Command-line configuration

Mypy can be configured using command-line flags in addition to configuration files. Command-line flags have higher precedence than configuration file options (except for inline configuration).

Basic usage

mypy program.py
mypy package/
mypy -m mymodule
mypy -p mypackage

Specifying code to check

files

positional arguments

Files, directories, modules, or packages to type check.

mypy file1.py file2.py
mypy src/

-m MODULE

string

Type check a module by name.

mypy -m myapp.main

-p PACKAGE

string

Type check a package and all its submodules.

mypy -p mypackage

-c PROGRAM_TEXT

string

Type check a program passed as a string.

mypy -c "print('Hello, typed world!')"

Configuration file

--config-file CONFIG_FILE

string

Specify a configuration file to use.

mypy --config-file mypy-strict.ini src/

This flag has the highest precedence and must point to a valid configuration file.

--warn-unused-configs

boolean

Warn about unused [mypy-<pattern>] config file sections.

mypy --warn-unused-configs src/

Python version and platform

--python-version VERSION

string

default:"Current Python version"

Specify the Python version to target. Format: MAJOR.MINOR.

mypy --python-version 3.10 src/

Use this to check code compatibility with different Python versions.

--platform PLATFORM

string

default:"Current platform"

Specify the platform to check against (e.g., linux, darwin, win32).

mypy --platform win32 src/

--always-true NAME

string

Variables to treat as compile-time constants that are always true.

mypy --always-true DEBUG src/

--always-false NAME

string

Variables to treat as compile-time constants that are always false.

mypy --always-false TYPING_ONLY src/

Import discovery

--ignore-missing-imports

boolean

Suppress error messages about imports that cannot be resolved.

mypy --ignore-missing-imports src/

This is a blunt instrument. Consider using per-module configuration instead.

--follow-imports {normal,silent,skip,error}

choice

default:"normal"

How to handle imports:

normal: Follow imports and type check them
silent: Follow imports but suppress errors
skip: Don’t follow imports (treat as Any)
error: Treat imports as errors

mypy --follow-imports skip src/

--python-executable EXECUTABLE

string

Python executable to use for finding PEP 561 packages.

mypy --python-executable /usr/bin/python3.11 src/

--no-site-packages

boolean

Do not search for installed PEP 561 packages.

mypy --no-site-packages src/

--no-silence-site-packages

boolean

Report errors in installed packages.

mypy --no-silence-site-packages src/

Disallow dynamic typing

--disallow-any-unimported

boolean

Disallow Any types from unfollowed imports.

mypy --disallow-any-unimported src/

--disallow-any-expr

boolean

Disallow all expressions that have type Any.

mypy --disallow-any-expr src/

--disallow-any-decorated

boolean

Disallow functions with Any in signature after decorator transformation.

mypy --disallow-any-decorated src/

--disallow-any-explicit

boolean

Disallow explicit Any in type positions.

mypy --disallow-any-explicit src/

--disallow-any-generics

boolean

Disallow generic types without explicit type parameters.

mypy --disallow-any-generics src/

--disallow-subclassing-any

boolean

Disallow subclassing values of type Any.

mypy --disallow-subclassing-any src/

Untyped definitions and calls

--disallow-untyped-calls

boolean

Disallow calling untyped functions from typed functions.

mypy --disallow-untyped-calls src/

--untyped-calls-exclude MODULE

string

Exclude specific packages/modules from --disallow-untyped-calls.

mypy --disallow-untyped-calls --untyped-calls-exclude=third_party src/

--disallow-untyped-defs

boolean

Disallow defining functions without type annotations.

mypy --disallow-untyped-defs src/

--disallow-incomplete-defs

boolean

Disallow defining functions with incomplete type annotations.

mypy --disallow-incomplete-defs src/

--check-untyped-defs

boolean

Type check the interior of functions without type annotations.

mypy --check-untyped-defs src/

--disallow-untyped-decorators

boolean

Disallow decorating typed functions with untyped decorators.

mypy --disallow-untyped-decorators src/

None and Optional handling

--strict-optional

boolean

default:"True"

Enable strict checking of optional types and None values.

mypy --strict-optional src/

--no-strict-optional

boolean

Disable strict optional checking.

mypy --no-strict-optional src/

Not recommended. This makes None compatible with all types.

--implicit-optional

boolean

Treat arguments with None default as having optional type.

mypy --implicit-optional src/

Warnings

--warn-redundant-casts

boolean

Warn about redundant casts.

mypy --warn-redundant-casts src/

--warn-unused-ignores

boolean

Warn about unneeded # type: ignore comments.

mypy --warn-unused-ignores src/

--no-warn-no-return

boolean

Don’t warn about missing return statements.

mypy --no-warn-no-return src/

--warn-return-any

boolean

Warn when returning Any from non-Any function.

mypy --warn-return-any src/

--warn-unreachable

boolean

Warn about unreachable code.

mypy --warn-unreachable src/

Strictness flags

--strict

boolean

Enable all optional error checking flags.

mypy --strict src/

This is equivalent to enabling: --disallow-any-generics, --disallow-untyped-calls, --disallow-untyped-defs, --disallow-incomplete-defs, --check-untyped-defs, --disallow-untyped-decorators, --warn-redundant-casts, --warn-unused-ignores, --warn-return-any, --no-implicit-reexport, --strict-equality, --strict-concatenate, --extra-checks

