Tag: serialization

2 articles

Fix: Marshmallow Not Working — Schema Errors, Load vs Dump, and Field Validation

May 17, 2026

How to fix Marshmallow errors — Schema not validated on dump, ValidationError messages format, unknown field handling, missing vs default, post_load object construction, and Marshmallow 3 to 4 migration.

python marshmallow serialization validation flask debugging

Fix: msgspec Not Working — Struct Definition, Type Validation, and JSON/MessagePack Encoding

May 11, 2026

How to fix msgspec errors — Struct field type not supported, ValidationError on decode, msgspec vs Pydantic differences, custom type hooks, frozen Struct mutation, and JSON Schema generation.

python msgspec serialization json msgpack fastapi debugging