PyPy3

PyPy3 is the Python 3 compatible implementation of the PyPy project, an alternative Python interpreter designed to be fast and memory efficient. Like PyPy overall, PyPy3 uses a just-in-time (JIT) compiler to accelerate Python code at runtime rather than relying solely on the interpreter. The project is implemented in RPython, a restricted subset of Python, and produces a self-contained executable that includes the runtime and the standard library.

A central feature of PyPy3 is its tracing JIT, which records hot paths during execution and compiles them to machine code on the fly. This approach often yields substantial speedups for pure Python workloads compared with the reference CPython implementation, while aiming to keep memory usage competitive. PyPy3 also implements its own garbage collection system, typically a generational collector, to manage memory efficiently in long-running processes.

Compatibility and extensions are important considerations. PyPy3 strives to be highly compatible with Python 3, but there can be gaps with some C extension modules. To support CPython extensions, PyPy provides a compatibility layer known as cpyext, though performance and behavior may vary compared with CPython. Most pure Python code runs under PyPy3 without modification, but certain libraries or extension modules may require testing or alternative implementations.

PyPy3 is distributed as prebuilt binaries for major platforms, including Linux, Windows, and macOS, and is available for installation through various package managers or direct downloads. While PyPy3 often delivers speed improvements for many Python workloads, results vary by workload, and warm-up time for the JIT can affect short-running tasks.