# agronholm/typeguard

Run-time type checker for Python

Repository: https://github.com/agronholm/typeguard
Canonical: https://ross.abutalabs.com/products/typeguard
Language: Python
License: NOASSERTION
License Family: other
Last push: 2026-07-26T08:39:40+00:00

## Health v2 (maintenance only)
Score: 91/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 94, release rhythm 83, longevity 100
- inputs: {"age_days": 3902, "days_push": 38, "days_rel": 38, "gap_med": 77.5, "n_releases_24m": 9}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1780, forks 140 (observed 2026-08-28T04:05:35.362787+00:00)

## What it is
Typeguard is a Python library that performs run-time type checking based on PEP 484 type annotations, complementing static type checkers. It offers a check_type function, per-call checking helpers, and code instrumentation via a @typechecked decorator or an import hook.

## Use cases
- validate function arguments against type hints at runtime
- check arbitrary objects against complex type annotations
- catch type violations that static checkers miss
- automatically instrument modules with type checking on import
- verify generator yield and send values match annotations

## When to choose
- you want runtime enforcement of type hints in Python code
- you need isinstance-like checks supporting generic and arbitrary annotations
- you want automatic type checking without modifying function bodies

## When to avoid
- you only need static type analysis (use mypy or pyright)
- runtime type checking overhead is unacceptable in hot code paths
- target module source code is unavailable for instrumentation

## Facets
- artifact type: library
- maturity: active
- function: type-system, testing, developer-tools
- domain: developer-tools, programming-languages, testing
- platform: python, cross-platform
- tags: runtime-type-checking, type-annotations, pep-484, type-hints, instrumentation

## Member repositories
- agronholm/typeguard (main) score 91

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:35.362787+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:24:33.336265+00:00, confidence not recorded.
  - readme: https://github.com/agronholm/typeguard (fetched 2026-08-28T04:05:35.362787+00:00, sha 89b222c6070f)
  - registry_pypi: https://pypi.org/pypi/typeguard/json (fetched 2026-08-29T11:03:06.287510+00:00, sha b469e457353c)
- Data as of 2026-08-30T08:39:29.467469+00:00.