Headless E-Commerce Platform Rebuild
2.1× conversion increase and 38% faster page load after headless rebuild.
About the client
UK Fashion Retailer (NDA)
United Kingdom
A fast-growing UK fashion retailer with 250,000 active customers and £8M annual online revenue. Their Magento 1 store was technically end-of-life, lacked mobile optimisation, and required 3 weeks of developer time for any significant feature change — making it impossible to compete with agile DTC competitors.
Technologies used
Results at a glance
2.1×
Conversion increase
38%
Faster page load
1.2s
Mobile FCP (was 5.8s)
3 wk
Feature delivery vs. 3 months
In the first full trading quarter after launch, the retailer saw their highest-ever online revenue — up 67% YoY, against a market that grew 8%. The engineering team now ships features in 3 weeks that previously took 3 months.
Overview
The context
The era of the monolithic e-commerce platform is over for growth-focused retailers. The brands winning in digital commerce today have composable architectures — where the frontend, commerce engine, CMS, and analytics are decoupled services that can each be updated independently and scaled to demand.
We brought this architecture to a retailer who had been locked in a Magento 1 monolith for 5 years — designing a phased migration that kept the existing store live throughout, with zero revenue downtime during the transition.
The challenge
The Challenge
The existing Magento 1 store had a 5.8-second mobile First Contentful Paint — in an era where Google's research shows a 1-second delay reduces conversions by 7%. Mobile accounted for 72% of their traffic but only 44% of revenue, a clear sign of a performance-driven conversion gap.
The product and marketing teams had 40+ features in a backlog that couldn't be shipped because every change required the same two developers who understood the legacy codebase — creating a dependency bottleneck that had persisted for 18 months.
Our solution
What We Built
A Next.js App Router storefront with Shopify as the commerce backend — giving the client a battle-tested inventory and checkout engine while freeing the frontend to be built for performance. The storefront implements Incremental Static Regeneration for category and product pages, with edge-cached personalisation for logged-in users.
A visual merchandising layer connected to their analytics data auto-ranks products by conversion-per-impression within each category, with A/B test infrastructure so the merchandising team can run experiments without engineering.
- Next.js App Router with ISR for all product and category pages
- Shopify Storefront API as commerce backend
- Algolia-powered search with personalisation
- Analytics-driven auto-merchandising
- Built-in A/B testing infrastructure
- Zero-downtime phased migration from Magento 1
Outcomes
The results
In the first full trading quarter after launch, the retailer saw their highest-ever online revenue — up 67% YoY, against a market that grew 8%. The engineering team now ships features in 3 weeks that previously took 3 months.
2.1×
Conversion increase
38%
Faster page load
1.2s
Mobile FCP (was 5.8s)
3 wk
Feature delivery vs. 3 months
“We'd been on Magento 1 for five years — everyone told us migration was impossible without downtime. Chayaniq proved them wrong and delivered a store that's genuinely better in every measurable way.”
Head of Digital
UK Fashion Retailer
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