JSON to C# Class

What Is the JSON to C# Class Generator?

The JSON to C# class generator converts a JSON object into ready-to-use C# class definitions. Choose between POCO (Plain Old CLR Object) classes with auto-properties and C# record types with positional parameters. The tool adds [JsonPropertyName] attributes automatically when property names differ from JSON keys.

This tool is useful when building .NET REST clients, scaffolding model classes from API responses, or mapping JSON payloads to strongly-typed C# objects for use with System.Text.Json.

How to Use the JSON to C# Generator

1. Paste your JSON object into the left panel, or click Load Sample.
2. Set the root class name (defaults to Root).
3. Choose POCO class or record mode using the toggle.
4. The generated C# code appears on the right with required using statements.
5. Click Copy to copy all class definitions.

Features

• Generates POCO classes with { get; set; } auto-properties
• Generates C# record types with positional constructor syntax
• Adds [JsonPropertyName("key")] when JSON key differs from PascalCase property name
• Handles nested objects — each becomes a separate named class
• Maps JSON arrays to List<T> with inferred element type
• Type mapping: string → string, boolean → bool, integer → int, decimal → double, null → object?
• Includes using System.Collections.Generic and using System.Text.Json.Serialization
• Configurable root class name

FAQ

What is a POCO class in C#?

POCO stands for Plain Old CLR Object. It is a simple C# class with no framework dependencies. A POCO class typically has public properties with getters and setters, making it straightforward to serialize and deserialize with System.Text.Json or Newtonsoft.Json.

What is a C# record?

C# records are reference types introduced in C# 9 that provide value-based equality and immutability by default. Positional records use a concise constructor syntax and are ideal for DTOs (Data Transfer Objects) because they are immutable and work well with pattern matching.

How are JSON types mapped to C# types?

JSON strings → string, booleans → bool, integers → int, floats → double, arrays → List<T>, objects → named class, null → object?.

Why does the generator add [JsonPropertyName] attributes?

C# property names use PascalCase by convention, but JSON keys often use camelCase. When a JSON key differs from its PascalCase equivalent, the generator adds [JsonPropertyName("originalKey")] so System.Text.Json correctly maps the JSON field during deserialization.