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

- Speed: Thanks to its Just-in-Time compiler, Python programs often run faster on PyPy
- Memory usage: large, memory-hungry Python programs might end up
taking less space than they do in CPython
- Compatibility: PyPy is highly compatible with existing python code.
It supports ctypes 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 can be configured to run in stackless mode,
providing micro-threads for massive concurrency