ToolSink

JSON to C# Class Generator

Turn any JSON payload into strongly-typed C# classes with System.Text.Json attributes — perfect for .NET APIs.

What is the JSON to C# Class Generator?

The JSON to C# Class Generator converts a JSON document into strongly-typed C# model classes ready to paste into your .NET solution. It walks the JSON tree, detects nested objects and collections, and generates one class per type with public properties matching the JSON keys.

It saves .NET developers hours of tedious typing when consuming a new API. Instead of hand-writing 20 DTO classes from a Swagger response, paste the sample JSON and get compilable C# in seconds.

The generation runs entirely in the browser — your JSON is never uploaded, which matters when the payload comes from a private production endpoint.

How to use the JSON to C# Class Generator

  1. 1Paste a representative JSON sample into the input area.
  2. 2Set the root class name (for example, "OrderResponse").
  3. 3Pick options: PascalCase properties, `System.Text.Json` attributes or `Newtonsoft.Json` attributes, nullable reference types.
  4. 4Click "Generate" and copy the produced C# classes.
  5. 5Paste them into your solution.

Key features

  • Automatic nested class detection
  • Configurable naming conventions
  • System.Text.Json or Newtonsoft.Json attributes
  • Nullable reference type support
  • Handles arrays and mixed types
  • Runs offline

Examples

Nested object

Input
{"id":1,"user":{"name":"Ann","roles":["admin"]},"createdAt":"2026-01-05T12:00:00Z"}
Output
public class Root { public int Id { get; set; } public User User { get; set; } public DateTime CreatedAt { get; set; } }
public class User { public string Name { get; set; } public List<string> Roles { get; set; } }

Why use this tool

  • Saves hours of manual DTO writing
  • Produces idiomatic C# with proper types
  • Supports both major JSON libraries
  • Works with any .NET version
  • Your JSON stays private

Common use cases

  • Bootstrapping models for a new API integration
  • Generating DTOs from a Swagger example
  • Creating quick prototypes
  • Teaching JSON structure to junior .NET developers
  • Migrating from JavaScript objects to C# classes

Frequently asked questions

What .NET version is required?

The output is compatible with .NET 6, 7, 8 and newer. Older versions may need small tweaks.

Can I use records instead of classes?

Records are on the roadmap. Currently only classes are generated.

What about inheritance?

The tool generates a flat hierarchy. Complex inheritance is best modelled by hand.

Does it handle polymorphic JSON?

Not automatically. Polymorphic types often need a hand-written converter.

Is my JSON uploaded?

No. All conversion happens in the browser.