flit-core

Distribution-building parts of Flit. See flit package for more information

flit-core Permissive license BSD-3-Clause Active ★ 2,252 v4.0.2 released 2026-08-04

Install

flit-core on PyPI

pip

pip install flit-core

uv

uv add flit-core

poetry

poetry add flit-core

Package facts

License	BSD-3-Clause (permissive)
Python support	supports the current Python release (>=3.8)
Install friction	low — pure-Python wheel
Runtime dependencies	none
Maintenance	actively maintained — 9 days since the last release
Last repo commit	2026-08-11
First released	2019-11-17
Popularity	one of the top 1,000 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: flit_core-4.0.2-py3-none-any.whl

Topic :: Software Development :: Libraries :: Python Modules

About flit-core

from the package's own PyPI description — quoted content, verbatim

Flit is a simple way to put Python packages and modules on PyPI. It tries to require less thought about packaging and help you avoid common mistakes. See Why use Flit? <https://flit.readthedocs.io/en/latest/rationale.html>_ for more about how it compares to other Python packaging tools.

Install

$ python3 -m pip install flit

Flit requires Python 3 and therefore needs to be installed using the Python 3 version of pip.

Python 2 modules can be distributed using Flit, but need to be importable on Python 3 without errors.

Usage

Say you're writing a module foobar — either as a single file foobar.py, or as a directory — and you want to distribute it.

Make sure that foobar's docstring starts with a one-line summary of what the module is, and that it has a __version__:

.. code-block:: python

   """An amazing sample package!"""

   __version__ = "0.1"

Install flit if you don't already have it::

python3 -m pip install flit
Run flit init in the directory containing the module to create a pyproject.toml file. It will look something like this:

.. code-block:: ini

   [build-system]...

Read as markdown · JSON record · Source repository · Docs

AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

flit-core provides the build backend for Flit, a Python packaging tool that simplifies creating and publishing packages to PyPI by extracting metadata from module docstrings and version attributes.

Installation is frictionless with no runtime dependencies and a pure-wheel distribution. The project is actively maintained with a release 9 days ago and strong community adoption in the top 1000 PyPI packages.

BSD-3-Clause is a permissive license allowing commercial use, modification, and distribution with minimal restrictions, making flit-core suitable for both open-source and proprietary projects.

Usage

[build-system]
requires = ["flit_core >=3.2,<4"]
build-backend = "flit_core.buildapi"

Requires Python 3.8 or later; flit-core is a build-time dependency, not a runtime one.

Verdict: flit-core is a lightweight, actively maintained build backend with zero runtime dependencies, permissive licensing, and no known vulnerabilities. It is well-suited for developers seeking a straightforward packaging solution backed by strong community adoption.

Needs verification

Whether flit-core's build performance scales well for large monorepos or complex dependency trees
Compatibility with non-standard Python distributions beyond CPython

python package build backendflit build systempyproject.toml build toolpython packaging automationsimple python package publishingmetadata extraction from docstringsflit core distribution