Configuring Ruff#

Ruff can be configured through a pyproject.toml, ruff.toml, or .ruff.toml file.

For a complete enumeration of the available configuration options, see Settings.

Using `pyproject.toml`#

If left unspecified, Ruff's default configuration is equivalent to:

[tool.ruff]
# Enable pycodestyle (`E`) and Pyflakes (`F`) codes by default.
select = ["E", "F"]
ignore = []

# Allow autofix for all enabled rules (when `--fix`) is provided.
fixable = ["A", "B", "C", "D", "E", "F", "G", "I", "N", "Q", "S", "T", "W", "ANN", "ARG", "BLE", "COM", "DJ", "DTZ", "EM", "ERA", "EXE", "FBT", "ICN", "INP", "ISC", "NPY", "PD", "PGH", "PIE", "PL", "PT", "PTH", "PYI", "RET", "RSE", "RUF", "SIM", "SLF", "TCH", "TID", "TRY", "UP", "YTT"]
unfixable = []

# Exclude a variety of commonly ignored directories.
exclude = [
    ".bzr",
    ".direnv",
    ".eggs",
    ".git",
    ".git-rewrite",
    ".hg",
    ".mypy_cache",
    ".nox",
    ".pants.d",
    ".pytype",
    ".ruff_cache",
    ".svn",
    ".tox",
    ".venv",
    "__pypackages__",
    "_build",
    "buck-out",
    "build",
    "dist",
    "node_modules",
    "venv",
]
per-file-ignores = {}

# Same as Black.
line-length = 88

# Allow unused variables when underscore-prefixed.
dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"

# Assume Python 3.10.
target-version = "py310"

[tool.ruff.mccabe]
# Unlike Flake8, default to a complexity level of 10.
max-complexity = 10

As an example, the following would configure Ruff to: (1) enforce flake8-bugbear rules, in addition to the defaults; (2) avoid enforcing line-length violations (E501); (3) avoid attempting to fix flake8-bugbear (B) violations; and (3) ignore import-at-top-of-file violations (E402) in __init__.py files:

[tool.ruff]
# Enable flake8-bugbear (`B`) rules.
select = ["E", "F", "B"]

# Never enforce `E501` (line length violations).
ignore = ["E501"]

# Avoid trying to fix flake8-bugbear (`B`) violations.
unfixable = ["B"]

# Ignore `E402` (import violations) in all `__init__.py` files, and in `path/to/file.py`.
[tool.ruff.per-file-ignores]
"__init__.py" = ["E402"]
"path/to/file.py" = ["E402"]

Plugin configurations should be expressed as subsections, e.g.:

[tool.ruff]
# Add "Q" to the list of enabled codes.
select = ["E", "F", "Q"]

[tool.ruff.flake8-quotes]
docstring-quotes = "double"

For a complete enumeration of the available configuration options, see Settings.

Ruff mirrors Flake8's rule code system, in which each rule code consists of a one-to-three letter prefix, followed by three digits (e.g., F401). The prefix indicates that "source" of the rule (e.g., F for Pyflakes, E for pycodestyle, ANN for flake8-annotations). The set of enabled rules is determined by the select and ignore options, which accept either the full code (e.g., F401) or the prefix (e.g., F).

As a special-case, Ruff also supports the ALL code, which enables all rules. Note that some pydocstyle rules conflict (e.g., D203 and D211) as they represent alternative docstring formats. Ruff will automatically disable any conflicting rules when ALL is enabled.

If you're wondering how to configure Ruff, here are some recommended guidelines:

Prefer select and ignore over extend-select and extend-ignore, to make your rule set explicit.
Use ALL with discretion. Enabling ALL will implicitly enable new rules whenever you upgrade.
Start with a small set of rules (select = ["E", "F"]) and add a category at-a-time. For example, you might consider expanding to select = ["E", "F", "B"] to enable the popular flake8-bugbear extension.
By default, Ruff's autofix is aggressive. If you find that it's too aggressive for your liking, consider turning off autofix for specific rules or categories (see FAQ).

