Pydantic

Pydantic v2 brings Rust-powered validation that's 5-50x faster than v1, making it the standard for FastAPI request/response validation and settings management. The BaseModel approach with type hints feels natural in modern Python, and field validators handle everything from email formats to custom business logic without boilerplate. The v2 migration changes method names (dict() becomes model_dump(), parse_obj() becomes model_validate()) but the performance jump and better error messages make it worth updating. If you're building APIs, parsing config files, or just want runtime type safety without writing manual checks, this is the de facto choice. The progressive disclosure here covers field constraints, custom types, and the validator decorators you'll actually use day-to-day.

skills.sh installs: 2.2K
GitHub stars: 44
last updated: May 16, 2026

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Install

$ npx -y skills add bobmatnyc/claude-mpm-skills --skill pydantic --agent claude-code

Installs into .claude/skills of the current project.

Files

Pydantic Validation Skill

Summary

Python data validation using type hints and runtime type checking with Pydantic v2's Rust-powered core for high-performance validation.

When to Use

API request/response validation (FastAPI, Django)
Settings and configuration management (env variables, config files)
ORM model validation (SQLAlchemy integration)
Data parsing and serialization (JSON, dict, custom formats)
Type-safe data classes with automatic validation
CLI argument parsing with type safety

Quick Start

from pydantic import BaseModel, Field, EmailStr
from datetime import datetime

class User(BaseModel):
    id: int
    name: str = Field(..., min_length=1, max_length=100)
    email: EmailStr
    created_at: datetime = Field(default_factory=datetime.now)
    is_active: bool = True

# Validate data
user = User(id=1, name="Alice", email="alice@example.com")
print(user.model_dump())  # {'id': 1, 'name': 'Alice', ...}

# Automatic type coercion
user2 = User(id="2", name="Bob", email="bob@example.com")
assert user2.id == 2  # String "2" coerced to int

SKILL.md on GitHub