2 posts tagged with "validation"

The modern Python landscape offers two excellent tools for defining structured data: Dataclasses (introduced in Python 3.7) and Pydantic (a third-party library). While both help define classes for data, their core purpose, performance characteristics, and feature sets are fundamentally different.

Choosing between them depends on whether your primary need is simple data structuring (Dataclasses) or input validation and parsing (Pydantic).

It might seem excessive to define an entire Pydantic BaseModel for a single attribute when a simple type hint like user_id: str would suffice. However, using a single-attribute Pydantic model (often called a Wrapper Model or a Value Object) offers significant advantages, primarily around reusability, centralized validation, and complex parsing.

This pattern transforms a simple type hint into a powerful, reusable validation layer.