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PyPy vs Python: catalog facts
PyPy	Python
Free Free and open source under the MIT licence.	Free Free and open source under the Python Software Foundation Licence, a permissive licence.
Windows, macOS, Linux, Command line	Windows, macOS, Linux, Command line
JIT compiler speeds up many pure-Python workloads Can use less memory than CPython for large programs	Readable syntax that makes it the usual first language and easy to return to The standard library covers a lot without any third-party packages
C extensions such as NumPy run through a compatibility layer rather than natively Tracks newer Python versions behind CPython	Much slower than compiled languages for CPU-heavy work The global interpreter lock limits threading, though recent versions are addressing it
Downloadable app	Downloadable app
Open source	Open source
License: MIT	License: Python-2.0
No account needed	No account needed
Works offline	Works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked September 21, 2026

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