JSON to C# Class

Generate C# classes with Newtonsoft.Json attributes from a JSON sample. Handles nested classes, collections, and null fields. Runs entirely in your browser.

Input JSON

C# Class

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Error

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How it works

Paste any valid JSON — classes are inferred from the values: numbers, strings, booleans, arrays, and nested objects.
Whole numbers become int, decimals become double, and null becomes object.
Arrays become List<T>; arrays of objects become List<Type>.
Every property gets a [JsonProperty("...")] attribute so Newtonsoft.Json maps the original key exactly.

Type mapping rules

JSON value	C# type
`42`	`int`
`3.14`	`double`
`"hello"`	`string`
`true` / `false`	`bool`
`null`	`object`
`[1, 2, 3]`	`List<int>`
`[{...}, {...}]`	`List<Type>`
`{"a": 1}`	`class`

About JSON to C# Class

Deserializing JSON in .NET usually means writing POCO classes first, and hand-typing them for a large API response wastes time and invites typos. This tool generates plain C# classes from a JSON sample, complete with [JsonProperty] attributes so property names map back to the original keys — handy when the JSON uses snake_case, kebab-case, or abbreviations that differ from idiomatic C# property names. Nested objects become nested classes and arrays become List<T>.

The output mirrors only what the sample shows: fields missing from the sample are absent from the class, and fields that appear as null become object. After generating, review the result and make value types nullable (int?) where a field can legitimately be absent, or switch to System.Text.Json by replacing the attributes with [JsonPropertyName]. Everything runs on your device, so private payloads stay private.