How does the tool name the C# properties?

JSON keys are converted to PascalCase C# property names, for example first_name becomes FirstName. If the converted name differs from the original key, a JsonPropertyName attribute is added above the property so System.Text.Json still maps it correctly.

What C# types does it use for numbers and strings?

Strings map to string, whole numbers map to int (or long for values outside the 32-bit range), decimal numbers map to double, and booleans map to bool.

How are nested objects handled?

Each nested object gets its own named class, generated from the property name (for example address becomes an Address class), and the parent property uses that class as its type.

Can I generate records instead of classes?

Yes. Check "Generate as record" to output C# 9+ record types with init-only properties instead of a mutable class with get; set; accessors.

What happens with an array of objects that have different fields?

The tool scans every item in the array and includes every property it finds across all items in the generated class, so no field is silently dropped.

Is my JSON sent to a server?

No. Parsing and code generation run entirely in your browser with plain JavaScript. Your data never leaves your device.

JSON to C#

Paste JSON and instantly get matching C# class definitions with public properties and nested classes.

Input JSON

Root class name

Generate as record (C# 9+)

Add [JsonPropertyName] attributes

C# Output

Paste JSON and click Generate

Copied!

Summary

JSON to C# reads a JSON value and generates matching C# class definitions, including public auto-implemented properties and separate classes for nested objects. When an array of objects is scanned, properties are gathered across every item so the generated class covers keys that only appear on some entries. Property names are converted to PascalCase and a JsonPropertyName attribute is added whenever the property name differs from the original JSON key, so System.Text.Json can still deserialize the original payload correctly.

How it works

Paste or type JSON into the input panel, or load a sample.
Set a root class name (defaults to RootObject).
Click Generate to parse the JSON and build C# classes.
Nested objects become their own named classes; arrays of objects are scanned across all items to collect every property.
Review the generated classes, each with public auto-properties, in the output panel.
Click Copy to copy the C# code to your clipboard.

Use cases

Scaffold a POCO for an incoming REST API response before writing a deserializer.
Turn a sample config file into a typed C# settings class.
Generate a starting class for System.Text.Json or Newtonsoft.Json without typing every property by hand.
Document a third-party API response shape as C# types.
Speed up building a .NET client for an API that only ships JSON examples.
Check property naming and nesting before hand-writing a data model.

Frequently Asked Questions

Last updated: 2026-07-13 · Reviewed by Nham Vu