=null;this.rel='stylesheet'">

<!-- Defer JavaScript -->
<script src="script.js" defer></script>

3. Optimize Images:

  • Use WebP format
  • Implement lazy loading
  • Compress images
  • Use appropriate sizes
  • Add width/height attributes

4. Preload Key Resources:

<link rel="preload" href="hero-image.jpg" as="image">
<link rel="preload" href="font.woff2" as="font" type="font/woff2" crossorigin>

Optimizing First Input Delay (FID) / Interaction to Next Paint (INP)

What Affects FID/INP:

  • JavaScript execution time
  • Main thread blocking
  • Event handler complexity
  • Third-party scripts

Optimization Strategies:

1. Reduce JavaScript Execution:

  • Minimize JavaScript
  • Code splitting
  • Remove unused code
  • Defer non-critical scripts

2. Optimize Event Handlers:

// Use passive event listeners
element.addEventListener('scroll', handler, { passive: true });

// Debounce/throttle handlers
const debouncedHandler = debounce(handler, 100);

3. Use Web Workers:

// Offload heavy processing
const worker = new Worker('worker.js');
worker.postMessage(data);

4. Minimize Third-Party Scripts:

  • Load asynchronously
  • Use iframe for heavy scripts
  • Defer non-critical scripts
  • Consider alternatives

Optimizing Cumulative Layout Shift (CLS)

What Causes CLS:

  • Images without dimensions
  • Ads/embeds without space
  • Web fonts causing FOIT/FOUT
  • Dynamically injected content

Optimization Strategies:

1. Set Image Dimensions:

<img src="image.jpg" width="800" height="600" alt="Description">

2. Reserve Space for Ads/Embeds:

<div style="min-height: 250px;">
  <!-- Ad will load here -->
</div>

3. Preload Web Fonts:

<link rel="preload" href="font.woff2" as="font" type="font/woff2" crossorigin>

4. Use Font Display:

@font-face {
  font-family: 'MyFont';
  src: url('font.woff2') format('woff2');
  font-display: swap; /* or optional, fallback */
}

Comprehensive Speed Optimization

1. Image Optimization

Best Practices:

  • Use modern formats (WebP, AVIF)
  • Implement responsive images
  • Lazy load below-fold images
  • Compress images (TinyPNG, ImageOptim)
  • Use CDN for images

Implementation:

<picture>
  <source srcset="image.avif" type="image/avif">
  <source srcset="image.webp" type="image/webp">
  <img src="image.jpg" alt="Description" loading="lazy">
</picture>

2. CSS Optimization

Strategies:

  • Minify CSS
  • Remove unused CSS
  • Critical CSS inline
  • Defer non-critical CSS
  • Use CSS containment

Critical CSS:

<style>
  /* Above-the-fold styles inline */
</style>
<link rel="stylesheet" href="non-critical.css" media="print" onload="this.media='all'">

3. JavaScript Optimization

Strategies:

  • Minify and compress
  • Code splitting
  • Tree shaking
  • Lazy load modules
  • Use modern JavaScript

Code Splitting:

// Dynamic import
const module = await import('./module.js');

4. Caching Strategy

Browser Caching:

# Nginx example
location ~* \.(jpg|jpeg|png|gif|ico|css|js)$ {
    expires 1y;
    add_header Cache-Control "public, immutable";
}

Service Workers:

// Cache static assets
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open('v1').then((cache) => {
      return cache.addAll([
        '/',
        '/styles.css',
        '/script.js'
      ]);
    })
  );
});

5. CDN Implementation

Benefits:

  • Faster content delivery
  • Reduced server load
  • Global distribution
  • Better performance

Popular CDNs:

  • Cloudflare
  • Amazon CloudFront
  • Fastly
  • KeyCDN

Mobile Optimization

Mobile-Specific Optimizations:

1. Responsive Images:

<img srcset="small.jpg 480w, medium.jpg 768w, large.jpg 1200w"
     sizes="(max-width: 480px) 100vw, (max-width: 768px) 50vw, 33vw"
     src="medium.jpg" alt="Description">

2. Touch Optimization:

  • Larger tap targets (44x44px minimum)
  • Adequate spacing
  • Fast touch response

3. Mobile-First Design:

  • Mobile-first CSS
  • Progressive enhancement
  • Touch-friendly UI

Testing and Monitoring

Tools:

1. Google PageSpeed Insights:

  • Core Web Vitals scores
  • Optimization suggestions
  • Field and lab data

2. Chrome DevTools:

  • Performance profiling
  • Network analysis
  • Lighthouse audits

3. WebPageTest:

  • Detailed performance analysis
  • Waterfall charts
  • Multiple locations

4. Real User Monitoring:

  • Actual user metrics
  • Real-world performance
  • Continuous monitoring

Monitoring Setup:

1. Google Search Console:

  • Core Web Vitals report
  • Field data
  • Issue identification

2. Analytics:

  • Page load times
  • Bounce rates
  • User behavior

3. Custom Monitoring:

  • Performance API
  • Real User Monitoring
  • Custom dashboards

Optimization Checklist

  • [ ] LCP < 2.5 seconds
  • [ ] FID/INP < 100ms/200ms
  • [ ] CLS < 0.1
  • [ ] Images optimized (WebP, compressed)
  • [ ] CSS minified and optimized
  • [ ] JavaScript minimized and deferred
  • [ ] Caching implemented
  • [ ] CDN configured
  • [ ] Mobile optimized
  • [ ] Fonts optimized
  • [ ] Third-party scripts optimized
  • [ ] Server response time < 200ms

Common Issues and Solutions

Issue 1: Slow LCP

Solutions:

  • Optimize server response
  • Preload key resources
  • Optimize images
  • Minimize render-blocking

Issue 2: High FID/INP

Solutions:

  • Reduce JavaScript execution
  • Optimize event handlers
  • Use web workers
  • Minimize third-party scripts

Issue 3: High CLS

Solutions:

  • Set image dimensions
  • Reserve space for dynamic content
  • Optimize fonts
  • Avoid layout shifts

Best Practices

  1. Measure First: Use tools to identify issues
  2. Optimize Critical Path: Focus on above-the-fold
  3. Progressive Enhancement: Build from mobile up
  4. Regular Testing: Monitor continuously
  5. Iterate: Continuous improvement

Next Steps

  1. Audit Current Performance: Use PageSpeed Insights
  2. Identify Issues: Focus on Core Web Vitals
  3. Implement Optimizations: Follow this guide
  4. Test Changes: Verify improvements
  5. Monitor Continuously: Track performance

Thanks for reading the blog. If you want more help, do contact us at https://sdx.vision