JSON to C# Class Converter

Generate C# classes or records from a JSON example — PascalCase properties with [JsonPropertyName] attributes for System.Text.Json, nullable types for partially-present fields.

From payload to .NET model

Paste a JSON example and get C# models ready for System.Text.Json: PascalCase properties with [JsonPropertyName] attributes wherever the JSON key differs (snake_case, dashes), nested objects as named classes, arrays as List<T>, and nullable types (long?, string?) for fields the sample proves optional. Choose classic classes or C# 9+ records for immutable DTOs.

Worked example

using System.Text.Json.Serialization;

public class Root
{
    public long Id { get; set; }

    [JsonPropertyName("order_status")]
    public string OrderStatus { get; set; }

    public Customer Customer { get; set; }

    public List<Line> Lines { get; set; }
}

When to use it

• Typing responses from third-party APIs in ASP.NET services.
• Building DTO layers from real payloads instead of docs.
• Keeping C# models in sync with the JSON contract during integration work.

Limitations to know

• Targets System.Text.Json; for Newtonsoft.Json swap the attribute to [JsonProperty] — the shape is identical.
• Optionality comes from evidence in arrays; single-object samples emit non-nullable properties — adjust against the real contract.
• Whole numbers become long and decimals double, for the same safety reasons as the Java converter.

Common errors and fixes

• Two classes named User and User2 — two different shapes shared a key name; align the shapes or rename after pasting.
• Missing rare fields — the sample did not contain them; paste a more complete example and regenerate.

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