JSON to C# Class Generator

How to Use the Free Client-Side JSON to C# Generator

This generator produces C# POCO classes with automatic properties from a JSON sample, all inside your browser. It can add JsonProperty attributes for serialization compatibility and nullable reference type annotations for modern C#.

Nested objects become nested classes within the main class, keeping the model organized.

1. Copy your JSON data and paste it into the input textarea above.
2. Toggle nullable detection, JsonProperty attributes, and naming style preferences.
3. Click Generate, then copy the C# classes or download the .cs file.

When to Use JSON to C#

.NET client applications that consume JSON need models that deserialize cleanly, and this generator produces them from an actual response sample. When you build a client against an API, you paste the response, generate the POCOs, and wire them into System.Text.Json or Newtonsoft.Json deserialization with confidence. The tool also covers DTO generation from JSON schemas during REST service development and rapid prototyping of class hierarchies from sample data.

The options address the real friction points in .NET. JsonProperty attributes map snake_case JSON keys to PascalCase C# properties, which is essential when the API naming does not match your code conventions. Nullable reference types mark fields that may be null, distinguishing required data from optional data for better null safety. Whether you standardize on System.Text.Json or Newtonsoft.Json, the generated code fits your chosen stack.

JSON to C# Tips and Best Practices

1. Enable JsonProperty attributes when your API returns snake_case keys, so PascalCase properties map back correctly during deserialization.
2. Turn on nullable reference types to correctly type fields that may be absent or null in responses.
3. Review generated numeric and collection types, adjusting them to match the actual data range in your contract.
4. Confirm your target framework supports the nullable annotations before copying the code into your project.

Why Client-Side Privacy Matters for .NET Model Generation from API Contracts

API contracts in a .NET shop often wrap customer data, payment details, and internal identifiers, and the models you generate mirror those structures. Uploading the sample to a generator gives an external service visibility into your data layer.

This JSON to C# generator converts everything locally in your browser, so the sample never leaves your device. You can build models for regulated or internal systems without exposing contract details.