mypy-extensions
Type system extensions for programs checked with the mypy type checker.
Decision gist · record as of 2026-08-14
Yes, if you use mypy for type checking. It is a lightweight, stable, production-ready library with no runtime dependencies and low install friction. The unclear license is a minor concern that should be resolved before use in proprietary contexts, but the package's widespread adoption (top 1000 on PyPI) and active maintenance suggest it is safe for most open-source and standard development workflows.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.8 or later.
- Low install friction with a pure-Python wheel distribution.
- Maintenance is aging—last release was 479 days ago, though the repository remains active with a recent commit on 2025-04-22 and no archived status.
License · maintenance · safety
(unclear) — License treatment is unclear; neither SPDX nor raw license metadata is available. Verify the actual license terms before adopting in proprietary or restricted contexts.
last release 2025-04-22 (479 days) · last repo commit 2025-04-22 · 154 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 317,045,593 downloads/mo, #131 on PyPI
Alternatives
Verify before relying
pip install mypy-extensions
from mypy_extensions import TypedDict
MyDict = TypedDict('MyDict', {'key': str, 'value': int})- Specific typing constructs and extensions provided beyond the standard library typing module.
- Whether mypyc compiler support is automatic or requires additional configuration.
- Current license classification and any restrictions on use or redistribution.
What it is and what it does
mypy_extensions is a small library that extends Python's standard typing module with additional type constructs recognized by the mypy static type checker and the mypyc compiler. It bridges the gap between what the standard library's typing module offers and what mypy needs to support advanced type-checking scenarios. The package has no runtime dependencies, making it lightweight to install and use.
Developers use it when they need type annotations or type-checking features that mypy supports but the standard library typing module does not yet provide. It is typically imported directly into type-annotated code or used as a development dependency in projects that rely on mypy for static analysis. The package supports Python 3.8 through 3.13 and is marked as Production/Stable.
Use it for
- Add mypy-specific type annotations to a codebase that uses mypy for static type checking.
- Use TypedDict and other extended typing constructs in projects that require mypy validation.
- Support mypyc compilation of Python code with advanced type annotations.
- Ensure type compatibility across different Python versions when using mypy.
- Extend type hints in libraries that need to remain compatible with mypy's type system.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you use mypy for type checking.
It is a lightweight, stable, production-ready library with no runtime dependencies and low install friction. The unclear license is a minor concern that should be resolved before use in proprietary contexts, but the package's widespread adoption (top 1000 on PyPI) and active maintenance suggest it is safe for most open-source and standard development workflows.
Install
mypy-extensions on PyPI
Before you install
Low install friction with a pure-Python wheel distribution. Maintenance is aging—last release was 479 days ago, though the repository remains active with a recent commit on 2025-04-22 and no archived status.
Requires Python 3.8 or later.
License in practice
License treatment is unclear; neither SPDX nor raw license metadata is available. Verify the actual license terms before adopting in proprietary or restricted contexts.
Quickstart
pip install mypy-extensions
from mypy_extensions import TypedDict
MyDict = TypedDict('MyDict', {'key': str, 'value': int})Verify before relying
- Specific typing constructs and extensions provided beyond the standard library typing module.
- Whether mypyc compiler support is automatic or requires additional configuration.
- Current license classification and any restrictions on use or redistribution.
Package facts
| License | Not declared unclear |
| Python support | Supports the current Python release >=3.8 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | None |
| Maintenance | Aging 479 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 317,045,593 / month, #131 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableEnvironment :: ConsoleIntended Audience :: DevelopersProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Topic :: Software Development |
Evidence: mypy_extensions-1.1.0-py3-none-any.whl
Tags
Let your AI agent find packages like this
Example. Real query, live index.
You found this page by searching. An agent finds it by wishing: SkillFed indexes 14,416 PyPI packages by what they can do, searchable in plain language.
wish › “mypy type extensions”
- mypy-extensionsProvides type system extensions for Python programs checked with…
- django-stubs-extProvides runtime monkey-patching extensions for django-stubs to…
- pybind11-stubgenGenerates PEP 561 type stubs for Python binary extensions, making…
Give your agent the search over MCP, or paste the wish link into any chat.
More Software Development packages
Provides backported and experimental type hints for Python 3.9+, allowing use of newer typing features on older Python versions and enabling early experimentation with type system PEPs before they enter the standard library.
NumPy provides an N-dimensional array object and a comprehensive suite of mathematical, linear algebra, Fourier transform, and random number functions for scientific computing in Python.
FastAPI is a Python web framework for building REST APIs using type hints, with automatic request validation, serialization, and interactive API documentation.
Provides a way to document function parameters, class attributes, return types, and variables inline using Python's `Annotated` type hint syntax instead of traditional docstrings.
Typer builds command-line applications from Python functions using type hints, automatically generating help text, argument parsing, and shell completion.
Install it if you are building CLIs in Python.
Distlib provides low-level packaging utilities for building, distributing, and managing Python software—including metadata handling, version specifiers, wheel support, script installation, and dependency resolution.
See also mypy · types-mypy-extensions · strongtyping · type-enforced · typing-inspect · librt · pyre-extensions · ast-serialize · optype · construct-typing