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MyPy Review

MyPy is an optional static type checker for Python that helps ensure correct usage of variables and functions by adding type hints.

shipped Apr 2, 2026updated May 27, 2026aifreemium
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MyPy - AI tool for mypy. Professional illustration showing core functionality and features.

Why it matters

1MyPy leverages PEP 484 type hints to perform static analysis on Python code, identifying type-related errors before runtime.
2The tool supports gradual typing, allowing developers to incrementally add type annotations to existing Python codebases.
3Version 1.19.1 is the latest point release, with MyPy 1.19.0 introducing experimental support for PEP 747 (Annotating Type Forms).
4An experimental binary fixed-format cache, introduced in MyPy 1.18, is planned to be enabled by default in a future release (e.g., 1.20), aiming to make incremental builds up to twice as fast.

Stork’s verdict on MyPy

MyPy helps catch type-related bugs early for reliability, but it's largely overkill for smaller Python projects.

MyPy reviewed by Stork AI · stork.ai/en/mypy

Specs

API Docs

View Documentation →

GitHub

View Repository →

API Available

Yes, public API

overview

What is MyPy?

MyPy is a static type checker tool developed by the Python community that enables Python developers to ensure correct usage of variables and functions by adding type hints. It leverages type hints (PEP 484) to analyze Python programs and warn users about incorrect type usage before runtime. MyPy's primary function is to perform static type checking on Python code, analyzing it without execution to ensure variables and functions conform to their specified types. This process aids in early bug detection, reducing the need for extensive runtime debugging and testing in Python projects. The tool is under active development, with recent releases like MyPy 1.19.1 focusing on performance improvements, new typing features, and bug fixes.

features

Key Features of MyPy

MyPy provides a robust set of features designed to enhance the reliability and maintainability of Python code through static type analysis. Its core functionality revolves around verifying type hints and identifying potential type-related errors before code execution. The tool's capabilities extend to supporting modern Python typing standards and integrating into developer workflows.

  • Optional static type checking for Python code.
  • Verification of type hints as defined by PEP 484.
  • Detection of type-related bugs during development, prior to runtime.
  • Support for gradual typing, allowing a mix of static and dynamic typing within a single codebase.
  • Assistance in migrating existing Python codebases to incorporate static typing.
  • An available API for integration into other Python applications, documented at https://mypy.readthedocs.io/en/stable/extending_mypy.html.
  • Does not train on user data, ensuring privacy and compliance.
  • Enhances IDE features such as autocompletion, real-time linting, and usage finding.

use cases

Who Should Use MyPy?

MyPy is primarily designed for Python developers seeking to improve code quality, reliability, and maintainability in their projects. Its features are particularly beneficial for teams working on large or complex applications where type consistency is critical. The tool supports various development scenarios, from new projects to the migration of legacy code.

  • Python developers who want to catch type-related errors early in the development cycle.
  • Developers working on large Python projects to improve code reliability, maintainability, and readability.
  • Teams looking to add and verify type hints (PEP 484) in their Python programs for better documentation and error prevention.
  • Developers requiring gradual typing capabilities, allowing them to mix static and dynamic typing within their applications.
  • Teams assisting in the migration of existing Python codebases to static typing for increased confidence during refactoring.

pricing

MyPy Pricing & Plans

MyPy operates on a freemium model, primarily functioning as an open-source project. The core static type checker is freely available for download and use by individuals and organizations. This model ensures that all developers have access to its full functionality without any direct cost. There are no tiered subscription plans or usage-based fees for the MyPy tool itself. Any 'freemium' aspect would typically refer to potential third-party integrations, commercial support, or enterprise-level services built around MyPy, none of which are directly offered by the MyPy project itself.

  • Free: Full functionality of the MyPy static type checker, available as an open-source Python library.

Similar Tools

MyPy vs Competitors

MyPy is a prominent static type checker in the Python ecosystem, but it operates within a competitive landscape that includes several other tools offering similar or complementary functionalities. These alternatives often differentiate themselves through performance, strictness, type inference capabilities, or additional static analysis features.

1
PyrightOn StorkCompare

Pyright is known for its speed and aggressive type inference, often providing instant feedback in IDEs like VS Code via its Pylance extension.

Pyright is generally faster than MyPy, especially for large codebases, and offers more aggressive type inference, sometimes being more forgiving with untyped code. It is often integrated with VS Code through the Pylance extension, providing a smooth developer experience.

2
PytypeOn StorkCompare

Pytype uses type inference to determine types by analyzing code flow, rather than relying strictly on explicit type annotations.

Unlike MyPy, Pytype attempts to infer types even without explicit annotations, making it suitable for codebases with fewer type hints. It tends to be more lenient, allowing operations that work at runtime even if they might contradict annotations.

3
PyreOn StorkCompare

Pyre is a comprehensive tool that combines a type checker with a static code analysis tool (Pysa) for enhanced security analysis.

Pyre offers a similar approach to MyPy and Pytype in handling untyped code leniently, allowing gradual adoption of type annotations. Its integration with Pysa provides additional static analysis capabilities beyond just type checking, which MyPy does not inherently offer.

4
PyreflyOn StorkCompare

Built by Meta and written in Rust, Pyrefly aims to be a faster and more efficient next-generation type checker for Python.

Pyrefly is a newer, Rust-based alternative to MyPy, promising significantly faster performance, though it is still in active development and not yet fully mature. It serves the same core purpose of statically analyzing Python code for type correctness but with a focus on speed and efficiency.

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