Ruff vs rustfmt

Ruff is a Python linter and code formatter written in Rust, available free under a permissive open-source license. It includes more than 900 built-in lint rules, including native versions of popular Flake8 plugin rules, and can automatically correct violations such as unused imports. Its formatter aims to serve as a replacement for Black, though the documentation allows for differences in some cases. The built-in Ruff Language Server supplies diagnostics, fixes, and formatting; the documentation recommends pairing it with another Python language server for navigation and autocompletion. Setup guidance covers VS Code, Sublime Text, PyCharm, and Zed, while CI support includes GitHub Actions, GitLab CI/CD, and pre-commit hooks. Ruff can be installed through uv, pip, pipx, standalone installers, Homebrew, Conda, and other package managers. It supports configuration in pyproject.toml, ruff.toml, or .ruff.toml. A Bandit-derived rule group checks for common Python security issues. Ruff runs on Linux, macOS, and Windows, and is also published as a Docker image. The maker describes it as 10–100x faster than tools such as Flake8 and Black.

rustfmt formats Rust code according to style guidelines. It can format files directly or read code from standard input and write formatted output to standard output. With Cargo, `cargo fmt` formats binary and library targets in a crate and works with workspaces. A `rustfmt.toml` or `.rustfmt.toml` file can hold configuration, including stable and nightly-only options. For automated checks, `--check` returns code 0 when no formatting changes are needed and code 1 when changes would be made; it can be used in CI to fail a build on formatting differences. The README lists editor use with Vim, Emacs, Sublime Text 3, Atom, Visual Studio Code, IntelliJ, and CLion. Rustfmt is available on Windows, macOS, and Linux, and is distributed under the MIT License and Apache License 2.0. It does not attempt to format comments, and listed limitations also involve macros, unparsable code, fragments, and non-ASCII Unicode. Unstable settings require opt-in on nightly, and the README says the latest version requires the nightly toolchain.