FastAPI Backend Development Skill

Overview

This skill focuses on building high-performance, production-ready REST APIs using FastAPI, SQLModel, and Pydantic. It emphasizes clean architecture, type safety, and efficient database management for modern web applications.

Core Capabilities

• •RESTful API Design: Structure endpoints logically by feature (e.g., /tasks, /users) using APIRouter.
• •Validation (Pydantic): Enforce strict data validation and serialization for request bodies and response models.
• •Persistence (SQLModel): Seamlessly integrate Python classes with SQL databases (PostgreSQL/Neon) using SQLModel ORM.
• •Dependency Injection: Manage database sessions, authentication, and configuration through FastAPI's robust DI system.
• •Security (JWT): Implement secure authentication and authorization patterns using JWT tokens and OAuth2 password flows.
• •Async Programming: Utilize async/await for non-blocking I/O operations (database queries, external API calls).

Best Practices

1. •Feature-Based Organization: Group routers, models, and services by feature rather than layer (e.g., src/features/tasks/...).
2. •Schema Separation: Use separate models for Table (SQLModel), Create (Pydantic), and Read (Pydantic) to avoid exposing internal IDs or passwords.
3. •Endpoint Typing: Always use response_model and type hints for path/query parameters.
4. •Error Handling: Centralize error responses using HTTPException and custom exception handlers.
5. •Environment Stability: Manage secrets and configuration via .env files using pydantic-settings.

Integration Highlights (Phase 2+)

• •Neon DB: Optimized for serverless PostgreSQL connections.
• •Better Auth Integration: Coordinating with Next.js frontend for secure session management.
• •CORS Configuration: Proper setup for multi-service communication between frontend and backend.

Example Usage

"Architect a task-management API with a PostgreSQL backend using SQLModel, including paginated list endpoints and optimistic locking."