Best Tools to Convert Python to JavaScript and Vice Versa


This article provides information on the best tools that convert python to JavaScript. Some of the popular options covered include Brython, Transcrypt, Skulpt, Pyodide, PyJS, and Anvil. We will also look at JavaScript to Python converters like JS2Py.

8 min read
Updated: Nov 13, 2021

Alright, so why would anyone want Python to JavaScript converter in the first place. Well, there are many reasons including lack of JavaScript skill set, need to reuse existing python libraries, ability to code Python in the browser, and more.

For anyone new to programming, it is important to know that browsers natively understand only one scripting language and that is JavaScript. If you want to make browser-based applications, apply form validations, create dynamic web pages, then you need JavaScript.

You can execute JavaScript on the backend as well by utilizing the node js server which runs on the V8 engine. The V8 engine is the same engine that powers the Chrome browser.

Python to JavaScript Converter: What are the options

There are many options out there that allow you to mix and match Python and Javascript, let us start off with the mighty Brython –

Also on – Tools for Python and C interoperability

Brython – Python to JavaScript

Brython is the most popular option that allows you to utilize python as a scripting language for web development. From a python developer perspective, Brython supports Python 3 specifications and can be used as a JavaScript alternative to develop browser-based as well as server-side applications.

Brython includes ready-to-use libraries that allow you to interact with DOM elements and events. Brython also allows you to utilize existing JavaScript, HTML5, and CSS3 libraries like D3 charts, jQuery, SASS CSS, and Bootstrap.

Brython is growing in popularity and is currently under heavy development. To try your hands on with Brython, all you need to do is include the below on the webpage.

<script type="text/javascript" src="brython.js"></script>
<script type="text/javascript" src="brython_stdlib.js"></script>

Above gives you access to the latest development version, check out the Brython official website (link below) to pick the stable version that can be used in production. You can also include Brython from a couple of CDN options given in the Brython documentation.

How does it Work?

Brython itself is a JavaScript package that understands Python as well as JavaScript specifications. This allows you to include JavaScript libraries like D3 in your code and let you write python scripts to access functions from included libraries. You can also include existing Python libraries in your python scripts.  


Transcrypt – Python and JavaScript

Transcrypt is the mighty new kid on the block. Transcrypt precompiles Python to minified (optional) JavaScript that can be run in the browser or on the backend node server.

Like Brython, you can utilize existing JavaScript libraries while writing Python programs and everything clubbed together is precompiled to JavaScript by the Transcrypt.

Why use Transcrypt –

  • Capable to run on node Js.
  • Allows use of features like async/await, decorators, inheritance, operator overloading etc.
  • Compiles to JavaScript 6 code with call caching and loop optimizations.
  • Free to use, great documentation and growing community.

Developers can also use integrated sourcemaps to directly debug the python source code instead of looking into the compiled JavaScript.



Pyodide is among the most maintained and updated projects and compiles Python to WebAssembly. Pyodide provides a Python runtime environment in the browser and includes most of the scientific python libraries like scikit-learn, SciPy, Matplotlib, Pandas, and NumPy out of the box.

Though the inclusion of these libraries makes the overall code a bit heavy, the code executes fast since Pyodide uses direct Web APIs. Also, while Pyodide is batteries included when it comes to scientific development, you can still include other Python libraries from Pypi.

You may not want to call Pyodide a Python to JavaScript converter, but it does the job and provides an online Python runtime environment.


Skulpt – In Browser Python development

Skulpt provides you with a Python development environment in the browser itself eliminating the need to install and set up Python on your computer.

The Skulpt online Python editor is a perfect option for Python students and beginners, and for that reason, many trainers utilize Skulpt to provide Python training to beginners.

Skulpt was an experimental project of graham Scott but fast grew in popularity. As of today, many popular projects like Trinket, Runestone, CodeSkulptor, and anvil utilize the Skulpt engine to provide an online Python coding environment.

Skulpt is fast since it doesn’t make any calls to the server to interpret Python, the core JS engine is loaded in the browser and converts python code into JavaScript on the fly. You need to be aware that Python libraries that are not written purely in Python wouldn’t work with Skulpt, an example is NumPy.


PScript is an interesting project and allows you to write JavaScript using Python syntax. Well, what? Yes, you write JavaScript code as per python syntax and it works as JavaScript.

PScript is also valid Python and hence can be used as Python or PScript code which is further converted to the raw JavaScript. You also get the option to include raw JavaScript in your code by using the rawJS function provided by PScript. The references to the rawJS are kept and executed from the generated JavaScript.



Anvil is a commercial project and provides the capability to develop full-stack applications using just Python. It is more like an online integrated development environment and offers drag and drop functionality along with Python scripting.

You can build fully functional web applications without knowing much about HTML or JavaScript but only Python, under the hood it acts like a Python to JavaScript converter. Anvil provides the below features –

  • Drag and drop user interface to build web components
  • Option to write client-side Python Script for dynamic web pages and form validations
  • Option to write Server-side Python code to execute and serve HTTP requests
  • Data Tables as built-in database
  • Capability to include existing python libraries

Apart from the above, Anvil also provides one-click hosting, emails management, integration with third-party services like Stripe payments, Facebook, google apps, and more.



PyJS is a rich application development platform and was built by porting Google Web Toolkit widgets. It can be used to develop both web and desktop-based applications using pure Python. PyJS includes a python compiler, Ajax, and API-powered widgets.

While PyJS concept and project was a great idea, it is a dying project now without any significant development over the last few years.


JavaScript to Python Converter

Let us look at the other way round where you convert JavaScript to Python either online or by using a node or python-based translator.


Js2Py is the most effective tool to convert JavaScript to Python code and is written purely in Python itself. Being pure-play Python, it is easy to install and setup for Python developers. JS2PY provides interoperability of python and JavaScript code and lets you evaluate JavaScript variables from Python and utilize python objects from JavaScript.

All in all, you can mix both python and JS code and include python libraries as well as node js modules in the code, and compile it all to Python in the end.

For now, ECMA 5 is supported out of the box whereas ECMA 6 can be converted to Python in 2 steps. Convert ECMA 6 to ECMA5 using Babel transpilers and then you know the next step.


JSPyBridge – Python JavaScript Interoperability

JSPyBridge provides the option to interoperate Python and node js. If you are a python developer and need to use node js modules, you can do so by pip installing the JavaScript package in the python project. The reverse can be achieved by npm installing pythonia package on the node.

You can operate on objects of JavaScript from python and vice versa since JSPyBridge provides real interop support. Some of the key features are as listed below –

  • Provides bidirectional call-back support including the use of arbitrary arguments
  • Garbage collection out of the box
  • Exception handling support async and sync functions interoperability
  • And much more.

JSPyBridge is also under development and should be used with care for production use.


There are a few other useful options like PyV8 which provides support for the V8 JavaScript engine in Python itself, essentially a python wrapper for the V8 engine.

Closing Thoughts

It is evident that there are many options available to convert JavaScript to Python and back, and every option brings in many different features.

A Python trainer or course creator might go for Skulpt, a full stack Python developer might pay for Anvil, a frontend developer might like Brython more than all other options. It is important to pick the right tool for your use case to get the maximum efficiency and benefits.

This brings us to the end of Python to JavaScript transpilers analysis, hope you liked the article. If so, do share on social media with your friends.

Further reading – Python IDE Mac, Windows and Linux


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