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Minimal, modern embedded V8 for Python.

Project description

Minimal, modern embedded V8 for Python.

  • Free software: ISC license


  • Unicode support
  • Thread safe
  • Re-usable contexts
  • Binary object is Python agnostic

MiniRacer can be easily used by Django or Flask projects to minify assets, run babel or compile CoffeeScript.


py_mini_racer is straightforward to use:

>>> from py_mini_racer import py_mini_racer
>>> ctx = py_mini_racer.MiniRacer()
>>> ctx.eval('1+1')
>>> ctx.eval("var x = {company: 'Sqreen'};")
>>> print ctx.eval(u"'\N{HEAVY BLACK HEART}'")

>>> ctx.eval("var fun = () => ({ foo: 1 });")
{u'foo': 1}

Variables are kept inside of a context:

>>> ctx.eval("")
[1,2,3].map(n => n + 1);


PyMiniRacer is only compatible with Python 2.7 at the moment. Python 3 support is on its way.

Binary builds availability

The PyMiniRacer binary builds have been tested on x86_64 with:

  • OSX 10.11
  • Ubuntu >= 14.04
  • Debian >= 8
  • CentOS >= 7

You need pip >= 8.1 to install the wheels - you can check and upgrade yours in this way:

$ pip --version
$ pip install --upgrade pip

It should work on any Linux with a libc >= 2.17 and a wheel compatible pip (>= 8.1).

If you have a up-to-date pip and it doesn’t use a wheel, you might have an environment for which no wheel is built. Please open an issue.


We built Python wheels (prebuilt binaries) for OSX 64 bits and Linux 64 bits - most recent distributions. You need pip >= 1.4 and setuptools >= 0.8.

$ pip install py-mini-racer


You can build v8 with the command:

$ python build_v8

You can also build the ctype extension:

$ python build_ext

Which automatically builds v8.

You can generate a wheel with the command:

$ python bdist_wheel

which builds v8, the extension, and generates a wheel.


If you want to run the tests, you need to build V8 first, then launch:

$ python test --addopts tests


Built with love by Sqreen.

PyMiniRacer launch was described in this blog post.

PyMiniRacer is inspired by mini_racer, built for the Ruby world by Sam Saffron.

Tools used in rendering this package:


Lower libc version needed. Export V8 version. Fix circular structures export.



0.1.7 (2016-10-04)

  • Improve general performances of the JS execution.
  • Add the possibility to build a different version of V8 (for example with debug symbols).
  • Fix a conflict that could happens between statically linked libraries and dynamic ones.

0.1.6 (2016-08-12)

  • Add error message when py_mini_racer sdist fails to build asking to update pip in order to download the pre-compiled wheel instead of the source distribution.

0.1.5 (2016-08-04)

  • Build py_mini_racer against a static Python. When built against a shared library python, it doesn’t work with a static Python.

0.1.4 (2016-08-04)

  • Ensure JSEvalException message is converted to unicode

0.1.3 (2016-08-04)

  • Fix extension loading for python3
  • Add a make target for building distributions (sdist + wheels)
  • Fix eval conversion for python 3

0.1.2 (2016-08-03)

  • Fix date support
  • Fix Dockerfile for generating python3 wheels

0.1.1 (2016-08-02)

  • Fix sdist distribution.

0.1.0 (2016-08-01)

  • First release on PyPI.

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