--allow-untyped-globals

boolean

Suppress errors caused by not being able to infer types of global/class variables.

mypy --allow-untyped-globals src/

--allow-redefinition

boolean

Allow variable redefinition with arbitrary types.

mypy --allow-redefinition src/

--local-partial-types

boolean

Disallow partial types spanning module top level and function.

mypy --local-partial-types src/

--no-implicit-reexport

boolean

Require explicit re-export using from ... as ... or __all__.

mypy --no-implicit-reexport src/

--strict-equality

boolean

Prohibit equality/identity/container checks between non-overlapping types.

mypy --strict-equality src/

--extra-checks

boolean

Enable additional checks that are technically correct but impractical.

mypy --extra-checks src/

Error codes

--enable-error-code ERROR_CODE

string

Enable specific error codes.

mypy --enable-error-code truthy-bool,ignore-without-code src/

--disable-error-code ERROR_CODE

string

Disable specific error codes.

mypy --disable-error-code misc,no-untyped-def src/

Error message formatting

--show-error-context

boolean

Show context in error messages.

mypy --show-error-context src/

--show-column-numbers

boolean

Show column numbers in error messages.

mypy --show-column-numbers src/

--show-error-code-links

boolean

Show documentation links for error codes.

mypy --show-error-code-links src/

--hide-error-codes

boolean

Hide error codes in error messages.

mypy --hide-error-codes src/

--pretty

boolean

Use visually nicer output with soft word wrap and source snippets.

mypy --pretty src/

--no-color-output

boolean

Disable color in error messages.

mypy --no-color-output src/

--no-error-summary

boolean

Hide error summary.

mypy --no-error-summary src/

--show-absolute-path

boolean

Show absolute paths in error messages.

mypy --show-absolute-path src/

Incremental mode

--no-incremental

boolean

Disable incremental mode.

mypy --no-incremental src/

--cache-dir DIR

string

default:".mypy_cache"

Store cache info in the specified directory.

mypy --cache-dir /tmp/mypy_cache src/

--sqlite-cache

boolean

Use SQLite database for cache storage.

mypy --sqlite-cache src/

--cache-fine-grained

boolean

Include fine-grained dependencies in cache.

mypy --cache-fine-grained src/

--skip-version-check

boolean

Use cache even if generated by different Mypy version.

mypy --skip-version-check src/

--skip-cache-mtime-checks

boolean

Skip cache internal consistency checks based on mtime.

mypy --skip-cache-mtime-checks src/

Reports

Report generation disables incremental mode and slows down checking.

--any-exprs-report DIR

string

Generate a report of Any expressions.

mypy --any-exprs-report reports/ src/

--html-report DIR

string

Generate an HTML coverage report.

mypy --html-report htmlcov/ src/

--linecount-report DIR

string

Generate a line count report.

mypy --linecount-report reports/ src/

--linecoverage-report DIR

string

Generate a JSON line coverage report.

mypy --linecoverage-report reports/ src/

Advanced options

--plugins PLUGIN

string

Specify Mypy plugins to use.

mypy --plugins pydantic.mypy src/

--exclude PATTERN

string

Exclude files/directories matching the pattern.

mypy --exclude '/tests/' src/

--verbose

boolean

Show more verbose messages.

mypy --verbose src/

--pdb

boolean

Invoke debugger on fatal error.

mypy --pdb src/

--show-traceback

boolean

Show traceback on fatal error.

mypy --show-traceback src/

--raise-exceptions

boolean

Raise exceptions on fatal errors (for debugging).

mypy --raise-exceptions src/

Output options

--junit-xml FILE

string

Write a JUnit XML file with type checking results.

mypy --junit-xml junit.xml src/

--junit-format {global,per_file}

choice

default:"global"

Format for JUnit XML output.

mypy --junit-xml junit.xml --junit-format per_file src/

Combining flags

mypy --strict \
  --show-error-codes \
  --pretty \
  src/

Getting Started

Type System

Command Reference

Configuration

Guides

Advanced

Command-line configuration

Basic usage

Specifying code to check

Configuration file

Python version and platform

Import discovery

Disallow dynamic typing

Untyped definitions and calls

None and Optional handling

Warnings

Strictness flags

Error codes

Error message formatting

Incremental mode

Reports

Advanced options

Output options

Combining flags

Build docs developers (and LLMs) love

Getting Started

Type System

Command Reference

Configuration

Guides

Advanced

​Basic usage

​Specifying code to check

​Configuration file

​Python version and platform

​Import discovery

​Disallow dynamic typing

​Untyped definitions and calls

​None and Optional handling

​Warnings

​Strictness flags

​Error codes

​Error message formatting

​Incremental mode

​Reports

​Advanced options

​Output options

​Combining flags

Build docs developers (and LLMs) love

Basic usage

Specifying code to check

Configuration file

Python version and platform

Import discovery

Disallow dynamic typing

Untyped definitions and calls

None and Optional handling

Warnings

Strictness flags

Error codes

Error message formatting

Incremental mode

Reports

Advanced options

Output options

Combining flags