FastAPI

vs

ASP.NET Core

Flask is a micro framework framework written in Python that can be used to build APIs, web services and web applications. Flask is designed from the bottom up to be extremely minimal and easy to use, where your whole application can fit into one single Python file. The framework includes no database abstraction layer, form validation, or any other components, by design. However pre-existing third-party libraries provide common functionality needed to build production ready applications and services.

Bottle is a fast, simple and lightweight WSGI micro web-framework for Python. The framework can be used to create lean web applications with Python 2.7 and 3.x. Bottle is distributed as a single file module with no additional dependencies which makes it really easy to get started and later in the development-stage to manage.

Django is a high-level Python web development framework used for building web application at scale with speed. The framework adhere to a clean and pragmatic design that lets developers develop rapidly. Django ships as a "batteries included" framework and contains many of the features needed for most web applications such as an admin panel, an ORM and templating language. It takes much of the hassle out of web development and lets developers focus on writing their application instead of focusing on authentication, authorization and security.