Simple list of top-level packages in Python’s stdlib

license version changelog documentation

This package provides a static listing of all known modules in the Python standard library, with separate lists available for each major release dating back to Python 2.3. It also includes combined lists of all module names that were ever available in any 3.x release, any 2.x release, or both.

Note: On Python versions 3.10 or newer, a list of module names for the active runtime is available sys.stdlib_module_names. This package exists to provide an historical record for use with static analysis and other tooling.

This package only includes listings for CPython releases. If other runtimes would be useful, open an issue and start a discussion on how best that can be accomodated.


You can install it from PyPI:

$ pip install stdlibs


The recommended usage is to reference stdlibs.module_names — the top-level names that are valid in some version of Python 3.x on some platform. This is a superset of top-level names you may have, and a superset of those in sys.stdlib_module_names.

>>> from stdlibs import module_names
>>> print("os" in module_names)
>>> print("peg_parser" in module_names)  # 3.9+

If you need a specific version, those are available as other modules:

>>> from stdlibs.py36 import module_names as module_names_py36
>>> print("os" in module_names_py36)
>>> print("peg_parser" in module_names_py36)

If you intend to process more than one version, you may find the string api easier:

>>> from stdlibs import stdlib_module_names, KNOWN_VERSIONS
>>> [v for v in KNOWN_VERSIONS if "dataclasses" in stdlib_module_names(v)]
['3.7', '3.8', '3.9', '3.10', '3.11']
>>> sorted(stdlib_module_names("3.7") - stdlib_module_names("3.6"))
['_abc', '_contextvars', '_py_abc', '_queue', '_uuid', '_xxtestfuzz', 'contextvars', 'dataclasses']
>>> from import unified_diff
>>> prev = None
>>> buf = []
>>> for v in KNOWN_VERSIONS:
...     cur = ''.join([f"{name}\n" for name in sorted(stdlib_module_names(v))])
...     if prev:
...         buf.append(unified_diff(prev, cur, f"new-in-{v}"))
...     prev = cur
>>> print(''.join(''.join(buf).splitlines(True)[:10]), end='')
--- a/new-in-2.4
+++ b/new-in-2.4
@@ -19,7 +19,6 @@


Add or update the list of releases and download URLs in stdlibs/, then execute the stdlibs.fetch module:

$ make distclean virtualenv
$ source .venv/bin/activate
(.venv) $ python -m stdlibs.fetch


stdlibs is copyright John Reese, and licensed under the MIT license. I am providing code in this repository to you under an open source license. This is my personal repository; the license you receive to my code is from me and not from my employer. See the LICENSE file for details.