A Javascript implementation of the Python virtual machine.
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Latest commit a5493cd Jan 9, 2017 @freakboy3742 freakboy3742 committed on GitHub Merge pull request #409 from kennethlove/fix/string_startswith
Tests for str.startswith




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Batavia is an early alpha project. If it breaks, you get to keep all the shiny pieces.

Batavia is an implementation of the Python virtual machine, written in Javascript. With Batavia, you can run Python bytecode in your browser.

It honors Python 3.4.4+ syntax and conventions, and allows you to reference objects and classes defined natively in JavaScript.

Quick Start


Batavia requires a Python 3.4 installation, and a virtualenv to run it all in.

Check the Setting up your environment for configuration help.

Downloading and Installing

  1. Clone the code repositories:

    $ mkdir pybee
    $ cd pybee
    $ git clone https://github.com/pybee/batavia
  2. Setup a virtualenv (for other environments, see Getting Started).


$ virtualenv --python=$(which python3) venv
$ . venv/bin/activate
$ cd batavia
$ pip install -e .


> virtualenv venv
> venv\Scripts\activate
> cd batavia
> pip install -e .
  1. Install Node.js. You must have a recent version of Node; we do our testing using v6.9.1. Once you've installed Node, you can use it to install the Javascript dependencies and compile the Batavia library:

    $ npm install
  2. Compile the Batavia library and bundle it’s dependencies:

    $ npm run build

For more detailed setup instructions, see the Getting Started tutorial

Running Batavia in the browser

After you have setup the local installation of Batavia, you can now run Python in the browser:

$ cd testserver
$ pip install -r requirements.txt
$ ./manage.py runserver

then open a web browser at http://localhost:8000

For more detailed instructions, see the Python In The Browser guide.


Documentation for Batavia can be found on on Read The Docs, including:


If you'd like to contribute to Batavia development, our guide for first time contributors will help you get started.

If you experience problems with Batavia, log them on GitHub.


Batavia is part of the BeeWare suite. You can talk to the community through:

We foster a welcoming and respectful community as described in our BeeWare Community Code of Conduct.