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wtf is batavia?

rkenmi/batavia — explained in plain English

Analysis updated 2026-07-18 · repo last pushed 2017-08-20

JavaScriptAudience · developerComplexity · 4/5DormantSetup · moderate

TL;DR

An early-alpha JavaScript engine that runs Python code directly inside the browser, no installation required.

Mindmap

mindmap
  root((repo))
    What it does
      Runs Python in browser
      Reimplements bytecode VM
      Bridges JS and Python
    Tech stack
      JavaScript
      Python
      Node.js
    Use cases
      Teach Python online
      Embed code playgrounds
      Build in-browser IDEs
    Audience
      Educators
      Web developers

Code map

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filefunction / class

Why would anyone build with this?

REASON 1

Let students write and run Python in the browser with no local install.

REASON 2

Embed a Python sandbox into a documentation site or tutorial page.

REASON 3

Build an in-browser IDE or educational coding platform.

REASON 4

Bridge Python code with JavaScript objects already on the page.

What's in the stack?

JavaScriptPythonNode.js

How it stacks up

rkenmi/batavia3rd-eden/ircb.ioa15n/a15n
LanguageJavaScriptJavaScriptJavaScript
Last pushed2017-08-202016-11-162019-04-07
MaintenanceDormantDormantDormant
Setup difficultymoderateeasyeasy
Complexity4/52/52/5
Audiencedeveloperdevelopergeneral

Figures from each repo's GitHub metadata at analysis time.

How do you spin it up?

Difficulty · moderate Time to first run · 1h+

Early alpha, best for learning projects, not production use, needs Python 3.4/3.5 and Node.js to build.

Wtf does this do

Batavia lets you run Python code directly in your web browser using JavaScript. Instead of needing Python installed on a user's computer, you can write Python, and it will execute in the browser just like it would on your machine. This means educators can teach Python without asking students to install anything, and developers can embed Python playgrounds or interactive tutorials into websites. Here's how it works at a high level: Python code gets compiled into bytecode (a lower-level instruction set that Python's engine normally reads). Batavia recreates that same engine, but in JavaScript instead of C. When you write Python code in the browser, it gets converted to bytecode, then Batavia's JavaScript engine reads and executes those instructions, giving you back the results. It supports Python 3.4+ syntax and can even interact with JavaScript objects already running on the page, bridging the two languages together. Who would use this? Educators building interactive coding tutorials or online courses could let students write and run Python without setup friction. Web developers might embed a Python sandbox into their site for demos or documentation. Anyone building an in-browser IDE or educational platform that needs Python support would find this useful. Since Batavia is still in early development (the README calls it "early alpha"), it's best suited for learning projects and experimental work rather than mission-critical applications. The project is built with both Python and Node.js working together, Python code gets compiled down to bytecode, while JavaScript handles the virtual machine that interprets it. You need Python 3.4 or 3.5 and Node.js installed locally to build and develop on it. Once compiled, the result runs entirely in the browser with no server-side Python required.

Yoink these prompts

Prompt 1
Explain how Batavia compiles Python to bytecode and runs it with a JavaScript virtual machine.
Prompt 2
Help me set up a minimal Python playground in the browser using Batavia.
Prompt 3
How does Batavia let Python code interact with JavaScript objects on the same page?
Prompt 4
What are the current limitations of Batavia since it's still early alpha?

Frequently asked questions

wtf is batavia?

An early-alpha JavaScript engine that runs Python code directly inside the browser, no installation required.

What language is batavia written in?

Mainly JavaScript. The stack also includes JavaScript, Python, Node.js.

Is batavia actively maintained?

Dormant — no commits in 2+ years (last push 2017-08-20).

How hard is batavia to set up?

Setup difficulty is rated moderate, with roughly 1h+ to a first successful run.

Who is batavia for?

Mainly developer.

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