E-commerce Store

Build a production-grade commerce platform with customer accounts, product catalog management, checkout, order processing, inventory tracking, and discounting. Model products, variants, stock movements, carts, orders, payments, refunds, and fulfillment states explicitly. Enforce role-based separation between shoppers, support agents, and operations staff. Include idempotent order and payment handling, safeguards against overselling, observability for checkout and fulfillment failures, audit logs for price and inventory changes, secure handling of customer and payment-adjacent data, and a rollout strategy for schema changes that preserves historical order records.