GRAPHQL Schema Design

GraphQL Schema Design

Designing GraphQL schemas for flexible, efficient APIs.

Context

You are designing a GraphQL schema. Think about types, fields, queries, mutations.

Domain Context

• Types: Nouns (User, Order, Product); fields are attributes
• Queries: Read operations; no side effects
• Mutations: Write operations; return results
• Subscriptions: Real-time updates via WebSocket
• Fragments: Reusable selections; avoid duplication

Instructions

1. Define Types: User, Order, Product; what fields do they have?
2. Design Queries: Root query type; what can clients read?
3. Design Mutations: Root mutation type; what can clients change?
4. Use Enums: For fixed sets of values (OrderStatus, Role)
5. Use Interfaces: For shared fields across types (Node interface)
6. Plan Subscriptions: Real-time updates? What events?
7. Document Null: Mark required fields with !

Anti-Patterns

• Over-nesting types; leads to N+1 query problems
• Allowing mutations without auth checks; easy backdoors
• No rate limiting on mutations; clients can spam writes
• Exposing internal IDs directly; abstract away
• Not planning pagination; large result sets kill performance

Further Reading

• GraphQL spec and best practices
• Apollo GraphQL docs
• Hasura GraphQL patterns