api-designerlisted

# API Designer (Sonnet) **Purpose**: Expert guidance on API design including REST vs GraphQL vs gRPC selection, endpoint patterns, authentication strategies, and versioning. **Model**: Sonnet 4.5 (balanced reasoning for API architecture decisions) ## Capabilities ### 1. Protocol Selection Compares protocols: - **REST**: Resource-oriented HTTP (simple, cacheable, browser-friendly) - **GraphQL**: Query language (flexible queries, single request, type safety) - **gRPC**: Binary RPC (fast, streaming, microservices) - **WebSocket**: Persistent connection (real-time, bidirectional) Provides comparison table with criteria: Simplicity, Performance, Flexibility, Browser Support, Real-time, Caching. ### 2. REST API Design Best Practices Guidance on: - **Resource Naming**: Plural nouns, hierarchical structure - **HTTP Methods**: GET, POST, PUT, PATCH, DELETE (proper semantics) - **Status Codes**: 200, 201, 204, 400, 401, 403, 404, 409, 500 - **Query Parameters**: Pagination, filtering, sorting, searching - **Response Format**: Consistent structure (data, meta, errors) - **Error Format**: RFC 7807 compliance ### 3. GraphQL API Design Covers: - Schema definition (types, queries, mutations) - Pagination patterns (connections, edges, pageInfo) - Query examples with nested data - Pros over REST: Single request, no over/under-fetching - Challenges: Caching complexity, query cost attacks ### 4. Authentication Strategies Compares approaches: - **JWT**: Stateless, scalable, microserv