MonkeyType
Automatically generates Python type annotations from runtime data.
Pricing
Free tier
Flat rate
Adoption
↘CoolingLicense
Open Source
Data freshness
Aging · Jun 8, 2026Overview
What is MonkeyType?
MonkeyType is a system that automatically generates static type annotations for Python code by collecting and analyzing runtime types. This tool helps developers improve the reliability of their code without manually writing type hints, making it easier to maintain large projects.
Key differentiator
“MonkeyType stands out by automating the generation of Python type annotations from runtime data, offering a unique solution to enhance code reliability without manual effort.”
Capability profile
Capability Radar
Honest assessment
Strengths & Weaknesses
↑ Strengths
↓ Weaknesses
MonkeyType may struggle with inferring types in complex scenarios involving generics, unions, or advanced Python features.
Collecting runtime type information can introduce performance penalties, especially in CPU-bound applications where every millisecond counts.
MonkeyType relies on runtime data to infer types, which means it may fail to provide accurate annotations for dynamically generated or modified code.
The documentation lacks detailed explanations and practical use cases, making it difficult for new users to fully leverage the tool's capabilities.
Fit analysis
Who is it for?
✓ Best for
Python developers working on large-scale applications who want to add static typing without manual effort.
Teams looking to improve the reliability and maintainability of their Python codebase by leveraging runtime data for type annotations.
✕ Not a fit for
Projects that require real-time or interactive type checking, as MonkeyType operates post-execution.
Developers who prefer manually writing type hints for fine-grained control over type definitions.
Cost structure
Pricing
Free Tier
Available
Open source — free to use
Starts at
$0
Model
Flat rate
Enterprise
None
Performance benchmarks
How Fast Is It?
Ecosystem
Relationships
Next step
Get Started with MonkeyType
Step-by-step setup guide with code examples and common gotchas.