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Terminal · npx$
npx skills add https://github.com/jeffallan/claude-skills --skill fastapi-expertWorks with Paperclip
How Fastapi Expert fits into a Paperclip company.
Fastapi Expert drops into any Paperclip agent that handles this kind of work. Assign it to a specialist inside a pre-configured PaperclipOrg company and the skill becomes available on every heartbeat — no prompt engineering, no tool wiring.
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SaaS FactoryPaired
Pre-configured AI company — 18 agents, 18 skills, one-time purchase.
$27$59
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SKILL.md185 linesExpandCollapse
---name: fastapi-expertdescription: "Use when building high-performance async Python APIs with FastAPI and Pydantic V2. Invoke to create REST endpoints, define Pydantic models, implement authentication flows, set up async SQLAlchemy database operations, add JWT authentication, build WebSocket endpoints, or generate OpenAPI documentation. Trigger terms: FastAPI, Pydantic, async Python, Python API, REST API Python, SQLAlchemy async, JWT authentication, OpenAPI, Swagger Python."license: MITmetadata: author: https://github.com/Jeffallan version: "1.1.0" domain: backend triggers: FastAPI, Pydantic, async Python, Python API, REST API Python, SQLAlchemy async, JWT authentication, OpenAPI, Swagger Python role: specialist scope: implementation output-format: code related-skills: fullstack-guardian, django-expert, test-master--- # FastAPI Expert Deep expertise in async Python, Pydantic V2, and production-grade API development with FastAPI. ## When to Use This Skill - Building REST APIs with FastAPI- Implementing Pydantic V2 validation schemas- Setting up async database operations- Implementing JWT authentication/authorization- Creating WebSocket endpoints- Optimizing API performance ## Core Workflow 1. **Analyze requirements** — Identify endpoints, data models, auth needs2. **Design schemas** — Create Pydantic V2 models for validation3. **Implement** — Write async endpoints with proper dependency injection4. **Secure** — Add authentication, authorization, rate limiting5. **Test** — Write async tests with pytest and httpx; run `pytest` after each endpoint group and verify OpenAPI docs at `/docs` > **Checkpoint after each step:** confirm schemas validate correctly, endpoints return expected HTTP status codes, and `/docs` reflects the intended API surface before proceeding. ## Minimal Complete Example Schema + endpoint + dependency injection in one cohesive unit: ```python# schemas.pyfrom pydantic import BaseModel, EmailStr, field_validator, model_config class UserCreate(BaseModel): model_config = model_config(str_strip_whitespace=True) email: EmailStr password: str name: str | None = None @field_validator("password") @classmethod def password_strength(cls, v: str) -> str: if len(v) < 8: raise ValueError("Password must be at least 8 characters") return v class UserResponse(BaseModel): model_config = model_config(from_attributes=True) id: int email: EmailStr name: str | None = None``` ```python# routers/users.pyfrom fastapi import APIRouter, Depends, HTTPException, statusfrom sqlalchemy.ext.asyncio import AsyncSessionfrom typing import Annotated from app.database import get_dbfrom app.schemas import UserCreate, UserResponsefrom app import crud router = APIRouter(prefix="/users", tags=["users"]) DbDep = Annotated[AsyncSession, Depends(get_db)] @router.post("/", response_model=UserResponse, status_code=status.HTTP_201_CREATED)async def create_user(payload: UserCreate, db: DbDep) -> UserResponse: existing = await crud.get_user_by_email(db, payload.email) if existing: raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="Email already registered") return await crud.create_user(db, payload)``` ```python# crud.pyfrom sqlalchemy import selectfrom sqlalchemy.ext.asyncio import AsyncSessionfrom app.models import Userfrom app.schemas import UserCreatefrom app.security import hash_password async def get_user_by_email(db: AsyncSession, email: str) -> User | None: result = await db.execute(select(User).where(User.email == email)) return result.scalar_one_or_none() async def create_user(db: AsyncSession, payload: UserCreate) -> User: user = User(email=payload.email, hashed_password=hash_password(payload.password), name=payload.name) db.add(user) await db.commit() await db.refresh(user) return user``` ## JWT Authentication Snippet ```python# security.pyfrom datetime import datetime, timedelta, timezonefrom jose import JWTError, jwtfrom fastapi import Depends, HTTPException, statusfrom fastapi.security import OAuth2PasswordBearerfrom typing import Annotated SECRET_KEY = "read-from-env" # use os.environ / settingsALGORITHM = "HS256"oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/auth/token") def create_access_token(subject: str, expires_delta: timedelta = timedelta(minutes=30)) -> str: payload = {"sub": subject, "exp": datetime.now(timezone.utc) + expires_delta} return jwt.encode(payload, SECRET_KEY, algorithm=ALGORITHM) async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]) -> str: try: data = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM]) subject: str | None = data.get("sub") if subject is None: raise ValueError return subject except (JWTError, ValueError): raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid credentials") CurrentUser = Annotated[str, Depends(get_current_user)]``` ## Reference Guide Load detailed guidance based on context: | Topic | Reference | Load When ||-------|-----------|-----------|| Pydantic V2 | `references/pydantic-v2.md` | Creating schemas, validation, model_config || SQLAlchemy | `references/async-sqlalchemy.md` | Async database, models, CRUD operations || Endpoints | `references/endpoints-routing.md` | APIRouter, dependencies, routing || Authentication | `references/authentication.md` | JWT, OAuth2, get_current_user || Testing | `references/testing-async.md` | pytest-asyncio, httpx, fixtures || Django Migration | `references/migration-from-django.md` | Migrating from Django/DRF to FastAPI | ## Constraints ### MUST DO- Use type hints everywhere (FastAPI requires them)- Use Pydantic V2 syntax (`field_validator`, `model_validator`, `model_config`)- Use `Annotated` pattern for dependency injection- Use async/await for all I/O operations- Use `X | None` instead of `Optional[X]`- Return proper HTTP status codes- Document endpoints (auto-generated OpenAPI) ### MUST NOT DO- Use synchronous database operations- Skip Pydantic validation- Store passwords in plain text- Expose sensitive data in responses- Use Pydantic V1 syntax (`@validator`, `class Config`)- Mix sync and async code improperly- Hardcode configuration values ## Output Templates When implementing FastAPI features, provide:1. Schema file (Pydantic models)2. Endpoint file (router with endpoints)3. CRUD operations if database involved4. Brief explanation of key decisions ## Knowledge Reference FastAPI, Pydantic V2, async SQLAlchemy, Alembic migrations, JWT/OAuth2, pytest-asyncio, httpx, BackgroundTasks, WebSockets, dependency injection, OpenAPI/Swagger