Django vs FastAPI: Which Framework Should You Choose for Your Backend?

The Quick Answer

Choose Django if you are building a full-featured web application, SaaS platform, e-commerce site, or any project that needs an admin panel, ORM, authentication, and a mature ecosystem out of the box. Choose FastAPI if you are building a high-performance microservice, a real-time API, or a lightweight service that needs async capabilities and maximum speed.

In practice, most business applications are better served by Django. FastAPI shines in specific scenarios. This article explains when to use each, based on my experience delivering 15+ commercial backend projects with both frameworks.

Django: The Batteries-Included Framework

What Django Does Well

Django is a full-stack web framework that gives you everything you need to build a production-ready application from day one:

• ORM (Object-Relational Mapper) — define your data models in Python, and Django handles SQL generation, migrations, and query optimization
• Admin panel — a free, customizable admin interface that is generated automatically from your models. This alone saves weeks of development on every project.
• Authentication system — user registration, login, password reset, permissions, and groups are built-in
• Django REST Framework (DRF) — the gold standard for building REST APIs in Python, with serialization, pagination, filtering, authentication, and browsable API documentation
• Migrations — database schema changes are tracked, versioned, and applied automatically
• Security — CSRF protection, SQL injection prevention, XSS protection, and clickjacking prevention are enabled by default
• Massive ecosystem — thousands of packages for everything from multi-tenancy to Stripe integration to full-text search

When to Choose Django

• SaaS platforms — multi-tenant applications with user management, billing, and admin dashboards
• E-commerce sites — product catalogs, shopping carts, payment processing, order management
• Content-heavy applications — CMS features, blog platforms, real estate listing sites
• Internal business tools — CRM replacements, employee management systems, reporting dashboards
• Any project that needs an admin panel — Django admin is unmatched in the Python ecosystem
• Projects where development speed matters — Django's conventions and built-in features mean less code to write and maintain

Django's Limitations

• Synchronous by default — Django's traditional request/response cycle is synchronous, which can be a bottleneck for I/O-heavy workloads (though Django 4.1+ supports async views)
• Heavier footprint — Django includes a lot of functionality you may not need for a simple API service
• Less flexible routing — Django's URL configuration is powerful but more verbose than FastAPI's decorator-based approach

FastAPI: The Performance-First Framework

What FastAPI Does Well

• Async native — built on Starlette and Pydantic, FastAPI is async from the ground up, making it ideal for I/O-bound workloads
• Automatic documentation — generates OpenAPI (Swagger) and ReDoc documentation from your type hints
• Type safety — uses Python type hints and Pydantic models for request/response validation, giving you runtime type checking
• Raw performance — one of the fastest Python web frameworks available, comparable to Node.js and Go for simple API endpoints
• Lightweight — minimal overhead, no unnecessary features

When to Choose FastAPI

• Microservices — standalone API services that do one thing well (authentication service, notification service, data processing pipeline)
• Real-time applications — WebSocket servers, live data streaming, chat backends
• AI and ML APIs — serving machine learning models that need high throughput and async processing
• High-performance APIs — when you need maximum requests per second from a Python service
• API-only services — when you do not need an admin panel, ORM, or built-in authentication

FastAPI's Limitations

• No built-in ORM — you need to bring your own (SQLAlchemy, Tortoise ORM, or raw SQL). This means more boilerplate for database operations.
• No admin panel — you either build one from scratch or use a third-party package that does not match Django admin's maturity
• Smaller ecosystem — fewer battle-tested packages for common tasks like multi-tenancy, payment processing, or content management
• More decisions to make — Django's opinions save time. FastAPI's flexibility means you need to choose and configure more components yourself.

Head-to-Head Comparison

Can You Use Both?

Yes, and I often do. A common architecture for complex systems is:

• Django as the main application backend — handling user management, admin panel, business logic, and database operations
• FastAPI as a secondary service — handling high-throughput API endpoints, WebSocket connections, or ML model serving

Both frameworks speak Python, both work with PostgreSQL and Redis, and both deploy cleanly with Docker. Using them together gives you the best of both worlds.

My Recommendation

For 90% of business applications I encounter, Django is the right choice. The admin panel alone saves weeks of development. The ORM, authentication system, and DRF provide a complete foundation that lets you focus on business logic instead of infrastructure.

FastAPI is the right choice when you are building a specific type of service — a real-time API, an ML inference endpoint, or a lightweight microservice that does not need Django's batteries. But for a SaaS platform, e-commerce store, or business tool? Django wins every time.

As a Django developer based in Barcelona, I have built both types of systems and can help you choose the right architecture for your specific project. Get in touch for a free consultation.