api-design-principles

# API Design Principles Master REST and GraphQL API design principles to build intuitive, scalable, and maintainable APIs that delight developers and stand the test of time. ## When to Use This Skill - Designing new REST or GraphQL APIs - Refactoring existing APIs for better usability - Establishing API design standards for your team - Reviewing API specifications before implementation - Migrating between API paradigms (REST to GraphQL, etc.) - Creating developer-friendly API documentation - Optimizing APIs for specific use cases (mobile, third-party integrations) ## Core Concepts ### 1. RESTful Design Principles **Resource-Oriented Architecture** - Resources are nouns (users, orders, products), not verbs - Use HTTP methods for actions (GET, POST, PUT, PATCH, DELETE) - URLs represent resource hierarchies - Consistent naming conventions **HTTP Methods Semantics:** - `GET`: Retrieve resources (idempotent, safe) - `POST`: Create new resources - `PUT`: Replace entire resource (idempotent) - `PATCH`: Partial resource updates - `DELETE`: Remove resources (idempotent) ### 2. GraphQL Design Principles **Schema-First Development** - Types define your domain model - Queries for reading data - Mutations for modifying data - Subscriptions for real-time updates **Query Structure:** - Clients request exactly what they need - Single endpoint, multiple operations - Strongly typed schema - Introspection built-in ### 3. API Versioning Strategies **URL Versioning:** ``` /api/v1...