Does this generate Pydantic v1 or v2 code?

This tool generates modern Pydantic v2 syntax by default, utilizing ConfigDict(populate_by_name=True) instead of the deprecated class Config from Pydantic v1. It runs without deprecation warnings on Pydantic 2.0 through 2.13+.

How do Field aliases work in Pydantic?

If a JSON key contains hyphens or camelCase (e.g. 'first-name' or 'userEmail'), the generator creates a Python-safe snake_case attribute (first_name) with Field(alias='first-name'). Because populate_by_name is enabled, you can initialize the model with either name.

JSON to Pydantic Converter

Convert JSON payloads into robust Pydantic v2 data models with BaseModel, ConfigDict, Field aliases, nested object support, and FastAPI compatibility.

Target:

Load Template:

JSON Input21 lines · 507 chars

Pydantic v2.py

Generated Pydantic v2 code will appear here

Paste or type valid JSON on the left to see instant, production-ready models.

Ready to compile · Deterministic output.py

100% Client-Side Privacy: Your JSON is parsed and compiled entirely in your browser using local Web APIs. Nothing is sent to any server.

Zero Network Transfer

What is the JSON to Pydantic Converter?

The PriyGop JSON to Pydantic Converter generates production-ready Pydantic v2 data models from sample JSON payloads. Pydantic is the standard data validation framework for FastAPI, LangChain, and modern Python backends, converting untyped JSON dictionaries into validated, type-safe Python objects.

Pydantic v2 Standards & Best Practices

BaseModel Inheritance: Every generated class subclasses BaseModel.
ConfigDict: Configured with model_config = ConfigDict(populate_by_name=True) for smooth deserialization.
Field Aliases: When JSON keys use hyphens or camelCase, fields use idiomatic snake_case with Field(alias="original_key").
Optional Fields: Missing or nullable properties default to None with type | None annotations.

Our Tool Features

Why developers and engineers prefer this tool for everyday development workflows.

Cross-Device Compatibility

Works seamlessly on all modern desktop, tablet, and mobile browsers including Chrome, Firefox, Safari, Edge on Windows, macOS, Linux, Android, and iOS.

Fast In-Browser Execution

Processes your data in real-time directly inside your browser. No queue wait times, no network round-trips, and zero latency.

100% Client-Side Privacy

Your code, tokens, passwords, and files are never transmitted to any external server or saved in logs. Everything runs locally in memory.

Instant File & Clipboard Input

Supports one-click sample loading, file drag-and-drop, and pasting directly from your clipboard (Ctrl + V) for effortless workflows.

Strict Standards Compliant

Built strictly according to official specifications (RFCs, W3C, ISO, and standard cryptographic algorithms) ensuring accurate output every time.

Unlimited Free Usage

No registration, no accounts, no subscriptions, and no hidden daily quotas. Use this tool as many times as you need without restrictions.

Recent Updates & Improvements

Continuously maintained and improved based on developer feedback.

Client-Side Speed & Performance UpgradeRecent Update

Optimized processing algorithms with Web Workers and native browser APIs (SubtleCrypto, Canvas 2D) for instantaneous zero-latency execution.

Clipboard Paste & Drag-and-Drop AddedFeature Added

Added instant clipboard pasting (Ctrl + V) and drag-and-drop file support to accelerate developer productivity without manual downloads.

Enhanced Mobile & Touch Device ExperienceUI/UX Update

Redesigned responsive touch controls, flexible copy buttons, and camera preview framing for mobile and tablet browsers.

How To Use JSON to Pydantic Converter Online?

Follow these quick steps to get instant, accurate results in seconds.

Input JSON Data

Paste your API payload or database document.

Paste any valid JSON string into the editor.
Click 'Sample' to inspect a realistic order model with line items.

JSON PayloadClient-Side

{
  "order_id": "ORD-123",
  "total_price": 49.99,
  "customer_email": "jane@example.com"
}

Instant ExecutionReady

Configure Pydantic v2 Settings

Adjust field aliasing and naming conventions.

Keep 'ConfigDict(populate_by_name=True)' enabled to support both snake_case and original keys.
Enable Multi-Sample Mode if you have multiple JSON responses to infer optional fields.

Pydantic v2 OutputClient-Side

class Order(BaseModel):
    model_config = ConfigDict(populate_by_name=True)
    order_id: str
    total_price: float

Instant ExecutionReady

Integrate into FastAPI

Download or copy the generated .py file.

Copy directly into your schemas.py or models.py file.
Use as request or response models in FastAPI routes.

FastAPI IntegrationClient-Side

@app.post("/orders")
def create_order(payload: Order): ...

Instant ExecutionReady

Supported Formats & Syntax Examples

Common input data types and real-world representations supported by this tool.

Pydantic v2 BaseModel with ConfigDict

Pydantic v2

Nested models with populate_by_name configuration.

Example Syntax

from pydantic import BaseModel, Field, ConfigDict

class Profile(BaseModel):
    model_config = ConfigDict(populate_by_name=True)
    bio: str
    years_experience: int

class User(BaseModel):
    model_config = ConfigDict(populate_by_name=True)
    user_id: int
    profile: Profile
    metadata: dict | None = None

Fully compatible with Pydantic 2.x without deprecated v1 Config classes.

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from pydantic import BaseModel, Field, ConfigDict class Profile(BaseModel): model_config = ConfigDict(populate_by_name=True) bio: str years_experience: int class User(BaseModel): model_config = ConfigDict(populate_by_name=True) user_id: int profile: Profile metadata: dict | None = None