The pyzstd library was created by Ma Lin in 2020 to provide Python support for Zstandard, using an API style similar to the bz2, lzma, and zlib modules.

In 2025, an effort led by Emma Smith (now a CPython core developer) resulted in PEP 784 and the inclusion of the compression.zstd module in the Python 3.14 standard library. The implementation was adapted from pyzstd, with its maintainer Rogdham contributing directly to the effort. Rogdham also developed the backports.zstd library which backports the compression.zstd APIs to older Python versions.

In version 0.19.0, pyzstd became a pure-Python package by using the compression.zstd module internally.

Recommendations:

• New projects: use the standard library compression.zstd module, with backports.zstd as a fallback for older Python versions.

• Existing projects: consider migrating to the standard library implementation.

In the meanwhile, documentation for the pyzstd module is available here.