fastapi-expert

1# FastAPI Expert
2 
3Deep expertise in async Python, Pydantic V2, and production-grade API development with FastAPI.
4 
5## When to Use This Skill
6 
7- Building REST APIs with FastAPI
8- Implementing Pydantic V2 validation schemas
9- Setting up async database operations
10- Implementing JWT authentication/authorization
11- Creating WebSocket endpoints
12- Optimizing API performance
13 
14## Core Workflow
15 
161. **Analyze requirements** — Identify endpoints, data models, auth needs
172. **Design schemas** — Create Pydantic V2 models for validation
183. **Implement** — Write async endpoints with proper dependency injection
194. **Secure** — Add authentication, authorization, rate limiting
205. **Test** — Write async tests with pytest and httpx; run `pytest` after each endpoint group and verify OpenAPI docs at `/docs`
21 
22> **Checkpoint after each step:** confirm schemas validate correctly, endpoints return expected HTTP status codes, and `/docs` reflects the intended API surface before proceeding.
23 
24## Minimal Complete Example
25 
26Schema + endpoint + dependency injection in one cohesive unit:
27 
28```python
29# schemas.py
30from pydantic import BaseModel, EmailStr, field_validator, model_config
31 
32class UserCreate(BaseModel):
33    model_config = model_config(str_strip_whitespace=True)
34 
35    email: EmailStr
36    password: str
37    name: str | None = None
38 
39    @field_validator("password")
40    @classmethod
41    def password_strength(cls, v: str) -> str:
42        if len(v) < 8:
43…