python-attrs/cattrs

Health v2 · maintenance only

Adoption not part of the score

1050 stars · 152 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

cattrs is a Python library for converting unstructured data like dictionaries into attrs classes and dataclasses and back, with validation. It supports recursive structuring/unstructuring of complex and nested types with customizable hooks.

Use cases

• convert json dicts into python attrs classes
• serialize dataclasses to dictionaries
• deserialize nested api payloads into typed objects
• validate unstructured data at system edges
• register custom converters for specific types

When to choose

• you use attrs classes or dataclasses and need flexible (un)structuring
• you need recursive conversion of complex nested types
• you want validation separated from your data model

When to avoid

• you need a full schema-based validation framework like pydantic
• your data model doesn't use attrs or dataclasses
• you only need simple json encoding of plain dicts

Facets

library · maturity active

serialization form-handling parser developer-tools apis python cross-platform attrs dataclasses structuring deserialization type-driven data-engineering

Member repositories

For agents

markdown · JSON · MCP: product_card(name="python-attrs/cattrs")