JSON to C# Class Generator

Turn JSON into C# model classes

This JSON to C# converter reads a JSON sample and generates strongly typed C# classes that match its shape. Every object becomes a public partial class, every property gets a PascalCase name with a serializer attribute that maps it back to the original JSON key, and nested objects become their own classes named after the property that holds them. Arrays turn into List<T> or T[], ISO dates become DateTimeOffset, and values that are sometimes missing or null are emitted as nullable types so your code compiles against real-world payloads instead of an idealised one.

Under the hood the tool uses quicktype, a mature type-inference engine that merges every element of an array before deciding on a type. That means a list of orders where only some orders carry a coupon still produces one Order class with an optional Coupon property, rather than a class that only fits the first element.

System.Text.Json or Newtonsoft

Modern .NET projects usually rely on System.Text.Json, which is the default here: properties are decorated with [JsonPropertyName] and the output includes a FromJson factory, a ToJson extension method and converter settings for ISO dates. If your codebase still uses Json.NET, switch the serializer to Newtonsoft and you get [JsonProperty] attributes with the same helpers built on JsonConvert instead. Choose Classes only when you just want the POCOs to paste into an existing DTO folder, and set the namespace so the file drops straight into your solution.

Tips for accurate C# types

Paste the richest sample you can find: include optional fields, empty and populated arrays, and more than one array element so the inference can see which properties are always present. Rename the root class from Root to something meaningful such as OrderResponse before downloading — the file name follows it. After pasting the code into Visual Studio or Rider, review types the sample cannot reveal: an integer ID that may exceed long, a string that is really an enum, or money values that deserve decimal. Everything runs locally, so it is safe to use production responses while you work.