FastAPI vs Django: Choosing the Right Python Backend

Introduction

Python remains one of the most popular languages for backend development, and two frameworks dominate the landscape: Django and FastAPI. Each has its strengths and ideal use cases. Let's explore when to use each framework.

Django: The Batteries-Included Framework

Django has been the go-to Python web framework since 2005. It follows the "batteries-included" philosophy, providing everything you need out of the box.

Django Strengths:

• Admin Panel - Automatic admin interface
• ORM - Powerful database abstraction
• Authentication - Built-in user management
• Security - Protection against common vulnerabilities
• Mature Ecosystem - Thousands of packages

Django Example:

# models.py
from django.db import models

class Product(models.Model):
    name = models.CharField(max_length=200)
    price = models.DecimalField(max_digits=10, decimal_places=2)
    description = models.TextField()
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.name


# views.py
from rest_framework import viewsets
from .models import Product
from .serializers import ProductSerializer

class ProductViewSet(viewsets.ModelViewSet):
    queryset = Product.objects.all()
    serializer_class = ProductSerializer


# serializers.py
from rest_framework import serializers
from .models import Product

class ProductSerializer(serializers.ModelSerializer):
    class Meta:
        model = Product
        fields = '__all__'

FastAPI: The Modern, Fast Framework

FastAPI is a modern, high-performance framework built on Starlette and Pydantic. It's designed for building APIs quickly with automatic documentation.

FastAPI Strengths:

• Performance - One of the fastest Python frameworks
• Type Hints - Full Python type annotation support
• Auto Documentation - Swagger/OpenAPI out of the box
• Async Support - Native async/await
• Data Validation - Automatic with Pydantic

FastAPI Example:

# main.py
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from typing import List, Optional
from decimal import Decimal

app = FastAPI(title="Product API")

class Product(BaseModel):
    id: Optional[int] = None
    name: str
    price: Decimal
    description: str

# In-memory storage (use a database in production)
products: List[Product] = []

@app.get("/products", response_model=List[Product])
async def get_products():
    return products

@app.post("/products", response_model=Product)
async def create_product(product: Product):
    product.id = len(products) + 1
    products.append(product)
    return product

@app.get("/products/{product_id}", response_model=Product)
async def get_product(product_id: int):
    for product in products:
        if product.id == product_id:
            return product
    raise HTTPException(status_code=404, detail="Product not found")

Performance Comparison

FastAPI significantly outperforms Django in raw performance benchmarks:

| Metric | Django | FastAPI | |--------|--------|---------| | Requests/sec | ~2,000 | ~15,000 | | Latency (p99) | ~50ms | ~5ms | | Memory Usage | Higher | Lower |

Note: Actual numbers vary based on hardware and workload

Feature Comparison

| Feature | Django | FastAPI | |---------|--------|---------| | Admin Panel | ✅ Built-in | ❌ Manual | | ORM | ✅ Django ORM | ❌ SQLAlchemy (separate) | | Authentication | ✅ Built-in | ❌ Manual/JWT | | API Documentation | ❌ DRF required | ✅ Automatic | | Async Support | ⚠️ Partial | ✅ Native | | Type Hints | ⚠️ Optional | ✅ Required | | Learning Curve | Steeper | Easier |

When to Choose Django

Choose Django when:

1. Building full-stack applications with templates
2. Need an admin panel for content management
3. Working on large, complex projects with many features
4. Team is familiar with Django
5. Need rapid prototyping with built-in features
6. Building CMS or e-commerce platforms

When to Choose FastAPI

Choose FastAPI when:

1. Building pure APIs (REST or GraphQL)
2. Performance is critical for your use case
3. Working with microservices architecture
4. Need automatic API documentation
5. Using async operations extensively
6. Building ML/AI serving endpoints

Combining Both: Best of Both Worlds

You can use both frameworks together:

# Django for admin and complex features
# FastAPI for high-performance API endpoints

# Use Django ORM with FastAPI
from django.conf import settings
settings.configure(DATABASES={...})

import django
django.setup()

from myapp.models import Product

@app.get("/products")
async def get_products():
    products = await Product.objects.all()
    return products

Our Recommendation

At Space2Code, we recommend:

• Django for full-stack applications, admin-heavy projects, and rapid prototyping
• FastAPI for microservices, high-performance APIs, and ML/AI applications

Conclusion

Both Django and FastAPI are excellent choices for Python backend development. Django provides a complete solution for complex applications, while FastAPI offers modern performance and developer experience for API development.

Need help building your Python backend? Contact Space2Code for expert development services.