JSON to C# Class Converter

When you need a JSON to C# converter

Almost every .NET project reads JSON at some point: responses from a third-party API, webhook payloads, configuration files or data exported from another system. Writing the matching C# classes by hand is slow and easy to get wrong, especially when the JSON is deeply nested. A converter builds the first version for you in seconds, so you can spend your time on the logic that uses the data.

How to use the generated code

1. Paste a representative JSON sample into the box. A sample that includes optional fields gives better results.
2. Choose class or record, the attribute style your project uses, and whether you want nullable reference types.
3. Copy the code into a new .cs file in your project.
4. Deserialize the JSON into the root class:

var options = new JsonSerializerOptions { PropertyNameCaseInsensitive = true };
    var data = JsonSerializer.Deserialize<Root>(json, options);

If the JSON root is an array, deserialize to List<Root> instead.

How the converter decides on types

• Numbers: whole numbers become int (or long when they are large), numbers with a fraction become double, or decimal if you choose it.
• Dates and GUIDs: strings that look like ISO 8601 dates become DateTime, and strings in GUID format become Guid.
• Lists: items are merged into a single class. Fields missing from some items become nullable.
• Names: keys such as first_name become FirstName, and an attribute keeps the link to the original JSON key.

Check the result before you rely on it

The generated code is a strong starting point, not a finished model. A single sample cannot show every possible value, so review the types it chose. Fields that hold money are usually better as decimal. A field that is always null in your sample will be typed as object because the real type is unknown. Rename properties to match your conventions, and add validation where your application needs it.