Python in the browser - CPython compiled with emscripten
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Python in the browser

The aim of this project is to make Python usable in the browser. This is done using the standard Python implementation (CPython) compiled with emscripten to generate an asm.js library.

The benefits of this approach are:

  • This gives access to a full Python implementation.
  • Asm.js can be pretty fast, so the interpreter is still quite useful.
  • It supports existing extension modules.
  • It supports Cython for speeding up the code and binding to C/C++.

If you have a Python application using SDL (1 or 2) and maybe OpenGLES 2 then this project could help you deliver it via the browser.


The build requires a complete development toolchain for the build system. This is used to build the portions of Python required for bootstrapping the complete Python build.

Emscripten is also required for the cross compilation. Version 1.36.0 has been tested.

Some of the examples use Cython which can be installed with pip. Versions 0.20.1 and above have been used successfully.


Many of the patches and instructions are derived from the excellent work of Marat Dukhan on the EmCPython project.

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