How to Convert JSON to C# Classes (Fast, Free Guide)

If you've ever consumed an API in C#, you've hit this: you have a chunk of JSON and you need matching C# classes to deserialize it into. Doing that by hand is slow and easy to get wrong. Here's how to do it properly — and instantly.

Why you need C# classes for JSON

C# is strongly typed. To work with JSON cleanly, you deserialize it into objects — for example with System.Text.Json or Newtonsoft.Json. That requires classes whose properties match the JSON structure. Get a type or name wrong and deserialization silently fails or throws.

How JSON maps to C# types

The conversion follows simple rules:

• A JSON object becomes a class.
• A JSON string becomes a string property.
• A whole number becomes an int (or long for big values).
• A decimal number becomes a double.
• true/false becomes a bool.
• An array becomes a List of the element type.
• A nested object becomes its own class, referenced as a property.

Property names are converted to PascalCase to match C# conventions (so "first_name" becomes FirstName).

The manual way (and why it's painful)

By hand, you read each field, guess its type, create a class, nest classes for sub-objects, and create List types for arrays. For a large API response with nested data, this takes ages and invites typos — and one wrong type breaks everything at runtime.

The fast way

Our free JSON to C# converter does it instantly. Paste your JSON, choose JSON to C# classes, and get clean, ready-to-use classes — including nested classes and List types. It can also:

• Generate a C# object initializer from your JSON
• Convert XML to C# classes the same way

Everything runs in your browser, so your data stays private.

Tips for clean results

• Use a representative sample. Include all the fields you expect, with realistic values so types are inferred correctly.
• Watch nullable fields. If a value can be missing, consider making the property nullable in your code.
• Rename for clarity. Generated names are a starting point — adjust them to match your domain.
• Keep DTOs separate from your business models for cleaner architecture.

Frequently asked questions

How do I convert JSON to C# classes?

Paste your JSON into a free JSON to C# converter, choose "JSON to C# classes," and copy the generated code.

Can I convert XML to C# classes too?

Yes. Our JSON converter supports XML to C# classes as well.

What library should I use to deserialize JSON in C#?

System.Text.Json (built into modern .NET) or Newtonsoft.Json are both widely used and work with generated classes.

Is it safe to paste my JSON into the tool?

Our converter runs entirely in your browser — nothing is uploaded to a server.

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