Integralmédica / Darkness

Integralmédica and Darkness are supplement brands sharing one Shopify admin and one repository: two headless storefronts with a cart shared between them. I joined halfway through development and took over as tech lead. From then on, every feature and every decision went through me, and I built most of the features myself.

The shared cart was the known part. What made this project hard was something else: the sheer volume of business rules that simply don't exist in off-the-shelf Shopify. Supplements are a category with heavy promotional mechanics, and the client's requirements ran straight into the limits of the native checkout and account area. The recurring question wasn't “how do I configure this?” but “this doesn't exist, so what do we build?”

• Promotional mechanics as Shopify FunctionsDiscount and promotion rules the platform doesn't ship natively, implemented as Functions running on Shopify's side instead of as hacks in the front-end.
• Purpose-built custom appsSeveral in-house apps, with their own interfaces, covering what no marketplace app solved.
• Employee discount with an inverted calculationAn app with its own interface where the discount doesn't come off the selling price: the math starts from the compare-at price and takes 50% off that. A rule that's simple to state and impossible to configure in an off-the-shelf app.
• Account area rebuilt from scratchShopify's native account area was dropped and rebuilt end to end: per-brand identity, control over how orders are displayed and filtered, and tabs the native one can't have, like “My benefits,” wired into the loyalty program.
• Checkout blocksCheckout extensions that bring information and features into the most sensitive step of the purchase.
• Reporting and data integrationsA range of reports, CRM integrations and third-party script integrations, with a significant amount of data flowing out of the store.
• Brand sections and landing pagesDeeply customizable sections and pages, so the content team can work without waiting on a deploy.

• The native account doesn't survive two brandsShopify gives you one account area per admin — and here one admin serves two brands. In practice, that means identical styling for Integralmédica and Darkness, without even a per-brand logo: half the customers would log in and see the other brand. On top of that, there's no control over how orders are displayed or filtered, and no way to add a tab, and we needed “My benefits,” wired into the loyalty program. Rebuilding the whole account area was cheaper than fighting all three limits at once.
• A custom app instead of a marketplace subscriptionThe promotion the client wanted doesn't exist natively. The obvious path was to subscribe to an App Store app and move on, adding a permanent monthly line to their budget. I built a custom app instead: once it's installed and the gift products are configured, it needs no recurring maintenance and has no subscription. I traded a permanent monthly cost for a one-time build cost, and that only makes sense because the rule is stable. If the mechanic changed every campaign, the off-the-shelf app would win.
• Promotion rules on Shopify, not in the front-endThe promotional mechanics were implemented as Shopify Functions, on the platform side. A discount that only exists in the front-end is a discount that vanishes at checkout — and checkout is where the customer decides whether they trust the store.

Integralmédica and Darkness are in production. Both storefronts are live if you want to inspect them.