Write complete web applications in Python without writing javascript. There are a large class of problems for which this is an excellent solution, without having to dip into the javascript tarpit.
The advantage of something like this over using templates is that you can think of “widgets” vs “templates”.
Some frameworks are:
Reflex (formerly known as pynecone). Uses FastAPI + React.
NiceGUI. Uses FastAPI + Vue.js + Quasar, tailwind.
Pydantic/FastUI. Uses React. still early in development.
Gradio — “Build & Share Delightful Machine Learning Apps”