---
id: ufmt
version: "2.9.1"
license: unclear
license_treatment: permissive
maintenance: active
---

# ufmt — Safe, atomic formatting with black and µsort

License: permissive · Maintenance: active · Downloads: 2.3M/mo

## What it is and what it does

ufmt is a Python code formatter that wraps black and µsort, running both tools in a single atomic operation. It formats files in-memory, first with µsort and then with black, before writing changes back to disk. This design prevents conflicts or intermediate states that can occur when running these tools separately in CI/CD pipelines.

The package is built for developers who want consistent, minimal diffs and safe handling without the risk of competing tools making conflicting changes. It integrates with GitHub Actions, pre-commit hooks, and Visual Studio Code, and supports checking, formatting, and diff-generation modes for different workflow needs.

Use it for:

- Enforce consistent Python formatting in CI/CD without conflicts between separate formatting steps.
- Set up pre-commit hooks to automatically format code before commits with atomic changes.
- Validate that files are properly formatted in pull requests using the check or diff modes.
- Use as the default formatter in VS Code for automatic formatting on save.
- Pin transitive dependencies in requirements files to ensure reproducible formatting across environments.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

ufmt combines black and µsort into a single atomic formatting pass, sorting imports and then formatting code in one operation before writing to disk.

Yes. ufmt solves a real problem—atomic, conflict-free formatting in CI workflows—with low install friction, active maintenance, no known vulnerabilities, and a permissive license. It is well-integrated into common development tools and suitable for teams that want safe, predictable formatting.

## Install

pip install ufmt
uv add ufmt
poetry add ufmt

## Installing ufmt

Before you install: Low friction: pure Python wheel with 8 runtime dependencies (black, click, libcst, moreorless, tomlkit, trailrunner, typing-extensions, usort). Active maintenance with recent commits; last release 187 days ago. Requires Python 3.10 or newer.

License in practice: MIT license (permissive). No restrictions on commercial or private use; you may modify and distribute freely with attribution.

Quickstart:

pip install ufmt
ufmt format myfile.py
ufmt check myfile.py
ufmt diff myfile.py

Requires Python 3.10 or newer.

Verify before relying:

- Whether pinning transitive dependencies (black, µsort) is necessary in practice to prevent unexpected formatting changes in CI workflows.
- Performance characteristics when formatting large codebases or many files at once.

## Package facts

- License: not declared (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 2.3M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

python code formatter with import sorting, atomic black and usort formatting, safe import sorter and code formatter, combined black µsort formatter, python formatter ci/cd workflow, prevent formatting conflicts formatter, in-memory formatting python, code-formatting, ci-cd

[View on SkillFed](https://skillfed.io/packages/ufmt) · [View on PyPI](https://pypi.org/project/ufmt/)