Black vs rustfmt
Black
black.readthedocs.iorustfmt
rust-lang.github.ioSide by side
| Figure | Black | rustfmt |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 1 | 1 |
| Spec score · Code Formatting Tools | 8.7 (#1) | 8.0 (#10) |
| Spec score · Code formatters | 8.7 (#1) | 7.9 (#4) |
| Editor integrations | The documentation describes integrations for editors including PyCharm, Vim, Neovim, Visual Studio Code, and Sublime Text. | The README lists integrations or usage instructions for Vim, Emacs, Sublime Text 3, Atom, Visual Studio Code, and IntelliJ or CLion. |
| License | Black is licensed under the MIT license. | rustfmt is distributed under both the MIT License and Apache License 2.0. |
| Purpose | Black is an opinionated formatter for Python code that follows PEP 8. | rustfmt formats Rust code according to style guidelines. |
| Style stability | For stable releases, code formatted with a release remains unchanged under other releases in the same calendar year when using the same options. | The Rust Edition Guide describes a formatting stability guarantee intended to avoid noisy formatting changes when updating the Rust toolchain. |
Plans
In their own words
Black
Black is a free, MIT-licensed formatter for Python code that follows PEP 8. It reformats whole files in place and uses a default line length of 88 characters. Its limited style choices are intended to keep code consistent across projects; indentation style cannot be configured. After formatting, Black checks whether the abstract syntax tree remains effectively equivalent and raises an error if the check fails. Install it with pip; it requires Python 3.10 or newer. The documentation lists editor integrations including Emacs, PyCharm, IntelliJ IDEA, Vim, Neovim, Visual Studio Code and Sublime Text, as well as GitHub Actions and doctest workflows. Notebook formatting is available with the jupyter extra, though Black skips cells containing certain magics or invalid syntax. It also includes blackd, an HTTP server that binds to localhost by default. Black is primarily a command-line tool and does not provide a Python interface. Stable releases preserve formatting within the same calendar year when the options match.
rustfmt
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.