What problem does it solve? Choosing the wrong API style or shipping inconsistent endpoints leads to costly rewrites and integration friction. This Skill provides decision frameworks for selecting between REST, GraphQL, and tRPC, plus concrete rules for response formats, versioning, authentication, and rate limiting. ## Core Features & Use Cases - API Style Selection: Decision trees comparing REST, GraphQL, and tRPC based on consumers, type safety, and caching needs. - Design References: In-depth guides covering resource naming, HTTP status codes, pagination strategies, JWT/OAuth/Passkey auth, and OWASP API Top 10 security testing. - Automated Validation: A Python script that scans API code and OpenAPI specs for missing error handling, status codes, validation, and rate limiting. - Use Case: When designing a new public API for a TypeScript monorepo, consult the decision tree to pick tRPC, then run the validator script against your endpoints before deployment. ## Quick Start Ask the AI to help design a REST API for a user management service, including response format, versioning, and authentication strategy.