Web Frameworks in Python

Django is the batteries-included choice: ORM, migrations, admin, authentication, forms and templates in one package, with a large ecosystem of reusable apps. It fits database-backed sites with users and content. Flask is a microframework that gives you routing, request handling and Jinja templates, and you choose extensions for the rest. Bottle goes smaller still, a single file with no dependencies outside the standard library. Pyramid sits in between, starting small and scaling to large apps through explicit configuration.

On the async side, Starlette is a lightweight ASGI toolkit and the base FastAPI is built on. Litestar is a complete ASGI framework with dependency injection, validation and OpenAPI generation. Tornado predates asyncio and is still used for long-lived connections. Reflex and FastHTML aim at building whole apps in Python: Reflex compiles your UI to a React frontend, while FastHTML returns server-rendered HTML and uses HTMX for interactivity.

Sync frameworks run under a WSGI server such as Gunicorn, and async ones under an ASGI server such as Uvicorn or Granian. Django also supports async views and ASGI deployment, so choosing it does not rule out async code. For JSON APIs rather than HTML pages, see the Web APIs section.