Using `ruff.toml`#

As an alternative to pyproject.toml, Ruff will also respect a ruff.toml (or .ruff.toml) file, which implements an equivalent schema (though the [tool.ruff] hierarchy can be omitted).

For example, the pyproject.toml described above would be represented via the following ruff.toml (or .ruff.toml):

# Enable flake8-bugbear (`B`) rules.
select = ["E", "F", "B"]

# Never enforce `E501` (line length violations).
ignore = ["E501"]

# Avoid trying to fix flake8-bugbear (`B`) violations.
unfixable = ["B"]

# Ignore `E402` (import violations) in all `__init__.py` files, and in `path/to/file.py`.
[per-file-ignores]
"__init__.py" = ["E402"]
"path/to/file.py" = ["E402"]

For a complete enumeration of the available configuration options, see Settings.

Command-line interface#

Some configuration options can be provided via the command-line, such as those related to rule enablement and disablement, file discovery, logging level, and more:

ruff check path/to/code/ --select F401 --select F403 --quiet

See ruff help for more on Ruff's top-level commands:

Ruff: An extremely fast Python linter.

Usage: ruff [OPTIONS] <COMMAND>

Commands:
  check   Run Ruff on the given files or directories (default)
  rule    Explain a rule
  config  List or describe the available configuration options
  linter  List all supported upstream linters
  clean   Clear any caches in the current directory and any subdirectories
  help    Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Log levels:
  -v, --verbose  Enable verbose logging
  -q, --quiet    Print lint violations, but nothing else
  -s, --silent   Disable all logging (but still exit with status code "1" upon detecting lint violations)

For help with a specific command, see: `ruff help <command>`.

Or ruff help check for more on the linting command:

Run Ruff on the given files or directories (default)

Usage: ruff check [OPTIONS] [FILES]...

Arguments:
  [FILES]...  List of files or directories to check

Options:
      --fix
          Attempt to automatically fix lint violations
      --show-source
          Show violations with source code
      --show-fixes
          Show an enumeration of all autofixed lint violations
      --diff
          Avoid writing any fixed files back; instead, output a diff for each changed file to stdout. Implies `--fix-only`
  -w, --watch
          Run in watch mode by re-running whenever files change
      --fix-only
          Fix any fixable lint violations, but don't report on leftover violations. Implies `--fix`
      --ignore-noqa
          Ignore any `# noqa` comments
      --format <FORMAT>
          Output serialization format for violations [env: RUFF_FORMAT=] [possible values: text, json, junit, grouped, github, gitlab, pylint, azure]
      --target-version <TARGET_VERSION>
          The minimum Python version that should be supported [possible values: py37, py38, py39, py310, py311]
      --config <CONFIG>
          Path to the `pyproject.toml` or `ruff.toml` file to use for configuration
      --statistics
          Show counts for every rule with at least one violation
      --add-noqa
          Enable automatic additions of `noqa` directives to failing lines
      --show-files
          See the files Ruff will be run against with the current settings
      --show-settings
          See the settings Ruff will use to lint a given Python file
  -h, --help
          Print help

Rule selection:
      --select <RULE_CODE>
          Comma-separated list of rule codes to enable (or ALL, to enable all rules)
      --ignore <RULE_CODE>
          Comma-separated list of rule codes to disable
      --extend-select <RULE_CODE>
          Like --select, but adds additional rule codes on top of those already specified
      --per-file-ignores <PER_FILE_IGNORES>
          List of mappings from file pattern to code to exclude
      --extend-per-file-ignores <EXTEND_PER_FILE_IGNORES>
          Like `--per-file-ignores`, but adds additional ignores on top of those already specified
      --fixable <RULE_CODE>
          List of rule codes to treat as eligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
      --unfixable <RULE_CODE>
          List of rule codes to treat as ineligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
      --extend-fixable <RULE_CODE>
          Like --fixable, but adds additional rule codes on top of those already specified

