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

During a successful multi-party collaboration, we at PageSpeed.ONE improved the client's e-shop speed, increasing Google traffic.

Significant improvements in Core Web Vitals metrics brought deNatura.cz a 17% increase in Google search traffic.

Join us to explore the story of this highly successful speed optimization.

Optimization of deNatura.cz

The client from deNatura.cz approached us with issues related to unwanted layout shifts (CLS), later compounded by slow interaction response (INP).

Google evaluates websites for SEO and PPC based on the worst color of certain speed metrics. At that time, deNatura.cz received a red rating on mobile, resulting in a poorer starting position.

The site runs on the Shoptet platform, known for its good speed in default settings. At PageSpeed.ONE, we began identifying the root causes of the issues.

Developers often modify the site's appearance using JavaScript during design changes, causing unpleasant layout shifts.

What did we adjust at this stage? Here are some sample optimizations from two SpeedSprint analyses we prepared for the client:

1. We fixed appearance changes made with JavaScript.
2. We reserved space for images to prevent layout shifts.
3. We altered carousel appearances on the homepage before JavaScript initialization.
4. We handled code causing freezes more carefully.
5. We optimized the number of operations triggered simultaneously by JavaScript.

Gradually, thanks to experience from optimizing other Shoptet-based sites, we concluded that to improve the interaction response speed metric (INP), we needed to go beyond the platform itself.

Optimization of the Shoptet platform

PageSpeed.ONE's mission is to enhance web experiences through speed optimization. Ideal collaboration has a broad reach.

Shoptet operates over 40,000 e-shops, and we're pleased to have helped this largest Czech e-shop platform's development team optimize interaction response speed.

What did we work on in this case? For example, optimizing long JS tasks generated by the cookie banner or improving lazy image loading solutions.

The result was green Core Web Vitals metrics not only for deNatura.cz but also for thousands of other Shoptet sites. This also led to a bonus in the form of better ratings for SEO or PPC on Google.

Improvement in interaction response (INP metric) after joint optimization by PageSpeed.ONE and Shoptet.

We thank the Shoptet team for excellent collaboration and are glad they feel the same:

“We highly recommend working with PageSpeed.ONE. We appreciate their expert approach, quick communication, and specific proposals that had a real impact on improving 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 a 17.3% increase in Google traffic

After all optimizations, deNatura is now doing very well in terms of website speed.

Status of metrics before and after optimization.

Core Web Vitals metrics are green and significantly better. Could this impact the business side of the website?

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

1. The first visible positive results came from optimizing Core Web Vitals metrics on deNatura's site (see point 1 in the image below).
2. INP optimization on Shoptet's side and green Core Web Vitals on deNatura's site (point 2 in the image below) had a significant positive impact on improving average position, clicks, and impressions in Google search.
3. In the post-implementation period (November–December 2024), there was a total session increase of +17.3% compared to the modeled scenario.

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

Methodology notes:

• Google Search Console data is cleaned of brand search queries to remove the effect of brand campaigns.
• The effect of the second change is statistically highly significant (p < 0.001).
• The model in the analysis uses historical data from January to October 2024 as a training sample and considers the effects of other marketing channels and Czech public holidays.

We thank everyone involved in this complex but very successful collaboration, both on the deNatura side and the Shoptet platform side.

“The experts at PageSpeed.ONE constantly surprise me with how they push their outputs and possibilities. The current collaboration with deNatura.cz is amazing, and I'm not exaggerating. The team found solutions to issues that couldn't be solved before. Thanks to this, we have an e-shop full of important visual content that runs super fast. Thank you very much!”

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