Python Workers

Cloudflare Workers provides a first-class Python experience, including support for:

• Easy to install and fast-booting Packages, including FastAPI , Langchain , Pydantic and more.
• A robust foreign function interface (FFI) that lets you use JavaScript objects and functions directly from Python including all Runtime APIs
• An ecosystem of services on the Workers Platform accessible via bindings, including:
  • State storage and databases like KV, D1, Durable Objects
  • Access to Environment Variables, Secrets, and other Workers using Service Bindings
  • AI capabilities with Workers AI, Vectorize
  • File storage with R2
  • Durable Workflows, Queues, and more

A Python Worker can be as simple as four lines of code:

from workers import WorkerEntrypoint, Response

class Default(WorkerEntrypoint):
    async def fetch(self, request):
        return Response("Hello World!")

Similar to other Workers, the main entry point for a Python worker is the fetch handler which handles incoming requests sent to the Worker.

In a Python Worker, this handler is placed in a Default class that extends the WorkerEntrypoint class (which you can import from the workers SDK module).

To run a Python Worker locally, install packages, and deploy it to Cloudflare, you use pywrangler , the CLI for Python Workers.

To set it up, first, ensure uv and Node are installed.

Then set up your development environment:

uvx --from workers-py pywrangler init

This will create a pyproject.toml file with workers-py as a development dependency. pywrangler init will create a wrangler config file. You can then run pywrangler with:

uv run pywrangler dev

To deploy a Python Worker to Cloudflare, run pywrangler deploy:

uv run pywrangler deploy

When you initialize a new Python Worker project and select from one of many templates:

uv run pywrangler init

Or you can clone the examples repository to explore more options:

git clone https://github.com/cloudflare/python-workers-examples
cd python-workers-examples/01-hello

• Learn more about the basics of Python Workers
• Learn details about local development, deployment, and how to Python Workers work.
• Explore the package docs for instructions on how to use packages with Python Workers.
• Understand which parts of the Python Standard Library are supported in Python Workers.
• Learn about Python Workers' foreign function interface (FFI), and how to use it to work with bindings and Runtime APIs.