marshmallow
Object serialization and validation library for converting complex datatypes to and from native Python types and JSON.
data-validation-frameworks
76
Hero Score
Popularity
76
Performance
30
Ecosystem
100
Maturity
100
Dev Experience
75
⭐ 7,243 stars⬇ 20.3M downloads/wkFirst release: Nov 2013Last release: Aug 2026
Async Support: NoPlugin Extensions: Very highSpeed: MediumDoc Quality: Very highLearning Curve: Medium
Pros
- • Mature ecosystem with rich plugin support (Flask, SQLAlchemy, OpenAPI)
- • Works without type hints — flexible for dynamic schemas
- • Powerful pre/post-load hooks and custom field types
Cons
- • Slower than Pydantic and msgspec for validation-heavy workloads
- • More verbose schema definitions compared to type-hint-based libraries
- • No native async support