Developer Tools
JSON to C# Class Converter
Paste any JSON and get a clean C# class with JsonPropertyName attributes, correct property types, and PascalCase names. OpenToolLab's JSON to C# class converter runs entirely in your browser — nothing is uploaded.
Result
What makes this tool different
System.Text.Json ready
Every property gets the JsonPropertyName attribute so System.Text.Json deserialization works out of the box.
Nested object support
Deeply nested objects become their own classes with descriptive PascalCase names.
List and nullable handling
Arrays become List<T>, and fields that can be null are marked nullable so models match real API responses.
100% in-browser privacy
Type inference happens locally in your browser. Your JSON never touches a server.
About this tool
JSON to C# Class Converter: everything you need to know
C# developers consume JSON everywhere — REST APIs, config files, and webhooks — and the first step is always defining the class that represents the payload. Hand-writing these classes is repetitive, and mismatched property names are a classic source of deserialization bugs. A JSON to C# class converter removes that friction in seconds, and this one does it entirely in your browser.
OpenToolLab's JSON to C# class converter infers the right type for every field. Strings become string, integers become int, decimals become double, booleans become bool, arrays become List<T>, and objects become their own classes. Property names are PascalCase, and each property gets the JsonPropertyName attribute that maps it to the original JSON key — so System.Text.Json deserialization works without extra configuration.
Nested structures are handled by generating a separate class for each level, named from the parent property. A payload with a user object, a posts array, and a tags list becomes a clean set of related classes. Nullable fields are marked with ? so models match real API responses that omit or null out fields.
The converter is part of a multi-language engine, so the same JSON can also generate Go, TypeScript, Dart, Kotlin, or Swift from the same window. Paste your payload once, switch languages with a tab, and copy the output for whichever project you are working on.
Privacy is built into the design. Type inference runs entirely in your browser — your API responses and schemas never leave your device. Open the DevTools Network tab while converting and you will see zero requests.
Use it as part of a real workflow: paste a sample from your API, generate the class, then JsonSerializer.Deserialize<T>(response) into it. You get strong typing, autocomplete, and none of the manual mapping drudgery.
FAQ
JSON to C# Class Converter — frequently asked questions
How do I convert JSON to a C# class?
Paste your JSON into OpenToolLab's JSON to C# class converter and click Generate code. The tool infers each field's type and emits a class with JsonPropertyName attributes — strings, ints, doubles, bools, List<T>, nested classes, and nullable fields included.
Can I use JSON in C#?
Yes. C# has two mature libraries: System.Text.Json (built-in, high performance) and Newtonsoft.Json. Both can serialize and deserialize between JSON strings and your classes. The class definitions this converter generates work with either.
क्या मैं सी # में जेएसओएन का उपयोग कर सकता हूं?
हां, सी # में जेएसओएन का उपयोग किया जा सकता है। System.Text.Json और Newtonsoft.Json दोनों लाइब्रेरी JSON को class objects में बदल सकती हैं। पहले JSON से class generate करें — यह टूल वही करता है — फिर JsonSerializer.Deserialize<T>(json) से डेटा प्राप्त करें।
What is the JsonPropertyName attribute in C#?
It is the System.Text.Json attribute that maps a JSON key to a property with a different name. For example [JsonPropertyName("avatar_url")] on the AvatarUrl property lets it bind to the avatar_url key in your JSON.
How do I handle a JSON array in C#?
Use a List<T> property. For an array of objects the converter emits List<ClassName>, then JsonSerializer.Deserialize<List<ClassName>>(json) fills the whole list from an array payload.
Newtonsoft.Json vs System.Text.Json — which should I use?
For new ASP.NET Core projects, System.Text.Json is the default and fastest choice. Newtonsoft.Json offers more features like flexible handling of dynamic JSON. Both can deserialize the classes this converter generates — with System.Text.Json the JsonPropertyName attribute works out of the box.
How do I deserialize JSON into a C# object at runtime?
Call JsonSerializer.Deserialize<MyClass>(jsonString) from System.Text.Json. The generated class defines the shape; deserialization maps every JSON key to the matching property, including nested objects and List<T> arrays.
What are nullable properties in C# models?
A nullable property (written with a ? suffix, like string? or int?) can hold null. The converter marks fields nullable when the JSON value can be null, so deserializing a missing or null field never crashes your model.
Is the JSON to C# class converter free and private?
Yes. OpenToolLab's JSON to C# class converter is completely free, requires no signup, and processes everything in your browser — your JSON never leaves your device.
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