FastAPI vs Django REST Framework：性能・機能比較と選択指針 2026年版

# FastAPIの例
from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()

class User(BaseModel):
    name: str
    email: str

@app.post("/users/")
async def create_user(user: User):
    # 非同期処理でデータベース操作
    return {"message": "User created", "user": user}

# Django REST Frameworkの例
from rest_framework.views import APIView
from rest_framework.response import Response
from .serializers import UserSerializer

class UserCreateView(APIView):
    def post(self, request):
        serializer = UserSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.errors)

import asyncio
import aiohttp

@app.get("/external-data/")
async def get_external_data():
    async with aiohttp.ClientSession() as session:
        # 複数の外部API呼び出しを並行実行
        tasks = [
            fetch_user_data(session, user_id)
            for user_id in range(1, 11)
        ]
        results = await asyncio.gather(*tasks)
    return {"results": results}

from fastapi import FastAPI, Query
from typing import Optional

app = FastAPI(
    title="User API",
    description="ユーザー管理API",
    version="1.0.0"
)

@app.get("/users/")
async def read_users(
    limit: int = Query(10, description="取得する件数", ge=1, le=100),
    offset: int = Query(0, description="オフセット", ge=0)
):
    """
    ユーザー一覧を取得します。

    - **limit**: 取得件数（1-100）
    - **offset**: 開始位置
    """
    return {"users": [], "total": 0}

from pydantic import BaseModel, EmailStr, validator
from typing import Optional
from datetime import datetime

class UserCreate(BaseModel):
    username: str
    email: EmailStr
    age: int
    is_active: bool = True
    created_at: Optional[datetime] = None

    @validator('age')
    def validate_age(cls, v):
        if v < 0 or v > 150:
            raise ValueError('年齢は0-150の範囲で入力してください')
        return v

from rest_framework import serializers
from django.contrib.auth.models import User

class UserSerializer(serializers.ModelSerializer):
    password = serializers.CharField(write_only=True)

    class Meta:
        model = User
        fields = ['username', 'email', 'password']

    def validate_username(self, value):
        if User.objects.filter(username=value).exists():
            raise serializers.ValidationError("ユーザー名は既に存在します")
        return value

# FastAPI + SQLAlchemy
from sqlalchemy.ext.asyncio import AsyncSession
from fastapi import Depends

async def create_user_service(
    user_data: UserCreate,
    db: AsyncSession = Depends(get_db)
):
    db_user = User(**user_data.dict())
    db.add(db_user)
    await db.commit()
    await db.refresh(db_user)
    return db_user

# DRFのViewSet
from rest_framework.viewsets import ModelViewSet
from rest_framework.permissions import IsAuthenticated
from django_filters.rest_framework import DjangoFilterBackend

class UserViewSet(ModelViewSet):
    queryset = User.objects.all()
    serializer_class = UserSerializer
    permission_classes = [IsAuthenticated]
    filter_backends = [DjangoFilterBackend]
    filterset_fields = ['is_active', 'date_joined']

from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from fastapi import Depends, HTTPException
import jwt

security = HTTPBearer()

async def verify_token(credentials: HTTPAuthorizationCredentials = Depends(security)):
    try:
        payload = jwt.decode(credentials.credentials, SECRET_KEY, algorithms=["HS256"])
        return payload
    except jwt.PyJWTError:
        raise HTTPException(status_code=401, detail="Invalid token")

@app.get("/protected/")
async def protected_route(current_user: dict = Depends(verify_token)):
    return {"message": "認証成功", "user": current_user}

from rest_framework.permissions import IsAuthenticated
from rest_framework.authentication import TokenAuthentication
from rest_framework.throttling import UserRateThrottle

class UserViewSet(ModelViewSet):
    authentication_classes = [TokenAuthentication]
    permission_classes = [IsAuthenticated]
    throttle_classes = [UserRateThrottle]

    def get_queryset(self):
        # ユーザーごとのデータフィルタリング
        return User.objects.filter(owner=self.request.user)

# Dockerfile例
FROM python:3.11-slim

WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt

COPY . .

CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]

# settings.py（本番設定）
import os

DEBUG = False
ALLOWED_HOSTS = ['.example.com']

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': os.environ['DB_NAME'],
        'USER': os.environ['DB_USER'],
        'PASSWORD': os.environ['DB_PASSWORD'],
        'HOST': os.environ['DB_HOST'],
        'PORT': os.environ['DB_PORT'],
    }
}

# セキュリティ設定
SECURE_SSL_REDIRECT = True
SECURE_HSTS_SECONDS = 3600