The E-commerce Scale Challenge
Build a store that handles carts, inventory race conditions, complex pricing, and checkout flows that don't break under load.
Build your unique store
Same e-commerce patterns. Your unique, hilarious product catalog.
The 10-day journey
Each day, a stakeholder email drops with new requirements. Just like real work.
Display products from the API with proper loading and error states.
Build cart architecture with add, remove, update, and quantity handling.
Server vs client carts, session handling, and merge strategies.
Stock levels, availability indicators, and out-of-stock handling.
Base prices, sale prices, and formatted display from server.
Single coupon application, validation UI, and error messages.
Multiple discounts, tiered pricing, bundles. New pricing engine API.
Multi-step form, address/payment sections, and validation.
Success states, order summary, and error recovery patterns.
Performance optimization, loading states, and production deploy.
What you'll actually learn
Not just how to build a cart — but how to build one that doesn't fall apart at scale.
Cart Architecture
Server vs client carts, session persistence, merge strategies, and why 'add to cart' is harder than it looks.
Inventory Sync
Optimistic updates, reservation systems, race condition handling, and 'last one in stock' patterns.
Pricing Systems
Tiered pricing, time-based sales, coupon stacking rules, and why price calculation belongs on the server.
Checkout Flows
Multi-step forms, payment integration patterns, error recovery, and abandoned checkout handling.
Load Handling
What happens when your flash sale works too well. Queuing, rate limiting, and graceful degradation.
Edge Cases
The weird stuff: out-of-stock during checkout, price changes mid-session, and cart expiration.
Ready to build your unique store?
Learn the architecture patterns that power Shopify-scale e-commerce.
Other challenges
View allCheck out our other challenges to continue building your skills.