Import Python utilities directly in JS

// main thread
const { ffi: { func_a, func_b } } = await import('./test.js');

// test.js
import bridge from 'https://esm.run/@pyscript/bridge';
export const ffi = bridge(import.meta.url, { type: 'mpy', worker: false });

// test.py
def func_a(value):
    print(f"hello {value}")

def func_b():
    import sys
    return sys.version

• pyscript: the release version to automatically import if not already available on the page. If no version is provided the developers' channel version will be used instead (for developers' purposes only).
• type: py by default to bootstrap Pyodide.
• worker: true by default to bootstrap in a Web Worker.
• config: either a string or a PyScript compatible config JS literal to make it possible to bootstrap files and whatnot. If specified, the worker becomes implicitly true to avoid multiple configs conflicting on the main thread.
• env: to share the same environment across multiple modules loaded at different times.

Run npx mini-coi . within this folder to then reach out http://localhost:8080/test/ that will show:

PyScript Bridge
------------------
no config

The test.js files uses the following defaults:

• pyscript as "2025.8.1"
• type as "mpy"
• worker as false
• config as undefined
• env as undefined

To test any variant use query string parameters so that ?type=py will use py instead, worker will use a worker and config will use a basic config that brings in another file from the same folder which exposes the version.

To recap: http://localhost:8080/test/?type=py&worker&config will show this instead:

PyScript Bridge
------------------
3.12.7 (main, May 15 2025, 18:47:24) ...

Please note when a config is used, the worker attribute is always true.