Django vs FastAPI vs Flask — Python Framework Decision Guide (2026)

Django, FastAPI and Flask are the three Python web frameworks most teams choose between. Each is strong at a different kind of work, and the wrong pick costs you months later. This guide compares them by app type, team and long-term maintenance, with migration paths and a sample stack for each.

1. The three in one paragraph each

Django is "batteries included": ORM, migrations, admin panel, authentication, forms, templates and a test framework in one package. It suits content-heavy sites, dashboards and internal tools. It has supported async views since Django 3.1 (2020) and async ORM methods since 4.1, but most Django code and most third-party apps are still synchronous.

FastAPI is an async-first API framework built on Starlette and Pydantic. It validates requests from type hints and generates OpenAPI documentation automatically. You choose the database layer, templates and auth yourself.

Flask is a microframework: routing, request handling and Jinja templates, and you add everything else from extensions. It gives maximum flexibility and little structure, which suits small projects and prototypes.

2. Decision matrix

3. Performance: what actually matters

For a trivial "hello world", an async FastAPI app on Uvicorn usually handles more requests per second than Flask or Django on Gunicorn, and the gap widens when handlers wait on databases or other services. Once real database queries, templates and business logic are involved, the difference shrinks, and query design, connection pooling and caching matter far more than the framework.

Published benchmarks vary widely with the setup, so measure your own app with a load-testing tool such as wrk, k6 or Locust on the server you will actually use before choosing a framework for speed alone.

4. When each one wins

Django

• Content sites such as blogs, news and magazines.
• Internal tools and back offices: the admin panel gives you CRUD screens for free.
• Forms-heavy apps such as invoicing and HR systems.
• E-commerce with a custom backend (Saleor and Oscar are built on Django).
• Multi-tenant SaaS, for example with django-tenants.

FastAPI

• Public REST APIs and backends for single-page apps and mobile apps.
• ML model serving, where many inference examples use FastAPI.
• WebSocket apps such as chat and live dashboards.
• Webhook receivers and microservices with many outbound calls.

Flask

• Prototypes and teaching.
• Data dashboards (Plotly Dash is built on Flask).
• Small single-purpose services.
• Existing Flask codebases: don't rewrite a working app without a reason.

5. Migrating between them

Flask to FastAPI (common)

Route handlers translate fairly directly:

# Flask
@app.route("/users/<int:user_id>")
def get_user(user_id):
    user = db.session.get(User, user_id)
    return jsonify(user.to_dict())

# FastAPI
@app.get("/users/{user_id}", response_model=UserOut)
async def get_user(user_id: int, session: AsyncSession = Depends(get_session)):
    user = await session.get(User, user_id)
    return user

The main changes:

• decorators are per HTTP method (@app.get, @app.post);
• you return Pydantic models or dicts instead of calling jsonify;
• dependencies come through Depends(...) instead of Flask's g object;
• handlers can be async def, but only if everything they call is async too.

SQLAlchemy 2.x supports both sync and async sessions, so you can keep your models and migrate route by route.

Django to FastAPI (usually don't)

Django's admin, ORM and forms are deeply integrated. If a Django app needs an API, add Django REST Framework or django-ninja (FastAPI-style syntax on Django) instead. For a new, API-only service, start with FastAPI.

Flask to Django (rare)

Usually unnecessary. Do it only if you need Django's admin and conventions badly enough to justify a rewrite.

6. Sample stacks for 2026

Check each project's release notes for the current version before you start; prefer a Django LTS release for long-lived projects.

Django:

Django (current LTS) + PostgreSQL + Redis (cache, sessions)
+ Celery for background jobs
+ Django REST Framework or django-ninja for APIs
+ django-allauth (social login)
+ django-htmx for dynamic pages without an SPA
+ Tailwind CSS

FastAPI:

FastAPI + PostgreSQL + SQLAlchemy 2 (async) with asyncpg + Alembic
+ Pydantic 2 for schemas
+ Celery, Arq or Dramatiq for background jobs
+ PyJWT for tokens
+ SlowAPI for rate limiting

See our FastAPI production deployment guide.

Flask:

Flask 3 + PostgreSQL + SQLAlchemy 2 + Flask-Migrate
+ Flask-Login (auth)
+ Flask-WTF (forms)
+ Celery or RQ for background jobs

7. Deployment patterns

On a VPS, all three follow the same pattern:

1. an app server: Gunicorn for Django and Flask (WSGI), Uvicorn or Gunicorn with Uvicorn workers for FastAPI (ASGI);
2. a systemd service to keep it running;
3. nginx as a reverse proxy;
4. a Let's Encrypt certificate.

Django and FastAPI can also live side by side, sharing one database:

/api/    -> FastAPI on 127.0.0.1:8000
/admin/  -> Django on 127.0.0.1:8001

This is a valid pattern: use the Django admin internally and ship a FastAPI public API. For Django specifically, work through our Django production deployment checklist.

8. Common pitfalls

Django

FastAPI

Flask

9. Running these frameworks on Domain India

• Shared hosting (cPanel and DirectAdmin): the Python app tool runs WSGI apps through Passenger, which suits small Django and Flask sites. FastAPI is an ASGI framework and async servers such as Uvicorn are not how that tool runs apps, and shared plans have no Redis or long-running background workers. See how to deploy a Python app on shared hosting.
• App Platform: Node.js is detected automatically; a Python app needs a Dockerfile. The App Platform does not support WebSockets, so use a VPS for FastAPI apps that rely on them. See getting started with the App Platform.
• VPS: full root access for Gunicorn or Uvicorn, systemd, nginx, PostgreSQL, Redis and Celery. Our VPS plans are self-managed: you install and maintain the software yourself.

The plan card shows the Domain India list price, excluding 18% GST.

Frequently asked questions

Ready to deploy? Try a small app on shared hosting, compare our VPS plans, or open a support ticket if you are not sure which fits.