How HOLY made one of Germany's largest Shopify shops 47% faster with Speed Kit

Introduction

HOLY was founded in Berlin in 2021 with a simple idea: make soft drinks that people actually feel good about drinking. What started as a powder-based energy drink for the gaming community has grown into a full range of energy, iced tea and hydration products with a large customer base across several European markets — sold direct-to-consumer and, increasingly, on supermarket shelves.

Its shop, de.holy.com, is built on Shopify and is one of the largest Shopify stores in Germany by traffic, with millions of visits every month across a fast-moving catalogue of collections, bundles and product pages. At that scale, load time is not a technical detail but a commercial one: HOLY's audience arrives mostly on mobile, largely from social and creator campaigns, and decides in seconds whether to keep browsing.

To make the shop feel as immediate as the brand, HOLY introduced Speed Kit — with the goal of delivering pages dramatically faster without rebuilding the theme or leaving Shopify.

Challenge

A Shopify storefront gives a fast-moving brand enormous freedom, but the rendering path is largely fixed: the storefront has to be assembled and delivered before a visitor sees a product image or a price, and every app, pixel and personalisation layer added on top competes for the same milliseconds.

For HOLY, that hit exactly the pages that carry the business — the collection pages where visitors browse the range and the product pages where they decide. The team wanted a step change in load times on those surfaces without replatforming, without rebuilding the theme, and without touching the cart, checkout or account flows.

Solution

Speed Kit was installed as a Shopify app on top of the existing storefront — no replatforming, no theme rebuild, no change to the checkout. Instead of assembling each page on request, Speed Kit renders HOLY's collection and product pages in the background and serves visitors the finished view, so content appears without waiting for the full storefront round trip.

On top of that sits predictive preloading: Speed Kit anticipates which page a visitor is most likely to open next and prepares it in advance, separately for mobile and desktop layouts, so the next tap frequently resolves from memory rather than from the network. The order funnel — cart, checkout and account — is deliberately left untouched. The result is a shop that feels immediate on exactly the surfaces where HOLY's mobile-first audience makes its decisions.

Results

Predictive Preloading Coverage

Speed Kit tracked eligible navigations across the accelerated storefront and prepared 84% of next pages before visitors opened them. For 45% of visitors, the next page was already rendered in the background.

Performance Improvements — Largest Contentful Paint

During the PoC phase, Speed Kit roughly halved Largest Contentful Paint across the accelerated pages — most dramatically on the product pages, where the main content now appears more than 700 ms sooner. Across all accelerated pages, median LCP improved by 520 ms.

The gains start at the very first byte: server response time dropped by 80%, or 323 ms, and the first content appeared 41%, or 292 ms, sooner. That is what makes the improvement visible to visitors rather than only to a measurement tool.

Business Impact — PoC Phase

Across all measured sessions, the Speed Kit experience produced a +1.35% relative uplift in conversion rate. The result is statistically significant at the 90% confidence level.

Deeper Engagement

Faster pages also changed how visitors moved through the shop. Page impressions per session rose by 2.32%, rising to 2.71% among non-bounced sessions. Deep engagement — sessions with ten or more page impressions — increased by 3.01%, while the bounce rate fell by 0.28%.

Conclusion

For a brand that lives on speed in every other sense, the shop had to keep up. Speed Kit cut Largest Contentful Paint on the accelerated pages by 520 ms — 47% faster, with product pages 60% quicker — and prepares 84% of follow-up pages before the click, with 45% of visitors receiving a page that was already pre-rendered in the background.

Commercially, the PoC delivered a statistically significant +1.35% relative uplift in conversion rate, alongside measurably deeper engagement. Speed Kit is now live for all traffic on de.holy.com, so every visitor gets the faster experience — and the Shopify setup, theme and checkout stayed exactly as they were.