Welcome to PyPy

PyPy is a fast, compliant alternative implementation of the Python language (2.7.6 and 3.2.5). It has several advantages and distinct features:

  • Speed: thanks to its Just-in-Time compiler, Python programs often run faster on PyPy. (What is a JIT compiler?)
  • Memory usage: memory-hungry Python programs (several hundreds of MBs or more) might end up taking less space than they do in CPython.
  • Compatibility: PyPy is highly compatible with existing python code. It supports cffi and can run popular python libraries like twisted and django.
  • Sandboxing: PyPy provides the ability to run untrusted code in a fully secure way.
  • Stackless: PyPy comes by default with support for stackless mode, providing micro-threads for massive concurrency.
  • As well as other features.

Download and try out the PyPy or PyPy3 release 2.3.1!

Want to know more? A good place to start is our detailed speed and compatibility reports!