Python

Cloudflare Python Workers use the workers SDK, a WorkerEntrypoint class, and the python_workers compatibility flag. Python Workers are currently beta.

open-compute supports Python modules inside a native Worker Loader child on the certified 2026-09-08 compatibility date. The pinned Pyodide bundle is embedded in ocd, so production startup does not download a Python runtime.

Configure the parent Worker

Declare a Worker Loader binding in the parent project’s wrangler.jsonc:

{
  "$schema": "./node_modules/wrangler/config-schema.json",
  "name": "python-loader",
  "main": "src/index.ts",
  "compatibility_date": "2026-09-08",
  "worker_loaders": [{ "binding": "LOADER" }]
}

Load a Python child

The Python child follows Cloudflare’s WorkerEntrypoint model. The parent supplies the Python module and invokes its default entrypoint:

interface Env {
  LOADER: WorkerLoader;
}

const pythonSource = `
from workers import WorkerEntrypoint, Response

class Default(WorkerEntrypoint):
    async def fetch(self, request):
        return Response("Hello from Python!")
`;

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const child = env.LOADER.load({
      compatibilityDate: "2026-09-08",
      compatibilityFlags: ["python_workers"],
      mainModule: "main.py",
      globalOutbound: null,
      modules: {
        "main.py": { py: pythonSource },
      },
    });

    return child.getEntrypoint().fetch(request);
  },
} satisfies ExportedHandler<Env>;

Deploy the parent with the project-local certified Wrangler:

ocd wrangler deploy

Direct deployment of a Python file as an ordinary Worker’s main through pywrangler is not currently part of open-compute’s public upload contract. Use the Worker Loader path above. Explicit child limits, including an empty object, are also rejected until standard CPU, memory, and subrequest enforcement is available.

Cloudflare reference: Python Workers.