Compatibility: PyPy is highly compatible with existing python code. It supports cffi, cppyy, and can run popular python libraries like twisted, and django. It can also run NumPy, Scikit-learn and more via a c …

Unlike other sandboxing approaches for Python, PyPy's does not try to limit language features considered "unsafe". Instead we replace all calls to external libraries (C or platform) with a stub that …

Dec 3, 2025 · What is PyPy? Historically, PyPy has been used to mean two things. The first is the RPython translation toolchain for generating interpreters for dynamic programming languages. And …

Dec 3, 2025 · Welcome to the documentation for PyPy, a fast, compliant alternative implementation of the Python language. If you want to find out more about what PyPy is, have a look at our What is …

Dec 3, 2025 · What is PyPy? PyPy is a reimplementation of Python in Python, using the RPython translation toolchain. PyPy tries to find new answers about ease of creation, flexibility, maintainability …

Source 3.11 Source (tar.bz2); 3.11 Source (zip). 2.7 Source (tar.bz2); 2.7 Source (zip). More information Visit the more information page for other platforms, information about running PyPy, STM, …

Dec 3, 2025 · The quickest way to start using PyPy is to download a prebuilt binary for your OS and architecture. You may be able to use either use the most recent release or one of our development …

The above is true both in CPython and in PyPy. Differences can occur about whether a built-in function or method will call an overridden method of another object than self. In PyPy, they are often called in …

PyPy supports C extension modules solely to provide basic functionality. If the extension module is for speedup purposes only, then it makes no sense to use it with PyPy at the moment.

The main difference in pure-python code that is not going to be fixed is that PyPy does not support refcounting semantics for "automatically" releasing state when an object's __del__ is called.