Trove classifiers

PyPI and distutils provide a solution for categorizing applications with the set of classifiers called trove classifiers. All trove classifiers form a tree-like structure. Each classifier string defines a list of nested namespaces where every namespace is separated by the :: substring. Their list is provided to the package definition as a classifiers argument of the setup() function.

Here is an example list of classifiers taken from solrq project available on PyPI:

from setuptools import setup 
 
setup( 
    name="solrq", 
    # (...) 
 
    classifiers=[ 
        'Development Status :: 4 - Beta', 
        'Intended Audience :: Developers', 
        'License :: OSI Approved :: BSD License', 
        'Operating System :: OS Independent', 
        'Programming Language :: Python', 
        'Programming Language :: Python :: 2', 
        'Programming Language :: Python :: 2.6', 
        'Programming Language :: Python :: 2.7', 
        'Programming Language :: Python :: 3', 
        'Programming Language :: Python :: 3.2', 
        'Programming Language :: Python :: 3.3', 
        'Programming Language :: Python :: 3.4', 
        'Programming Language :: Python :: Implementation :: PyPy', 
        'Topic :: Internet :: WWW/HTTP :: Indexing/Search', 
    ], 
)

Trove classifiers are completely optional in the package definition but provide a useful extension to the basic metadata available in the setup() interface. Among others, trove classifiers may provide information about supported Python versions, supported operating systems, the development stage of the project, or the license under which the code is released. Many PyPI users search and browse the available packages by categories so a proper classification helps packages to reach their target.

Trove classifiers serve an important role in the whole packaging ecosystem and should never be ignored. There is no organization that verifies packages classification, so it is your responsibility to provide proper classifiers for your packages and not introduce chaos to the whole package index.

At the time of writing this book, there are 667 classifiers available on PyPI that are grouped into the following nine major categories:

This list is ever-growing, and new classifiers are added from time to time. It is thus possible that the total count of them will be different at the time you read this. The full list of currently available trove classifiers is available at https://pypi.org/classifiers/.