JSON to Pydantic
Generate Pydantic models from JSON data. Inspired by JSON to TS extension and JSON to Pydantic website.
Features
- Converts JSON data to Pydantic model classes
- Handles nested objects and arrays
- Supports Python type annotations
- Supports aliasing for camelCase fields
- Option to reuse class definitions
- Option to make fields optional
- Supports avoiding reserving Python keywords as field names
- Duplicate class name and field name prevention
- Union types and array types merging
- Indents the generated code according to the editor settings
Usage
Extension Settings
This extension provides settings to modify the generated code. They are:
Extension Settings Examples
The following JSON will be the input for all the examples that follow.
{
"id": 101,
"title": "First Post",
"content": "This is the content of the post.",
"isActive": true,
"createdAt": "2025-07-01T14:20:00Z",
"updatedAt": "2025-07-01T15:00:00Z",
"userProfile": {
"userId": 501,
"firstName": "Alice",
"lastName": "Johnson",
"emailAddress": "alice@example.com"
},
"createdBy": {
"userId": 501,
"firstName": "Alice",
"lastName": "Johnson",
"emailAddress": "alice@example.com"
},
"updatedBy": {
"userId": 502,
"firstName": "Bob",
"lastName": "Smith",
"emailAddress": "bob@example.com"
},
"tags": ["json", "example", "camelCase"],
"metadata": {
"viewsCount": 250,
"likesCount": 18,
"isFeatured": false
}
}
With all default settings, the resulting code will be as follows:
from __future__ import annotations
from typing import List
from pydantic import BaseModel
class UserProfile(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class CreatedBy(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class UpdatedBy(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class Metadata(BaseModel):
viewsCount: int
likesCount: int
isFeatured: bool
class Model(BaseModel):
id: int
title: str
content: str
isActive: bool
createdAt: str
updatedAt: str
userProfile: UserProfile
createdBy: CreatedBy
updatedBy: UpdatedBy
tags: List[str]
metadata: Metadata
json-to-pydantic.defaultRootClassName
It can be defined with any name, including names that are not allowed for other classes generated from the input (such as True, False or names starting with numbers), and it is the user's responsibility to avoid this. For example purposes, the defined name will be "Root". If defined this way, the resulting code will be as follows:
from __future__ import annotations
from typing import List
from pydantic import BaseModel
class UserProfile(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class CreatedBy(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class UpdatedBy(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class Metadata(BaseModel):
viewsCount: int
likesCount: int
isFeatured: bool
class Root(BaseModel):
id: int
title: str
content: str
isActive: bool
createdAt: str
updatedAt: str
userProfile: UserProfile
createdBy: CreatedBy
updatedBy: UpdatedBy
tags: List[str]
metadata: Metadata
json-to-pydantic.preferClassReuse
If set to true, the resulting code will be as follows:
from __future__ import annotations
from typing import List
from pydantic import BaseModel
class UserProfile(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class Metadata(BaseModel):
viewsCount: int
likesCount: int
isFeatured: bool
class Model(BaseModel):
id: int
title: str
content: str
isActive: bool
createdAt: str
updatedAt: str
userProfile: UserProfile
createdBy: UserProfile
updatedBy: UserProfile
tags: List[str]
metadata: Metadata
json-to-pydantic.forceOptional
There are three options to this setting: "None", "OnlyRootClass" and "AllClasses". "None" is the default option, so if set to this option, the resulting code will be like the default example code shown above. Following is the resulting code for the other options:
"OnlyRootClass": Optional[...] will only be set to the root class.
from __future__ import annotations
from typing import List, Optional
from pydantic import BaseModel
class UserProfile(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class CreatedBy(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class UpdatedBy(BaseModel):
userId: int
firstName: str
lastName: str
emailAddress: str
class Metadata(BaseModel):
viewsCount: int
likesCount: int
isFeatured: bool
class Model(BaseModel):
id: Optional[int] = None
title: Optional[str] = None
content: Optional[str] = None
isActive: Optional[bool] = None
createdAt: Optional[str] = None
updatedAt: Optional[str] = None
userProfile: Optional[UserProfile] = None
createdBy: Optional[CreatedBy] = None
updatedBy: Optional[UpdatedBy] = None
tags: Optional[List[str]] = None
metadata: Optional[Metadata] = None
"AllClasses": Optional[...] will be set to all generated classes.
from __future__ import annotations
from typing import List, Optional
from pydantic import BaseModel
class UserProfile(BaseModel):
userId: Optional[int] = None
firstName: Optional[str] = None
lastName: Optional[str] = None
emailAddress: Optional[str] = None
class CreatedBy(BaseModel):
userId: Optional[int] = None
firstName: Optional[str] = None
lastName: Optional[str] = None
emailAddress: Optional[str] = None
class UpdatedBy(BaseModel):
userId: Optional[int] = None
firstName: Optional[str] = None
lastName: Optional[str] = None
emailAddress: Optional[str] = None
class Metadata(BaseModel):
viewsCount: Optional[int] = None
likesCount: Optional[int] = None
isFeatured: Optional[bool] = None
class Model(BaseModel):
id: Optional[int] = None
title: Optional[str] = None
content: Optional[str] = None
isActive: Optional[bool] = None
createdAt: Optional[str] = None
updatedAt: Optional[str] = None
userProfile: Optional[UserProfile] = None
createdBy: Optional[CreatedBy] = None
updatedBy: Optional[UpdatedBy] = None
tags: Optional[List[str]] = None
metadata: Optional[Metadata] = None
json-to-pydantic.aliasCamelCase
If set by true, camelCase fields will be aliased to snake_case fields.
from __future__ import annotations
from typing import List
from pydantic import BaseModel, Field
class UserProfile(BaseModel):
user_id: int = Field(..., alias='userId')
first_name: str = Field(..., alias='firstName')
last_name: str = Field(..., alias='lastName')
email_address: str = Field(..., alias='emailAddress')
class CreatedBy(BaseModel):
user_id: int = Field(..., alias='userId')
first_name: str = Field(..., alias='firstName')
last_name: str = Field(..., alias='lastName')
email_address: str = Field(..., alias='emailAddress')
class UpdatedBy(BaseModel):
user_id: int = Field(..., alias='userId')
first_name: str = Field(..., alias='firstName')
last_name: str = Field(..., alias='lastName')
email_address: str = Field(..., alias='emailAddress')
class Metadata(BaseModel):
views_count: int = Field(..., alias='viewsCount')
likes_count: int = Field(..., alias='likesCount')
is_featured: bool = Field(..., alias='isFeatured')
class Model(BaseModel):
id: int
title: str
content: str
is_active: bool = Field(..., alias='isActive')
created_at: str = Field(..., alias='createdAt')
updated_at: str = Field(..., alias='updatedAt')
user_profile: UserProfile = Field(..., alias='userProfile')
created_by: CreatedBy = Field(..., alias='createdBy')
updated_by: UpdatedBy = Field(..., alias='updatedBy')
tags: List[str]
metadata: Metadata
