Use the free JSON to C# Classes below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
Turn JSON Into C# Classes Without the Typing
Every .NET developer knows this job. An API returns JSON, and before you can use it you need classes with the right properties and the right types. Doing it by hand means reading the document line by line, deciding each type, and writing property after property. It is boring work, and boring work breeds mistakes: a property spelled slightly wrong, a number typed as int when it sometimes arrives as a decimal, a nested object flattened by accident. This tool does the mechanical part for you and leaves the judgment calls to you.
Paste the JSON, name the root class, and press Convert. The output is a set of C# classes with auto-properties, the familiar get and set pattern. Text becomes string, whole numbers become int, decimals become double, true and false become bool, and arrays become List of the element type. Nested objects become their own classes, named after the field that contains them.
How Properties Are Named
C# convention puts property names in PascalCase, and the tool follows it. A JSON key like zipCode becomes ZipCode. A key like zip_code becomes ZipCode. A key like orderId becomes OrderId. This matches what most .NET developers expect when they read a model class, and it matches the default behavior of the common JSON libraries when they map between naming styles.
One detail matters here. System.Text.Json and Newtonsoft.Json handle case-insensitive matching in many setups, but with strict settings a property that differs from the JSON key needs a JsonPropertyName or JsonProperty attribute. Property names here are the PascalCase form of the keys, so adding an attribute is a one-line change when you need it.
Types, Lists, and Nulls
The type rules are deliberately conservative. A whole number becomes int, because that is what most JSON integers are in practice. A decimal becomes double. A string stays a string even when it looks like a number, since the tool cannot know whether “1024” is meant to be text or a number, and treating text as a number would corrupt data. If your API sends numeric ids as strings, keep them as strings and convert them where you use them.
Arrays become List types. An array of strings becomes List of string. An array of objects becomes a list of a new class, singularized from the field name, so orders produces an Order class. An empty array becomes a list of object, because an empty sample says nothing about what the array will contain later. A field whose value is null becomes object for the same reason. These are the two places where you must apply your own knowledge: look at the API documentation, decide the real type, and edit those two spots.
Using the Output in a Real Project
Copy the generated classes into a Models folder or wherever your project keeps its data types. The output already includes the using statement for generic collections, so List works without extra imports. Then wire the classes to your HTTP code. With System.Text.Json, deserialize with JsonSerializer.Deserialize of your root type. With Newtonsoft.Json, use JsonConvert.DeserializeObject. Either way, test with a real response before you trust the model.
Test with more than one response. APIs vary. One user may have no orders, another may have ten. One product may have a discount, another may not. A field that is always present in your first sample may be missing in the second, and a field that is null in your first sample may carry a value in the second. Convert the fullest response you can find, and then check the model against a second, different response to catch the variations.
When you find a variation, fix the model, not the JSON. If a price sometimes arrives as a string, change the property to string and parse it in your code. If an id sometimes exceeds the int range, change it to long. If a field is sometimes missing, make the property nullable. These are small, deliberate decisions, and they are much easier to make when the bulk of the model is already written for you.
Nested Data Done Right
Nested objects are where hand-written models go wrong most often. It is tempting to flatten an address into the user class, or to store a nested object as a raw string. The tool does neither. Each nested object gets its own class, and each array of objects gets a list of its own class. The result reads like a proper domain model: a User has an Address, a User has a list of Orders, and each Order has its own fields.
If two fields would create classes with the same name, the tool numbers the later one. This keeps the output compiling instead of failing with a duplicate type error. Rename the numbered class to something meaningful once you see what it represents. A name like Address2 is a signal to you, not a final answer.
Privacy
The conversion runs entirely in your browser. Nothing is uploaded and nothing is stored. You can safely convert responses that contain real customer data, although as a habit you should still avoid pasting access tokens or passwords into any web page. The tool is free, needs no account, and works with JSON of ordinary API size.