CORS Configuration for FastAPI

What problem does it solve?

This Skill configures CORS (Cross-Origin Resource Sharing) for FastAPI to allow frontend requests across different origins, resolving common cross-origin errors that block legitimate UI-backend communication.

Core Features & Use Cases

• CORSMiddleware integration: Adds robust CORS handling to the FastAPI app with configurable origins, methods, and headers.
• Environment-driven origins: Reads allowed origins from environment variables (CORS_ORIGINS) for flexible deployment across development, staging, and production.
• Security-conscious defaults: Enables credentials and defines a safe preflight cache to balance security and performance.

Quick Start

Configure allowed origins in the environment (e.g., CORS_ORIGINS=http://localhost:3000). Then update backend/app/main.py to mount CORSMiddleware using the configured origins, and run the FastAPI server.