Footshop Case Study: 2.5x Faster Loading Speed after a Year and a Half of Collaboration

Footshop, in collaboration with PageSpeed.cz, significantly accelerated its websites over several months, enhancing the user experience.

Curious about how we proceeded and what we achieved together?

Footshop is a prominent brand you can't miss.

Footshop is an e-commerce platform for sneakers and streetwear, operating not only in our country but also in Slovakia, Hungary, Romania, and other Central and Eastern European countries. It focuses on premium and limited products, building a strong community of fans.

Now, let’s explore how we helped Footshop speed up their websites.

First, we wanted to identify which metrics were most important to the client. Our analysis revealed that TTFB (Time to First Byte), CLS (Cumulative Layout Shift), and LCP (Largest Contentful Paint) from the Core Web Vitals set were key metrics.

Optimizing Target Metrics

With well-set analytics and quality data, we began optimizing. Since late 2023, we have gradually focused on individual speed metrics based on their priority:

• Backend response speed (TTFB) and loading speed (LCP) – The Footshop development team focused on server tuning, while we assisted with frontend performance, such as optimizing the transition from client-side rendering cached by Service Workers to server-side rendering.
• Improving interaction response times (INP) – In March 2024, Google introduced the INP metric. The interaction response speed was not ideal, and we began working on the SpeedSprint analysis, resulting in several specific adjustments.
• Tuning unwanted layout shifts (CLS) – The next phase of work at the end of 2024 involved fine-tuning the rendering of certain components and reducing the CLS metric values.

You can see one example of optimization in the image.

Optimizing INP by fine-tuning the performance of variant selection on the product detail page.

Results of Collaboration: Metrics Improved Significantly

We are pleased with the achieved metric changes and, most importantly, the user experience improvements.

After about a year and a half of ongoing collaboration, the following metric improvements were achieved:

• Footshop.cz now has 2.5x better loading speed (LCP) on mobile devices.
• The layout shift metric (CLS) improved by more than 8x.
• Interaction responses (and the INP metric) improved by 30%.

Changes in LCP and CLS metrics since the beginning of collaboration.

What do the people at Footshop say about this?

We enjoy collaborating with Footshop, not only for the brand itself but also for the quality of the entire team and their drive. We are genuinely pleased that the Footshop team rates our collaboration highly.

“A great collaboration that brought a skilled partner (= the PageSpeed.cz team) to our small team. They didn’t just bring know-how but also specific tips for adjustments that can be implemented in parts but have a significant overall effect.”

Jiří Hykel, Frontend Developer

Daniel Urban, CIO of Footshop, adds:

“I appreciate the quick orientation in web performance and clear communication with non-technical people in our collaboration with PageSpeed.cz. The greatest benefit is the unique know-how that would be hard for us to achieve on our own.”

Daniel Urban, CIO of Footshop

Such a successful collaboration on website optimization requires several fulfilled conditions on both sides. Let’s summarize them:

1. The client views speed as a crucial part of the user experience and is willing to invest in it, knowing that the investment will pay off.
2. Quality measurement is set up, and we have sufficient data. (Here, our monitoring and SpeedCurve RUM)
3. Our consultants can actively and intensively communicate with the team, and proposed adjustments receive priority in development plans.
4. The collaboration is not one-time but works long-term, allowing us to avoid regression and continuously educate the client’s team.

We thank Footshop for the fruitful collaboration so far and look forward to its continuation!