Google has made it clear: Performance is a ranking factor. Online shops with poor Core Web Vitals are pushed down in search results. At the same time, industry studies show: Longer loading times can noticeably affect conversion rates. In this article, you'll learn which metrics really matter and why a PageSpeed score of 100 is achievable.
What Are Core Web Vitals?
Core Web Vitals are Google's official metrics for user experience on websites. They measure three critical aspects of page experience:
LCP (Largest Contentful Paint)
How quickly is the largest visible content loaded? Target: under 2.5 seconds
INP (Interaction to Next Paint)
How quickly does the page respond to user interactions? Target: under 200ms
CLS (Cumulative Layout Shift)
How stable is the layout during loading? Target: under 0.1
These metrics are measured directly by Google - not in the lab, but from real users (field data). A poor score in Google Search Console has direct impact on your SEO rankings.
Why Performance Is Critical for E-Commerce
The effects of poor performance are noticeable for online shops. Various industry studies show a clear trend:
| Load Time | Impact on Conversion | Bounce Rate |
|---|---|---|
| 1-2 seconds | Optimal | Low |
| 3 seconds | Noticeably reduced | Increased |
| 5 seconds | Significantly reduced | Highly increased |
| 10+ seconds | Critically reduced | Very high |
The specific impact of loading times on conversion and bounce rates varies by industry, target audience, and study. The trends shown here are based on various e-commerce studies (including Google, Akamai) and serve as guidance.
Improving load time can have a noticeable revenue impact depending on the shop and starting situation - without additional marketing budget.
The Most Common Performance Killers
When analyzing online shops, we always find the same problems. These performance killers are often easy to fix - if you know where to look:
- Unoptimized images: The biggest problem. Full-resolution images without WebP/AVIF
- Render-blocking resources: CSS and JavaScript blocking the first paint
- No lazy loading: All images loaded immediately, even below the fold
- Missing browser cache: Assets reloaded on every visit
- Slow server: Time to First Byte (TTFB) over 600ms
Many shop operators install performance plugins and think the problem is solved. Without proper configuration and systematic optimization, these tools do little.
Optimizing LCP: The Biggest Lever
Largest Contentful Paint (LCP) has the biggest impact on perceived load time. Typically, LCP is the hero image or a large product image. To optimize LCP, several factors must work together:
- Hero image as WebP/AVIF with optimal compression
- Preload for the LCP element
- Critical CSS inline in head
- No render-blocking scripts before LCP
- Fast server response (TTFB under 200ms)
Technical implementation requires deep adjustments to the shop system. From server configuration to build system to template - all components must be coordinated.
INP: The New Metric for Interactivity
Interaction to Next Paint (INP) replaced First Input Delay (FID) as a Core Web Vital in 2024. INP measures how quickly the page responds to all user interactions - not just the first one.
For online shops, INP is particularly critical: Filters, product configurators, add-to-cart buttons - all these interactions must respond immediately. An INP over 200ms feels sluggish to users and leads to abandonment.
The most common INP problems arise from too much JavaScript on the main thread. Code-splitting, lazy loading of non-critical JS, and web workers can help.
CLS: Ensuring Layout Stability
Cumulative Layout Shift (CLS) measures how much the layout shifts during loading. Nothing is more frustrating for users than when the button they were about to click suddenly jumps down.
Typical CLS causes in online shops:
- Images without defined sizes
- Late-loading web fonts (FOUT)
- Dynamically inserted ad banners
- Lazy-loaded content without placeholders
- Cookie banners without reserved space
Image Optimization: The Biggest Quick Win
Images make up 60-80% of data volume in most online shops. Professional image optimization can often reduce load time by 50% or more.
| Format | File Size (same quality) | Browser Support |
|---|---|---|
| JPEG | 100 KB | 100% |
| WebP | 65 KB (-35%) | 97%+ |
| AVIF | 45 KB (-55%) | 90%+ |
Converting to modern image formats requires adjustments to the CMS and often the build process. Responsive images with srcset and the picture element for fallbacks are standard for professional shops.
Server Performance and Hosting
The best frontend optimization does little if the server responds slowly. Time to First Byte (TTFB) should be under 200ms. With complex shop systems and many products, this is hardly achievable without professional hosting and caching.
- HTTP/2 or HTTP/3 for parallel loading
- CDN for static assets
- Redis/Varnish for dynamic caching
- PHP OPcache optimally configured
- Database optimization for fast queries
Why PageSpeed Score 100 Is Achievable
Many shop operators consider PageSpeed score 100 difficult to achieve. Our experience shows: For most projects, a very high score is achievable - even for complex online shops with thousands of products. However, it requires a systematic approach.
The PageSpeed score can fluctuate slightly between measurements - this is normal and due to varying server response times and network conditions. With certain technical foundations (e.g., specific external integrations like tracking pixels or complex shop systems), score 100 is not always achievable. In these cases, we aim for the best possible value.
We systematically analyze every aspect of performance: Server, caching, assets, JavaScript, CSS, images. With optimal configuration of all components, a very high score can be achieved.
The path to optimal performance is individual for each shop. Some shops mainly need image optimization, others have JavaScript issues, still others suffer from slow servers. A professional analysis identifies the biggest levers.
Core Web Vitals are an official ranking factor at Google. Shops with poor values are ranked lower than fast competitors with equal relevance.
Google Search Console shows field data from real users. For lab data, use Lighthouse in Chrome DevTools or PageSpeed Insights.
Depending on the starting situation, between 2 and 8 weeks. The biggest improvements are often achieved in the first days, score 100 requires fine-tuning.
No, in most cases existing shops like Shopware or WooCommerce can be made fast through targeted optimization.
Better SEO rankings, higher conversion rates, lower bounce rates, and happier customers. The investment pays off multiple times.
PageSpeed Analysis for Your Shop
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