MicroPython Stubs Playground

[Josverl]

I built a small web app to demonstrate something I think is still underused in MicroPython: static type checking with stubs — without any setup.

Try it now: https://josverl.github.io/stubs_playground/

What it does:

• Write MicroPython code in your browser
• Get real-time type checking and errors as you type
• Hover for documentation and type information from MicroPython stubs
• Switch between ESP32, RP2040, STM32, CircuitPython (more to come)
• Share code snippets via a simple link

Everything runs fully client-side (Pyright in a Web Worker), so there is no install and no server involved.

Why I made this:

• Show that type checking for MicroPython can be simple and accessible
• Help catch issues before runtime
• Provide an easy way to test code across ports
• Offer a proof of concept for Codemirror browser-based editors to start using using LSP and stubs to make coding better.

I would really appreciate feedback, ideas, or if you would like to reuse parts of this in other editors or tools.
and may I ask ; If you find this useful, please consider starring the repository just to let me know.

Red squiggles:

When (not if) you find a bug in the stubs, as in "code with red squiggle that actually runs perfectly fine", please report do it so I can de-squiggle it.
This is now just a matter of clicking the "Report issue" button in the UI, which will pre-fill a bug report with the relevant code snippet and diagnostics.
If you package the MicroPython-stubs in your tools, link to the Stubs Playground and ask your users to report it.
That is a huge help in improving the stubs for everyone.

[peterhinch]

Very impressive.

[Josverl]

Very impressive.

Thanks, the asyncio stubs have been tested against a few of your code samples. So thank you for these.