I built a custom Shopify Plus store for Gymshark from scratch to handle extreme traffic and millions of users. Using Liquid, JS, and Tailwind, I delivered a mobile-first UI with CRO features like AJAX carts and personalized feeds. I also implemented Shopify Scripts and ERP/CRM integrations to manage global scale. This overhaul boosted checkout completion by 15% and ensured 100% stability during peak sales. Looking for custom theme development and CRO that drives revenue? Message me to get started.