File selection:
      --exclude <FILE_PATTERN>         List of paths, used to omit files and/or directories from analysis
      --extend-exclude <FILE_PATTERN>  Like --exclude, but adds additional files and directories on top of those already excluded
      --respect-gitignore              Respect file exclusions via `.gitignore` and other standard ignore files
      --force-exclude                  Enforce exclusions, even for paths passed to Ruff directly on the command-line

Miscellaneous:
  -n, --no-cache
          Disable cache reads
      --isolated
          Ignore all configuration files
      --cache-dir <CACHE_DIR>
          Path to the cache directory [env: RUFF_CACHE_DIR=]
      --stdin-filename <STDIN_FILENAME>
          The name of the file when passing it through stdin
  -e, --exit-zero
          Exit with status code "0", even upon detecting lint violations
      --exit-non-zero-on-fix
          Exit with a non-zero status code if any files were modified via autofix, even if no lint violations remain

Log levels:
  -v, --verbose  Enable verbose logging
  -q, --quiet    Print lint violations, but nothing else
  -s, --silent   Disable all logging (but still exit with status code "1" upon detecting lint violations)

`pyproject.toml` discovery#

Similar to ESLint, Ruff supports hierarchical configuration, such that the "closest" pyproject.toml file in the directory hierarchy is used for every individual file, with all paths in the pyproject.toml file (e.g., exclude globs, src paths) being resolved relative to the directory containing that pyproject.toml file.

There are a few exceptions to these rules:

In locating the "closest" pyproject.toml file for a given path, Ruff ignores any pyproject.toml files that lack a [tool.ruff] section.
If a configuration file is passed directly via --config, those settings are used for across files. Any relative paths in that configuration file (like exclude globs or src paths) are resolved relative to the current working directory.
If no pyproject.toml file is found in the filesystem hierarchy, Ruff will fall back to using a default configuration. If a user-specific configuration file exists at ${config_dir}/ruff/pyproject.toml, that file will be used instead of the default configuration, with ${config_dir} being determined via the dirs crate, and all relative paths being again resolved relative to the current working directory.
Any pyproject.toml-supported settings that are provided on the command-line (e.g., via --select) will override the settings in every resolved configuration file.

Unlike ESLint, Ruff does not merge settings across configuration files; instead, the "closest" configuration file is used, and any parent configuration files are ignored. In lieu of this implicit cascade, Ruff supports an extend field, which allows you to inherit the settings from another pyproject.toml file, like so:

# Extend the `pyproject.toml` file in the parent directory.
extend = "../pyproject.toml"
# But use a different line length.
line-length = 100

All of the above rules apply equivalently to ruff.toml and .ruff.toml files. If Ruff detects multiple configuration files in the same directory, the .ruff.toml file will take precedence over the ruff.toml file, and the ruff.toml file will take precedence over the pyproject.toml file.

Python file discovery#

When passed a path on the command-line, Ruff will automatically discover all Python files in that path, taking into account the exclude and extend-exclude settings in each directory's pyproject.toml file.

By default, Ruff will also skip any files that are omitted via .ignore, .gitignore, .git/info/exclude, and global gitignore files (see: respect-gitignore).

Files that are passed to ruff directly are always linted, regardless of the above criteria. For example, ruff check /path/to/excluded/file.py will always lint file.py.

Rule selection#

The set of enabled rules is controlled via the select and ignore settings, along with the extend-select and extend-ignore modifiers.

To resolve the enabled rule set, Ruff may need to reconcile select and ignore from a variety of sources, including the current pyproject.toml, any inherited pyproject.toml files, and the CLI (e.g., --select).

In those scenarios, Ruff uses the "highest-priority" select as the basis for the rule set, and then applies any extend-select, ignore, and extend-ignore adjustments. CLI options are given higher priority than pyproject.toml options, and the current pyproject.toml file is given higher priority than any inherited pyproject.toml files.

For example, given the following pyproject.toml file:

[tool.ruff]
select = ["E", "F"]
ignore = ["F401"]

Running ruff check --select F401 would result in Ruff enforcing F401, and no other rules.

Running ruff check --extend-select B would result in Ruff enforcing the E, F, and B rules, with the exception of F401.

