JSON to C# Class Generator Online — Free C# Model Generator
JSON to C# Class
Convert JSON to C# classes with System.Text.Json or Newtonsoft serialization.
Free online JSON to C# class generator. Paste any JSON object and get C# class or record definitions with [JsonPropertyName] or [JsonProperty] attributes, nullable reference types, PascalCase property names, List<T> for arrays, and DateTime for date strings. Supports both System.Text.Json and Newtonsoft.Json. Perfect for .NET developers building API models. Runs entirely in your browser.
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Tags: json, csharp, dotnet, class, model, converter, generator
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How to JSON to C# Class Online
Paste valid JSON into the input area on the left.
Set the root class name (defaults to 'Root') using the option field.
Choose the serializer: System.Text.Json or Newtonsoft.Json (Json.NET).
Toggle record types (C# 9+) and nullable reference types to match your project settings.
Click Convert or press ⌘↵ (Mac) / Ctrl+Enter (Windows) to generate C# classes.
Copy the generated C# code or download it as a .cs file.
JSON to C# Class Features
Generates C# classes or records from any JSON object or array.
Supports nested objects — creates separate named classes for each nested structure.
System.Text.Json mode: uses [JsonPropertyName] attributes.
Newtonsoft.Json mode: uses [JsonProperty] attributes.
Optional record types (record class) for immutable C# 9+ data models.
Optional nullable reference type annotations (string?, int?, etc.).
Smart type inference: string, int, double, bool, List<T>, and nullable variants.
Works entirely in your browser — JSON never leaves your device.
Keyboard shortcut ⌘↵ for instant conversion.
Frequently Asked Questions
- What is JSON to C# class conversion?
- JSON to C# generates C# class definitions from a JSON sample, complete with serialization attributes. Instead of writing model classes by hand, paste your API response and get strongly-typed C# code ready for use with System.Text.Json or Newtonsoft.Json.
- Should I use System.Text.Json or Newtonsoft.Json?
- System.Text.Json is the built-in .NET serializer (no extra packages) and is preferred for new .NET 6+ projects. Newtonsoft.Json (Json.NET) is the classic library with more features and is still widely used in existing codebases. Choose whichever your project already uses.
- What are C# record types?
- Records (introduced in C# 9) are reference types with built-in value equality, immutability via init-only properties, and a concise syntax. They are ideal for modelling API response payloads that should not be mutated after deserialization.
- Is my JSON data safe?
- All conversion runs in your browser using pure JavaScript. No JSON is ever sent to a server. Your data stays completely private.
- Can it handle nested JSON?
- Yes. Each nested JSON object becomes its own C# class. The parent class references the child class by name, and all classes are output together in the same file.
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