Next-Generation Composable Commerce Architecture

The Business Challenge

Lusso Digitale, a premium Italian fashion house with €45M in annual online revenue, was stuck on a monolithic Magento 1 instance. Page load times averaged 4.8 seconds, mobile conversion was 40% below industry benchmarks, and their marketing team waited 2-3 weeks for simple homepage changes. They needed a modern, fast, and flexible platform — yesterday.

Architectural Decision: Composable Commerce

Rather than migrating to another monolith (Shopify Plus, Salesforce Commerce Cloud), we advocated for a composable commerce approach — best-of-breed services connected via APIs.

1. Storefront: Next.js + Vercel Edge

Next.js 15 App Router with React Server Components for instant page loads.
Static generation for product catalog pages (ISR with 60s revalidation).
Edge middleware for geo-based pricing (EUR/GBP/CHF) and A/B test bucketing.
Core Web Vitals: LCP < 1.2s, CLS < 0.05, INP < 120ms.

2. Commerce Engine: Medusa.js

Open-source Medusa.js as the headless commerce backend.
Custom plugins for Italian tax compliance (split-payment IVA, electronic invoicing via SDI).
Multi-warehouse inventory management with real-time stock sync across 3 physical locations and online.

3. AI Personalization Engine

Real-time behavioral tracking via a custom event stream (Kafka → ClickHouse).
Collaborative filtering model (matrix factorization) trained on 18 months of purchase history.
Contextual bandits for homepage hero banners — the system learns which creative performs best for each user segment.
Product recommendations update in < 100ms using a Redis-backed feature store.

4. Content & Merchandising

Sanity CMS for headless content — editorial lookbooks, campaign landing pages, and rich PDPs.
Visual merchandising rules engine: "If user is in segment 'High-Value Returning', show collection X above the fold."

5. Payment & Compliance

Stripe for international payments with 3D Secure 2.0.
Klarna and Scalapay for buy-now-pay-later (critical for Italian market).
PCI DSS Level 1 compliant architecture with tokenized card storage.

Technology Stack

Frontend: Next.js 15, React Server Components, Tailwind CSS, Framer Motion
Commerce: Medusa.js, Stripe, Klarna, Scalapay
CMS: Sanity.io
AI/ML: Python, Scikit-learn, ClickHouse, Redis, Kafka
Infrastructure: Vercel (Edge), AWS (backend), Cloudflare (CDN)

Business Results (First 6 Months)

+127% mobile conversion rate (from 1.1% to 2.5%).
Page load: 4.8s → 0.9s (81% improvement).
+34% average order value driven by AI recommendations.
Content publishing time: from 2 weeks to 15 minutes.
€3.2M incremental revenue attributed to personalization engine.