Serverless in-browser UI via pyodide

[yhcharles]

With Pyodide, one can run Python code in browser -- without backend server. This enables the possibility to create pure frontend UI with Python.

A few other Python UI frameworks has already enabled this feature:

• gradio: https://www.gradio.app/guides/gradio-lite
• panel: https://panel.holoviz.org/how_to/wasm/index.html
• streamlit: https://github.com/whitphx/stlite

How about bringing this feature to NiceGUI?

[rodja]

Wow. I was not aware of Pyodide. Looks very interesting but we currently do not have the resources to investigate a possible integration. We are very grateful for any help in this regard. A first interesting step would probably be a working prototype of Starlette or FastAPI running in the browser.

[yhcharles]

Thanks for the reply. I think we may not need to bring the whole FastAPI in browser. That could be too heavy.

I'm not familiar with the implementation details of NiceGUI, but to my understanding the UI part is done in html/JS, which communicates with backend Python server to handle user actions. If that's true, the Python server won't be necessary if using Pyodide. JS and Python can call each other directly in the browser.

[rodja]

But then you would need to rewrite all the routing code. Surely possible but would require additional maintainace.

[yhcharles]

Yes, it could be a large change. Not sure how other libraries achieved this, like gradio & panel. Maybe there's something we can learn from them.

[trungleduc]

Hi folks, I'm building a library that can serve Starlette apps in the browser, and it supports NiceGUI. Here is the discussion #5701

[yhcharles]

Thanks! This looks very interesting and promising!

[evnchn]

Crazy! And a bit scary. 🤯

#5776

[evnchn]

@yhcharles — this exists now 🧪 (alpha): https://github.com/evnchn/nicegui-pyodide

An external extension to stock NiceGUI (no fork, no core changes) that runs NiceGUI entirely in the browser via Pyodide/PyScript — no server. pip install nicegui + the extension, then nicegui-pyodide-build ./dist gives you a static folder to host anywhere.

Alpha: pinned to NiceGUI 3.14.x; verified surface is small (basic widgets, click→handler→DOM, ui.notify, markdown, input round-trip); no-server-only features (HTTP endpoints, static routes, native mode) don't apply. Feedback/issues welcome. It grew out of my closed core PR #5776, re-done as an external package.