ufmt
Safe, atomic formatting with black and µsort
Decision gist · record as of 2026-08-14
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.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or newer.
- 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.
License · maintenance · safety
permissive license (permissive) — MIT license (permissive). No restrictions on commercial or private use; you may modify and distribute freely with attribution.
last release 2026-02-08 (187 days) · last repo commit 2026-05-18 · 110 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 2,337,651 downloads/mo, #3,127 on PyPI
Alternatives
Verify before relying
pip install ufmt
ufmt format myfile.py
ufmt check myfile.py
ufmt diff myfile.py- 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.
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 on this page. Verify before relying on it.
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
ufmt on PyPI
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.
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.pyVerify 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 | permissive license permissive |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 8 packagesblackclicklibcstmoreorlesstomlkittrailrunnertyping-extensionsusort |
| Maintenance | Actively maintained 187 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 2,337,651 / month, #3,127 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseTopic :: UtilitiesTyping :: Typed |
Evidence: ufmt-2.9.1-py3-none-any.whl
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See also usort · black · darker · mdformat-black · sort-lines · docstrfmt · pyink · reformat-gherkin · mdformat-ruff · isort