ty

An extremely fast Python type checker and language server.

GrowingOpen SourceLow lock-in

Pricing

Free tier

Flat rate

Adoption

Rising

License

Open Source

Data freshness

Verified · Jul 16, 2026

Overview

What is ty?

Ty is an open-source tool that provides rapid type checking for Python code. It serves as a powerful language server, enhancing developer productivity by offering real-time feedback on type errors.

Key differentiator

Ty stands out as an extremely fast and efficient tool for Python type checking, offering real-time feedback through its language server capabilities.

Capability profile

Capability Radar

Ease of StartEcosystemValueMaturityFlexibilityScale Ready

Honest assessment

Strengths & Weaknesses

↑ Strengths

Extremely fast type checking for Python codemedium

Serves as a language server providing real-time feedbackmedium

Enhances developer productivity with accurate error detectionmedium

↓ Weaknesses

Steep learning curve for non-Python developershigh

API requires Python-specific patterns, TypeScript SDK is community-maintained

Frequent breaking changes between versionsmedium

v0.1 to v0.2 migration required rewriting chain definitions

Limited integrations with non-Python tools and ecosystemshigh

Primarily designed for Python, limited support for other languages or IDEs

Performance issues in large codebasesmedium

Type checking can become slow and resource-intensive as project size grows

Fit analysis

Who is it for?

✓ Best for

Developers working on large-scale Python projects who need fast type checking and real-time error detection

Teams that require efficient static analysis tools for maintaining high-quality Python codebases

Individual developers looking to enhance their productivity with a powerful language server

✕ Not a fit for

Projects requiring cross-language support beyond Python

Developers who prefer manual type checking over automated solutions

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 ty

Step-by-step setup guide with code examples and common gotchas.

View Setup Guide →