JSON to C# Class Converter

How the JSON to C# Class Converter Works

You've got a JSON response — from an API you're integrating, a webhook payload, a config file, or a database export — and you need a matching C# class to deserialize it into. For a handful of fields that's a two-minute job. For a real API response with nested objects, arrays, and a dozen properties, transcribing it by hand is slow and exactly the kind of task where you mistype a property name or pick the wrong numeric type without noticing. This tool reads one real JSON sample and generates the matching class or record tree in your browser, with no account and no server round-trip for the conversion. It's deliberately a sample-based inference tool, not a JSON Schema or OpenAPI generator — it looks at the actual values in front of it and makes a best-effort type guess for each one, the same way you would if you were doing it by hand, just faster and without typos. That also means it has the same blind spot you'd have: if a field is null in your sample, or an array's later items look different from its first, the tool can't see what it wasn't shown. Treat the output as a strong first draft — usually correct, always worth a quick read before it goes into a real codebase.

How to use it

1. Paste a real JSON object or array into the input panel, or start from the bundled sample to see the tool in action.
2. Set a root class name if you want something more specific than the default (Root for an object, RootItem for an array) — useful once you have several generated files in the same project.
3. Pick Class or Record for the output style, and turn on Nullable types if you want reference-typed properties marked ? defensively, even where this particular sample wasn't null.
4. Turn on JSON attributes if any of your keys have hyphens, dots, spaces, or a leading digit — the generator adds [JsonPropertyName] only where the PascalCase conversion would otherwise break round-tripping.
5. Set a namespace if you want the output wrapped in one, then copy or download the result and review it — especially the "what this doesn't do" items below — before compiling it into your project.

Worked examples

{
  "id": 1,
  "email": "jane@example.com",
  "createdAt": "2024-03-11T09:15:00Z",
  "isVerified": true,
  "profile": {
    "displayName": "Jane Smith",
    "bio": null
  },
  "roles": ["admin", "editor"]
}

public class Root
{
    public int Id { get; set; }
    public string Email { get; set; }
    public DateTime CreatedAt { get; set; }
    public bool IsVerified { get; set; }
    public Profile Profile { get; set; }
    public List<string> Roles { get; set; }
}

public class Profile
{
    public string DisplayName { get; set; }
    public string? Bio { get; set; }
}

[
  { "sku": "AB-100", "price": 49.99, "inStock": true },
  { "sku": "AB-101", "price": 12.5, "inStock": false }
]

namespace MyApp.Models;

public class RootItem
{
    public string? Sku { get; set; }
    public double Price { get; set; }
    public bool InStock { get; set; }
}

{
  "user-id": 42,
  "first.name": "Alex",
  "2fa_enabled": true,
  "snake_case_key": "value"
}

using System.Text.Json.Serialization;

public class Root
{
    [JsonPropertyName("user-id")]
    public int UserId { get; set; }
    [JsonPropertyName("first.name")]
    public string FirstName { get; set; }
    [JsonPropertyName("2fa_enabled")]
    public bool 2faEnabled { get; set; }
    public string SnakeCaseKey { get; set; }
}

Common errors and what they mean