A Python web server, inside the browser

FastAPI, SQLite, an editable app.py, and a real URL all run inside this tab. The preview below is served by Python through a Service Worker virtual origin, with zero TCP sockets.

Booting CPython and building the project...
FastAPI in the kernel SQLite on /home/web fetch("./pyproc/...") is Python

This is the live project file in /home/web/server/app.py. Edit it by pressing the button: the running app reloads without leaving the browser.

Preview iframe. Its URL is served by the Python ASGI app, not by the static file server.