Running NiceGUI app without backend

[trungleduc]

Hi all,

You may have heard of JupyterLite, a Wasm-powered JupyterLab running in the browser.

I'm developing JupyterPack, a JupyterLite extension that enables serving Python web applications directly in the browser using a Wasm-based Python kernel.

It currently supports NiceGUI applications, with features such as:

• Live preview with hot reloading inside JupyterLite
• Running the same app in a full-screen standalone mode
• Instantly share your NiceGUI app via a simple URL

By simply adding a #!jupyterpack.nicegui shebang to the top of your NiceGUI script, you can serve your app using JupyterPack.

Here’s a short screencast demonstrating the workflow:

nice-gui.mp4

You can try it out directly in JupyterLite

Or view the app in full-screen mode

Feedback and ideas are very welcome!

[evnchn]

You beat me to it. I was trying out something similar privately (wasted a month of Manus credits)

I'll put this in my favourites and review later.

[evnchn]

Note: my attempt is at https://github.com/evnchn/nicegui/tree/pyodide-support

It's frankly not very good 🤡

[trungleduc]

Hey @evnchn, my approach is simulating an ASGI and WSGI server in the browser, so it works with various Python libraries

[evnchn]

Hello @trungleduc I just realized that you use xeus not pyodide.

Does xeus fully run in the browser?

[trungleduc]

Yes, for jupyterlite you can use the xeus-python kernel or the pyodide kernel. I prefer xeus-python since you can define the packages of your environment at build time

[evnchn]

@trungleduc nice work — related: I've packaged a general approach as an extension, https://github.com/evnchn/nicegui-pyodide 🧪 (alpha).

It runs stock NiceGUI in-browser via Pyodide as an external package (no fork/core changes): a sys.modules fallback so NiceGUI's server-only imports resolve when absent, plus an in-process JS bridge replacing socket.io. nicegui-pyodide-build emits a static, hostable folder.

Given your Pyodide/JupyterLite background I'd genuinely value your eyes on the approach. Alpha caveats: pinned to 3.14.x, small verified surface, no-server features excluded.