Error suppression#

To omit a lint rule entirely, add it to the "ignore" list via ignore or extend-ignore, either on the command-line or in your pyproject.toml file.

To ignore a violation inline, Ruff uses a noqa system similar to Flake8. To ignore an individual violation, add # noqa: {code} to the end of the line, like so:

# Ignore F841.
x = 1  # noqa: F841

# Ignore E741 and F841.
i = 1  # noqa: E741, F841

# Ignore _all_ violations.
x = 1  # noqa

Note that, for multi-line strings, the noqa directive should come at the end of the string, and will apply to the entire string, like so:

"""Lorem ipsum dolor sit amet.

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor.
"""  # noqa: E501

To ignore all violations across an entire file, add # ruff: noqa to any line in the file, like so:

# ruff: noqa

To ignore a specific rule across an entire file, add # ruff: noqa: {code} to any line in the file, like so:

# ruff: noqa: F841

Or see the per-file-ignores configuration setting, which enables the same functionality via a pyproject.toml file.

Note that Ruff will also respect Flake8's # flake8: noqa directive, and will treat it as equivalent to # ruff: noqa.

Automatic `noqa` management#

Ruff supports several workflows to aid in noqa management.

First, Ruff provides a special rule code, RUF100, to enforce that your noqa directives are "valid", in that the violations they say they ignore are actually being triggered on that line (and thus suppressed). You can run ruff check /path/to/file.py --extend-select RUF100 to flag unused noqa directives.

Second, Ruff can automatically remove unused noqa directives via its autofix functionality. You can run ruff check /path/to/file.py --extend-select RUF100 --fix to automatically remove unused noqa directives.

Third, Ruff can automatically add noqa directives to all failing lines. This is useful when migrating a new codebase to Ruff. You can run ruff check /path/to/file.py --add-noqa to automatically add noqa directives to all failing lines, with the appropriate rule codes.

Action comments#

Ruff respects isort's action comments (# isort: skip_file, # isort: on, # isort: off, # isort: skip, and # isort: split), which enable selectively enabling and disabling import sorting for blocks of code and other inline configuration.

Ruff will also respect variants of these action comments with a # ruff: prefix (e.g., # ruff: isort: skip_file, # ruff: isort: on, and so on). These variants more clearly convey that the action comment is intended for Ruff, but are functionally equivalent to the isort variants.

See the isort documentation for more.

Exit codes#

By default, Ruff exits with the following status codes:

0 if no violations were found, or if all present violations were fixed automatically.
1 if violations were found.
2 if Ruff terminates abnormally due to invalid configuration, invalid CLI options, or an internal error.

This convention mirrors that of tools like ESLint, Prettier, and RuboCop.

Ruff supports two command-line flags that alter its exit code behavior:

--exit-zero will cause Ruff to exit with a status code of 0 even if violations were found. Note that Ruff will still exit with a status code of 2 if it terminates abnormally.
--exit-non-zero-on-fix will cause Ruff to exit with a status code of 1 if violations were found, even if all such violations were fixed automatically. Note that the use of --exit-non-zero-on-fix can result in a non-zero exit code even if no violations remain after autofixing.

Autocompletion#

Ruff supports autocompletion for most shells. A shell-specific completion script can be generated by ruff generate-shell-completion <SHELL>, where <SHELL> is one of bash, elvish, fig, fish, powershell, or zsh.

The exact steps required to enable autocompletion will vary by shell. For example instructions, see the Poetry or ripgrep documentation.

As an example: to enable autocompletion for Zsh, run ruff generate-shell-completion zsh > ~/.zfunc/_ruff. Then add the following line to your ~/.zshrc file, if they're not already present:

fpath+=~/.zfunc
autoload -Uz compinit && compinit

Configuring Ruff#

Using pyproject.toml#

Using ruff.toml#

Command-line interface#

pyproject.toml discovery#

Python file discovery#

Rule selection#

Error suppression#

Automatic noqa management#

Action comments#

Exit codes#

Autocompletion#

Using `pyproject.toml`#

Using `ruff.toml`#

`pyproject.toml` discovery#

Automatic `noqa` management#