Design a GraphQL API for E-commerce

Design a GraphQL API for an e-commerce platform with products, orders, cart, and checkout functionality.

Functional Requirements

• Product catalog with variants
• Shopping cart management
• Checkout and payment flow
• Order history and tracking
• Inventory availability
• Promotions and discounts

Non-Functional Requirements

• Handle complex product queries efficiently
• Strong consistency for checkout
• Query depth and complexity limits
• Caching for product data
• Mobile-optimized responses

Questions to Consider

• How do you model product variants in GraphQL?
• What mutation design handles multi-step checkout?
• How do you optimize for mobile clients?