Case Study: deNatura.cz & Shoptet - Green Core Web Vitals and a 17% increase in Google traffic

Through successful collaboration, PageSpeed.ONE improved a client's e-shop speed, boosting Google traffic.

Significant improvements in Core Web Vitals increased deNatura.cz's Google search traffic by 17%.

Discover the story behind this successful speed optimization.

deNatura.cz Website Optimization

The client from deNatura.cz approached us with issues like layout shifts (CLS) and slow interaction response (INP).

Google evaluates SEO and PPC based on the worst speed metrics. At that time, deNatura.cz received a red rating on mobile, affecting its ranking.

The site runs on Shoptet, known for good default speed. PageSpeed.ONE investigated the root causes.

Developers often use JavaScript for design changes, causing layout shifts.

What did we adjust? Here are some key optimizations from two SpeedSprint analyses we prepared:

1. Fixed JavaScript-induced design changes.
2. Reserved space for images to prevent layout shifts.
3. Adjusted carousel appearance before JavaScript initialization.
4. Handled code causing freezes more efficiently.
5. Optimized simultaneous JavaScript operations.

Based on experience with other Shoptet sites, we concluded that improving interaction response (INP) required platform-level changes.

Shoptet Platform Optimization

PageSpeed.ONE's mission is to enhance web experiences through speed optimization. Collaboration is key.

Shoptet hosts over 40,000 e-shops, and we were pleased to assist their developers in optimizing interaction response speed.

Our focus included optimizing long JS tasks from cookie banners and improving lazy loading for images.

The result was green Core Web Vitals for deNatura.cz and thousands of other Shoptet sites, enhancing SEO and PPC ratings on Google.

Improved interaction response (INP) after joint optimization by PageSpeed.ONE and Shoptet.

Thanks to the Shoptet team for excellent collaboration, which they also appreciated:

“We highly recommend working with PageSpeed.ONE. Their expert approach, quick communication, and actionable suggestions significantly improved the performance of thousands of our e-shops. The optimization went smoothly, and the results speak for themselves.”

Denis Chripák, Engineering Team Lead at Shoptet

Optimization Results: Green Core Web Vitals and 17.3% Higher Google Traffic

After all optimizations, deNatura's website speed is excellent.

Metrics before and after optimization.

Core Web Vitals are green and significantly improved. This could impact the business, right?

Thanks to deNatura.cz analyst Milan Merglevský, we see the impact in Google Search Console data:

1. The first positive results came from optimizing Core Web Vitals on deNatura (see point 1 below).
2. INP optimization on Shoptet's side and green Core Web Vitals on deNatura (point 2 below) significantly improved average position, clicks, and impressions on Google search.
3. Post-implementation (November–December 2024) saw a 17.3% increase in sessions compared to the modeled scenario.

Image from Milan Merglevský's analysis showing the impact on organic Google search traffic.

Methodology Notes:

• Google Search Console data is adjusted to exclude brand search queries, removing brand campaign effects.
• Core Updates occurred on August 26, 2025, and December 11, 2025.
• The effect of the second change is statistically significant (p < 0.001).
• The analysis model uses historical data from January to October 2024 as a training sample, considering other marketing channels and Czech public holidays.

Thanks to everyone involved in this complex yet successful collaboration, both at deNatura and Shoptet.

“PageSpeed.ONE experts continually impress me with their advancements. The current collaboration with deNatura.cz is fantastic, and I'm not exaggerating. The team found solutions to previously unsolvable issues, resulting in a visually rich e-shop that runs at lightning speed. Thank you!”

Jan Kvasnička, co-owner of deNatura.cz, UX designer, and CRO specialist