38% conversion uplift on a headless commerce rebuild
Engagement
14 weeks
Team
1 tech lead, 3 engineers, 1 designer, 1 QA
Industry
E-commerce & Retail
Stage
Series C
The numbers that mattered to the client.
What we walked into.
The client's Magento storefront was the conversion bottleneck. LCP of 4.2s on mobile. Checkout completion under 60%. Trustpilot rating at 3.4★ driven mostly by site-performance complaints. The team was spending 40% of engineering time on Magento maintenance instead of feature work.
The brief was clear: rebuild the storefront, keep the Shopify backend (already integrated with the warehouse and finance), and ship in one quarter.
What we built.
We rebuilt the storefront on Next.js 16 with Shopify as the commerce backend (headless via Storefront API), Stripe for payments, and Algolia for search. The design system was rebuilt from scratch — 38 components, full token set, accessibility AA.
Performance was the primary non-functional requirement. We set budgets: LCP under 1s, JS bundle under 150kb initial, image weight under 300kb on mobile. Every PR that breached a budget failed CI. The 0.8s LCP is the result of those budgets, not a tuning exercise at the end.
We ran a 5-day design sprint in week 2 to test the new checkout flow with 8 users. The sprint killed one bad assumption (a 'one-page checkout' that confused users) and saved 4 weeks of engineering.
Tech stack
What changed for the client.
- Conversion uplift 38% (measured over 90 days post-launch vs 90 days pre-launch)
- Mobile LCP 0.8s (was 4.2s) — Google Core Web Vitals all green
- Trustpilot rating 4.8★ within 60 days of launch
- Cart abandonment down 27%
- Engineering time on feature work up from 60% to 92% (no Magento maintenance)
“They shipped our headless rebuild in 14 weeks. 38% conversion uplift, 0.8s LCP, 4.8★ on Trustpilot. We've stopped firefighting Magento and started shipping features.”
VP E-commerce
Series C D2C brand
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