Pydantic Migration Guides
Replace simple @validator usage with @field_validator in the safe Pydantic v2 subset.
Start here
Use @field_validator for simple field validators, but stop when the validator depends on values, field, config, each_item, or always.
Stop before automation when: values, field, or config parameters. each_item=True or always=True behavior.
from pydantic import BaseModel, field_validator
class User(BaseModel):
@field_validator("email")
@classmethod
def clean_email(cls, value):
return value.lower()
Repo fit check
Run the matching scanner locally first. Read the free findings and manual alternatives; consider paid cleanup only if supported patterns repeat enough to justify the price.
Example scan summary
supported_findings: 38
manual_review_findings: 6
files_uploaded: 0
confidence: reviewableWhy this page exists
Simple validators are safe cleanup; signature-heavy validators need review.
Direct answer
Use @field_validator for simple field validators, but stop when the validator depends on values, field, config, each_item, or always.
Example
from pydantic import BaseModel, validator
class User(BaseModel):
@validator("email")
def clean_email(cls, value):
return value.lower()
from pydantic import BaseModel, field_validator
class User(BaseModel):
@field_validator("email")
@classmethod
def clean_email(cls, value):
return value.lower()
Decision path
The cleanup pack is strongest when the repo still uses direct pydantic imports and a clean validator/settings/config subset.
Before checkout
Price: $249.99 per team.
Use the exact-problem guides as a triage layer, then decide whether the repo is inside the supported subset.
FAQ
Use @field_validator for simple field validators, but stop when the validator depends on values, field, config, each_item, or always.
Automate only the supported subset: Simple @validator to @field_validator rewrites. Import cleanup for field_validator. Manual-review findings for signature-heavy cases. Keep these cases in manual review: values, field, or config parameters. each_item=True or always=True behavior. Validators that change model-level semantics.
Use Pydantic v1 to v2 Migration Cleanup Pack only when this pattern repeats across enough files that manual cleanup is still costly. Use the free report and upstream guide to evaluate fit. Buy only if repeated supported edits justify the price; no paid assessment is required.
Purchase fit
One matching page is not enough by itself. Run the local scan, then buy only when the same supported pattern appears often enough to matter.
Replace @validator with @field_validator, Move BaseSettings to pydantic-settings, Convert Config to model_config, Replace validate_arguments with validate_call, Replace @root_validator(pre=True) with @model_validator(mode="before"), Why post root validators need manual review, Move pydantic.v1 imports onto pydantic, Why Config.fields is a manual-review case