Microservices Architecture for UK RetailTech — UK Consumer Rights Act Built In

Retail Microservices — Commerce-Specific Domains

UK RetailTech microservices decompose by retail commerce domains. Recommended domain boundaries: (1) Product Catalogue Service (product data, pricing, inventory — feeds storefront and OMS), (2) Order Management Service (OMS — order lifecycle: placed → confirmed → picking → dispatched → delivered → returned), (3) Customer Service (customer profile, order history, loyalty balance — GDPR data owner), (4) Payment Service (wraps Stripe/GoCardless — PCI-DSS scope isolation), (5) Fulfilment Service (carrier selection, label generation, tracking webhooks), (6) Promotions Service (discount codes, flash sales, tier pricing — peak trading isolation), (7) Notifications Service (order confirmation, dispatch, delivery — GOV.UK Notify), (8) Inventory Service (real-time stock — oversell prevention, multi-location allocation).

UK Consumer Rights Act Returns in Microservices

Consumer Rights Act returns microservices design: customer initiates return (Order Management Service) → eligibility check (14-day right to withdraw — CRA 2015 automatic eligibility for consumer goods) → return label issued (Fulfilment Service — Royal Mail returns label) → return received confirmation (warehouse scan → Fulfilment Service webhook → Order Management Service) → refund initiated (Payment Service — Stripe refund or GoCardless reversal within 14 days — CRA requirement) → customer notified (Notifications Service — GOV.UK Notify). Event-driven: every step publishes a domain event to SNS → other services consume. CRA compliance: refund issued within 14 days of receiving the returned goods — automated timer from return received event, Payment Service escalation if > 12 days.

Peak Trading Isolation in Retail Microservices

UK Black Friday peak trading: 10× normal traffic. Microservices isolation: Promotions Service (flash sale logic — most complex at peak) deployed independently with higher ECS task count during peak. Independent scaling: Promotions Service scales to 50 tasks (Black Friday) while Order Management Service scales to 20 (proportional to order volume). Circuit breakers: if Promotions Service degrades (flash sale validation slow) → Product Catalogue Service uses cached price (no promotion) rather than waiting — prevents peak trading cascade failure. Promotions Service pre-warming: 2 hours before Black Friday start → 30 ECS tasks already warm (no cold start during first wave). Pre-peak load test: JMeter / k6 load test simulating 10× traffic run 2 weeks before Black Friday.

Shopify Headless + Microservices BFF Pattern

Shopify headless (Shopify Storefront API) + custom microservices: Shopify handles checkout and payments (PCI-DSS SAQ-A), custom microservices handle everything else. BFF (Backend For Frontend): Next.js App Router calls BFF (Node.js API Gateway) which aggregates from: (1) Shopify Storefront API (product data, cart), (2) Customer Service (loyalty balance, order history), (3) Promotions Service (available promotions for this customer tier), (4) Inventory Service (real-time stock levels). BFF benefits: storefront makes one API call (not 4 separate calls to different services) — response assembled server-side, one HTTP round trip for client. Cache: BFF Redis cache for product catalogue and promotions data (TTL 60 seconds during Black Friday — stale pricing acceptable for non-personalised promotions).

UK Consumer Rights Act

PECR

UK GDPR

PCI-DSS SAQ-A

WCAG 2.1 AA

Cyber Essentials