marshmallow-sqlalchemy

What it is and what it does

marshmallow-sqlalchemy bridges SQLAlchemy ORM models and the marshmallow serialization library, letting you define schemas that automatically map database columns and relationships to serializable fields. Instead of writing field definitions by hand, you declare a schema class pointing to your SQLAlchemy model, and the library generates the fields for you—optionally including relationships and foreign keys. You can then use the schema to dump model instances to dictionaries (for JSON APIs) or load dictionaries back into model instances.

The package handles the common pattern of building REST APIs or other services that need to convert between database objects and wire formats. It integrates with SQLAlchemy sessions to manage object loading and validation, and supports both explicit field declaration (auto_field) and full automatic schema generation (SQLAlchemyAutoSchema). The library is lightweight, with no dependencies beyond marshmallow and SQLAlchemy themselves.

Use it for

• Build REST APIs that serialize SQLAlchemy models to JSON responses and validate incoming request data
• Generate API documentation schemas automatically from your database model definitions
• Validate and deserialize incoming data directly into ORM instances within a session
• Export database records to JSON or other formats for reporting or data migration
• Decouple your API contract from your internal model structure using schema field customization

Worth the install?

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Install

marshmallow-sqlalchemy on PyPI

Before you install

Low friction: pure Python wheel with only two runtime dependencies (marshmallow and SQLAlchemy). Actively maintained with recent commits and releases spanning since 2015.

Requires Python >= 3.10, marshmallow >= 3.18.0, and SQLAlchemy >= 1.4.40. Models must be declared before schemas are instantiated.

License in practice

MIT licensed under permissive terms, allowing use in commercial and proprietary projects with minimal restrictions.

Quickstart

pip install marshmallow-sqlalchemy

from marshmallow_sqlalchemy import SQLAlchemyAutoSchema

class AuthorSchema(SQLAlchemyAutoSchema):
    class Meta:
        model = Author
        load_instance = True

schema = AuthorSchema()
author_dict = schema.dump(author_instance)
author_obj = schema.load(author_dict, session=db_session)

Package facts

Evidence: marshmallow_sqlalchemy-1.5.0-py3-none-any.whl

Tags

More Database packages

See also marshmallow-mongoengine · sqlalchemy-serializer · marshmallow · marshmallow-jsonapi · flask-marshmallow · sqlalchemy-repr · amundsen-common · graphene-sqlalchemy · marshmallow-jsonschema · marshmallow-union