Project Overview
One of Japan's established retail chains operating 200+ stores nationwide faced a critical challenge: their 10-year-old on-premise e-commerce platform could no longer keep pace with modern consumer expectations. During peak seasons like New Year sales and Golden Week, the system experienced frequent crashes, causing lost revenue and damaged customer trust. The company turned to BCT Global to execute a full platform migration without disrupting their daily operations — a migration that would ultimately need to handle over ¥5 billion in annual online transactions.
The Challenge
The legacy e-commerce system presented multiple interconnected problems that made migration particularly complex:
- The on-premise system crashed 3-4 times during each peak season (New Year, Golden Week, Christmas), resulting in estimated ¥50M in lost sales per incident
- Page load times averaged 6-8 seconds on mobile devices, leading to a 45% mobile cart abandonment rate — far above the industry average of 30%
- The monolithic architecture made it impossible to update the frontend experience without risking backend stability
- Integration with 200+ physical store POS systems for inventory synchronization required zero-downtime migration
- The existing loyalty point system (with 2M+ registered members) needed seamless migration without any point balance discrepancies
- SEO rankings built over 10 years had to be preserved through the migration — any significant ranking drop would impact organic revenue
Our Solution
BCT Global assembled a lab-style dedicated team of 10 engineers — including 2 frontend specialists (Next.js/React), 3 backend developers, 2 DevOps/cloud engineers, 1 Shopify Plus specialist, 1 QA lead, and 1 bilingual project manager. We adopted a phased migration strategy designed to minimize risk:
- Phase 1 — Architecture & Planning (Months 1-2): Comprehensive audit of the legacy system. Designed a headless commerce architecture: Shopify Plus as the commerce engine with a custom Next.js frontend for maximum performance and SEO control. Selected GCP (Cloud Run + Cloud SQL) for infrastructure, with Terraform for infrastructure-as-code.
- Phase 2 — Core Platform Build (Months 2-6): Built the Next.js storefront with server-side rendering for SEO preservation. Implemented Shopify Plus backend with custom integrations for Japanese payment methods (PayPay, LINE Pay, convenience store payments). Developed real-time inventory sync between Shopify and 200+ store POS systems.
- Phase 3 — Data Migration & Testing (Months 6-9): Migrated 2M+ customer accounts, loyalty points (with balance verification), 50,000+ product SKUs, and 5 years of order history. Conducted extensive load testing simulating 3x peak season traffic. Implemented comprehensive redirect mapping for 15,000+ URLs to preserve SEO rankings.
- Phase 4 — Cutover & Optimization (Months 9-12): Executed zero-downtime DNS cutover during a low-traffic window. Monitored performance closely for 3 months post-launch. Integrated Datadog for real-time performance monitoring and alerting. Ongoing optimization of Core Web Vitals scores.
System Architecture
Technology Stack
Results & Impact
The impact was immediate and measurable. Mobile page load times dropped from 6-8 seconds to under 2.5 seconds, directly contributing to a 25% increase in conversion rate. The platform handled its first New Year sale season with zero downtime — a first in the company's online history. Annual infrastructure costs decreased by over ¥200M compared to the legacy on-premise system. SEO rankings were preserved across all 15,000+ migrated URLs, with organic traffic actually increasing 12% in the quarter following migration. The loyalty point migration completed with 100% accuracy across 2M+ member accounts.
"The migration was our biggest technology project in a decade, and honestly, we were nervous. BCT Global's lab-style team gave us the dedicated attention this project demanded. They understood that for a Japanese retailer, zero downtime during New Year sales isn't a nice-to-have — it's absolutely critical. The fact that they pulled off a seamless cutover while preserving our SEO rankings was remarkable."
General Manager, EC Division National Japanese Retail Chain — 200+ stores across Japan