Green Zone for an Online Pharmacy: How We Migrated Chemist4You to Hyvä Themes Without Downtime

Chemist4You is a trusted UK online pharmacy that helps thousands of customers every day order medications, healthcare products, and prescription treatments online. It's not a startup finding its footing - it's an established player with a large, loyal customer base and a Trustpilot record most retailers would envy.

But by the time we started working together, the platform behind that reputation hadn't kept pace with the business built on top of it.

The site was still running on an outdated version of Magento, with slow page loads and Magento's default storefront theme, Luma - flexible enough for a generic online store, but not built for a pharmacy's specific compliance and consultation workflows.

To stay ahead in the UK's fast-growing online healthcare market and keep giving customers the experience they'd come to expect, the platform needed more than a patch. It needed a rebuild.

📈 Core Web Vitals moved from failing to passing across LCP, INP, and CLS The entire storefront rebuilt on Hyvä Themes, replacing the legacy Luma frontend Magento core upgraded to 2.4.7-p1, with every third-party module updated alongside it - zero downtime

We could have patched the old theme and moved on - that's usually the faster route.

But a closer look made it clear we'd just be buying time: the technical debt wasn't in the styling, it was baked into the theme's architecture. So we proposed the harder but more durable option: a full rebuild on Hyvä Themes.

That meant:

• Building a new, custom Hyvä theme that kept Chemist4You's visual identity fully intact - this wasn't a redesign, it was a rebuild underneath a familiar face.

• Rebuilding the consultation step engine on Hyvä and AlpineJS, so prescription questionnaires felt fast and native instead of bolted on.

• Rebuilding the frontend on Tailwind CSS for consistency and speed.

• Upgrading the Magento core to 2.4.7-p1 and bringing every critical third-party integration along with it.

Our first instinct, like most teams facing a deadline, was to save time: patch the existing theme instead of rebuilding it. The deeper we got into scoping that work, the less it looked like a shortcut.

The step engine's business logic, validation rules, and UX were wired into the legacy theme in ways a partial refactor wouldn't untangle - we'd have been patching around the same fragile code every time we touched it again.

So we scrapped the shortcut and scoped the full migration instead: Hyvä on the frontend, AlpineJS driving the step engine, and a Magento core upgrade to 2.4.7-p1 running in parallel.

The hardest part wasn't any single piece of that - it was keeping all three moving at once without ever breaking the consultation flow the whole pharmacy's compliance model depends on.

The step engine was built from scratch on AlpineJS: a lightweight, purpose-built consultation flow that plugs directly into Magento's cart logic instead of running alongside it.

Keeping the DOM lean mattered as much as keeping the logic correct - this flow runs before every sensitive purchase, so it had to feel instant, not like a compliance checkpoint bolted onto checkout.

Alongside it, we extensively customized the standard Hyvä templates to support workflows the out-of-the-box theme was never built for.

Technical

• Core Web Vitals: red/amber → green across LCP, INP, and CLS, even under peak traffic

• Magento core: outdated and risky → 2.4.7-p1, with every module upgraded alongside it

• Zero downtime across the entire migration

Business

• Lower long-term hosting and maintenance costs, moving off Magento's traditional Luma theme

• Fewer third-party modules to maintain, less overhead

• A faster, more reliable consultation flow for prescription orders - the part of the business that can least afford friction