---
id: annotated-types
version: "0.8.0"
license: MIT
license_treatment: permissive
maintenance: active
---

# annotated-types — Reusable constraint types to use with typing.Annotated

License: permissive · Maintenance: active · Popularity: top 100 on PyPI

## Install

pip install annotated-types
uv add annotated-types
poetry add annotated-types

## Description

# annotated-types

[![CI](https://github.com/annotated-types/annotated-types/workflows/CI/badge.svg?event=push)](https://github.com/annotated-types/annotated-types/actions?query=event%3Apush+branch%3Amain+workflow%3ACI)
[![pypi](https://img.shields.io/pypi/v/annotated-types.svg)](https://pypi.python.org/pypi/annotated-types)
[![versions](https://img.shields.io/pypi/pyversions/annotated-types.svg)](https://github.com/annotated-types/annotated-types)
[![license](https://img.shields.io/github/license/annotated-types/annotated-types.svg)](https://github.com/annotated-types/annotated-types/blob/main/LICENSE)

[PEP-593](https://peps.python.org/pep-0593/) added `typing.Annotated` as a way of
adding context-specific metadata to existing types, and specifies that
`Annotated[T, x]` _should_ be treated as `T` by any tool or library without special
logic for `x`.

This package provides metadata objects which can be used to represent common
constraints such as upper and lower bounds on scalar values and collection sizes,
a `Predicate` marker for runtime checks, and
descriptions of how we intend these metadata to be interpreted. In some cases,
we also note alternative representations which...

## AI interpretation — verify before relying

Provides reusable metadata objects for use with `typing.Annotated` to express common constraints like bounds, lengths, and predicates on values without requiring runtime checks.

Verdict: A lightweight, zero-dependency library for expressing type constraints via PEP 593 annotations. Active maintenance, MIT license, and top-100 popularity make it a safe choice for projects needing declarative constraint metadata without runtime overhead.

[View on SkillFed](https://skillfed.io/packages/annotated-types) · [View on PyPI](https://pypi.org/project/annotated-types/)