Agent skill · software engineering · daffy0208
API Designer
Design REST and GraphQL APIs. Use when creating backend APIs, defining API contracts, or integrating third-party services. Covers endpoint design, authentication, versioning, documentation, and best practices.
Why this skill is useful
Provides specific design patterns and standards for REST and GraphQL APIs that the AI wouldn't reliably generate on its own.
What it needs
About 6k tokens when loaded. Last updated 2025-12-25. 33 stars on the source repository.
What this skill does
API Designer Design robust, scalable, and developer-friendly APIs. Core Principles 1. Developer Experience First Clear, predictable naming conventions Comprehensive documentation Helpful error messages Consistent patterns across endpoints 2. Design for Evolution Versioning strategy from day one Backward compatibility Deprecation process Migration guides for breaking changes 3. Security by Default Authentication and authorization Rate limiting and throttling Input validation and sanitization HTTPS only, no exceptions 4. Performance Matters Efficient queries and indexing Caching strategies Pagination for large datasets Compression (gzip, brotli) REST API Design Resource Naming Conventions HTTP Methods & Semantics Method Purpose Idempotent Safe Request Body Response Body ---------- ---------------- ---------- ---- ------------ --------------- GET Retrieve data Yes Yes No Yes POST Create resource No No Yes Yes (created) PUT Replace resource Yes No Yes Yes (optional) PATCH Partial update No No Yes Yes (optional) DELETE Remove resource Yes No No No (204) or Yes Idempotent: Multiple identical requests have same effect as single request Safe: Request doesn't modify server state HTTP Status Codes Success (2xx): 200 OK - Successful GET, PUT, PATCH, DELETE 201 Created - Successful POST, includes Location header 204 No Content - Successful request, no response body (often DELETE) Client Errors (4xx): 400 Bad Request - Invalid syntax, validation error 401 Unauthorized - Authentication required or failed 403 Forbidden - Authenticated but lacks permission 404 Not Found - Resource doesn't exist 409 Conflict - Request conflicts with current state 422 Unprocessable Entity - Validation error (semantic) 429 Too Many Requests - Rate limit exceeded Server Errors (5xx): 500 Internal Server Error - Generic server error 502 Bad Gateway - Upstream service error 503 Service Unavailable - Temporary unavailability 504 Gateway Timeout - Upstream timeout Response Format Standards Success Response …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills daffy0208/api-designer