Configuration file location

Before running the linter, you need to supply configuration in a file. If not specified over the command line, Import Linter will look in the current directory for one of the following files:

  • setup.cfg (INI format)

  • .importlinter (INI format)

  • pyproject.toml (TOML format)

Top level configuration

Your file must contain an importlinter section providing top-level (i.e. non-contract based) configuration:

root_package = mypackage
# Optional:
include_external_packages = True
exclude_type_checking_imports = True

Or, with multiple root packages:

# Optional:
include_external_packages = True
exclude_type_checking_imports = True


  • root_package: The name of the Python package to validate. For regular packages, this must be the top level package (i.e. one with no dots in its name). However, in the special case of namespace packages, the name of the portion should be supplied, for example ''. This package must be importable: usually this means it is has been installed using pip, or it’s in the current directory. (Either this or root_packages is required.)

  • root_packages: The names of the Python packages to validate. This should be used in place of root_package if you want to analyse the imports of multiple packages, and is subject to the same requirements. (Either this or root_package is required.)

  • include_external_packages: Whether to include external packages when building the import graph. Unlike root packages, external packages are not statically analyzed, so no imports from external packages will be checked. However, imports of external packages will be available for checking. Not every contract type uses this. For more information, see the Grimp build_graph documentation. (Optional.)

  • exclude_type_checking_imports: Whether to exclude imports made in type checking guards. If this is True, any import made under an if TYPE_CHECKING: statement will not be added to the graph. For more information, see the Grimp build_graph documentation. (Optional.)


Additionally, you will want to include one or more contract configurations. These take the following form:

name = Contract One
type = some_contract_type
(additional options)

name = Contract Two
type = another_contract_type
(additional options)

Notice each contract has its own INI section, which begins importlinter:contract: and ends in a unique id (in this example, the ids are one and two). These codes can be used to to select individual contracts when running the linter (see below).

Every contract will always have the following key/value pairs:

  • name: A human-readable name for the contract.

  • type: The type of contract to use (see Contract types.)

Each contract type defines additional options that you supply here.

Running the linter

Import Linter provides a single command: lint-imports.

Running this will check that your project adheres to the contracts you’ve defined.


  • --config: The configuration file to use. This overrides the default file search strategy. By default it’s assumed that the file is an ini-file unless the file extension is toml. (Optional.)

  • --contract: Limit the check to the contract with the supplied id. In INI files, a contract’s id is the final part of the section header: for example, the id for a contract with a section header of [importlinter:contract:foo] is foo. In TOML files, ids are supplied explicitly with an id key. This option may be provided multiple times to check more than one contract. (Optional.)

  • --cache-dir: The directory to use for caching. Defaults to .import_linter_cache. See Caching. (Optional.)

  • --no-cache: Disable caching. See Caching. (Optional.)

  • --show_timings: Display the times taken to build the graph and check each contract. (Optional.)

  • --verbose: Noisily output progress as it goes along. (Optional.)

Default usage:


Using a different filename or location:

lint-imports --config path/to/alternative-config.ini

Checking only certain contracts:

lint-imports --contract some-contract --contract another-contract

Using a different cache directory, or disabling caching:

lint-imports --cache-dir path/to/cache

lint-imports --no-cache

Showing timings:

lint-imports --show-timings

Verbose mode:

lint-imports --verbose