The author of PySheets here: The app is written entirely in Python, running on PyScript, using PyScript-LTK, with two Python VMs, MicroPython and PyOdide. Web server is minimal logic, running on gunicorn on DigitalOcean. Storage is on Firestore. The App can be easily packaged up as a standalone, "on-prem" app, but I have not given that too much priority for now. Would love to hear what you all thing of writing web apps in the browser in Python.