Using the Web Port

MicroPythonOS can run entirely in a web browser thanks to a WebAssembly build. This is the easiest way to try the latest bleeding-edge code without flashing hardware.

Live demo

The latest main branch is automatically built and published to GitHub Pages:

MicroPythonOS.github.io/MicroPythonOS

Open that link in a modern desktop browser and the OS will boot directly into the launcher.

Refreshing the filesystem

The web port stores writable data (/data and /apps) in the browser's IndexedDB. The read-only system files are baked into the WebAssembly preload. If you want a completely clean start — for example, after a major upstream change or to clear stale app data — you need to wipe the stored filesystem:

1. Open the developer tools (F12).
2. Go to Application → Storage → Local Storage / IndexedDB (or the equivalent in your browser).
3. Clear site data / delete everything for micropythonos.github.io.
4. Close the tab or press F5 to reload the page.

After the reload the OS will boot with a fresh filesystem. The bundled demo apps will be re-seeded on first run.

Limitations in the browser

The web port is a faithful approximation of the real OS, but a browser is not a microcontroller. Expect the following differences:

• No raw network sockets — HTTP is handled through the browser's fetch() API, and CORS applies to cross-origin requests.
• No Bluetooth, ADC, IMU, or camera — hardware-specific features either raise errors or return stubs.
• Persistence is per-origin — clearing site data wipes /data and /apps.

For everything else, the web port behaves like a desktop build: the same apps, the same launcher, and the same Python runtime.

Reporting issues

If the live demo fails to boot, open the browser console and look for fatal errors such as memory access out of bounds, function signature mismatch, or MicroPythonOS exiting. Transient messages like no ADC, fetch failed, or aiorepl ... EIO are expected and harmless.