FastAPI architecture recommended
Pydantic Best Practices
Pydantic v2 validation patterns, field validators, custom base models, settings management, and serialization for FastAPI applications.
- Difficulty
- intermediate
- Read time
- 1 min read
- Version
- v1.0.0
- Confidence
- established
- Last updated
Quick Reference
Use Pydantic v2 with ConfigDict for configuration. Use Field() for constraints (min_length, ge, pattern). Use @field_validator for custom validation. Use pydantic-settings for env vars with SettingsConfigDict. Use model_dump(exclude_unset=True) for partial updates. Always validate at API boundaries.
Use When
- Defining request/response schemas
- Validating user input
- Managing configuration and settings
- Serializing data for APIs
Skip When
- Using non-Pydantic validation libraries
- Simple scripts without validation needs
Pydantic Best Practices
Pydantic v2 validation patterns, field validators, custom base models, settings management, and serialization for FastAPI applications.