JSON code generation / Kotlin

Free online JSON to Kotlin data class generator

Generate data classes for a profile with a nullable avatar. Open your JSON locally, then inspect and download the generated files.

Privacy-first processing: pasted or opened JSON stays in this browser tab and is not uploaded to our servers.

Target: KotlinChoose serializer and model options in the workbench

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Try the profile card example

The editor starts empty. Load this example only if you want a small source to test the generated model.

Static example with expected output

Verified with the local schema-codegen engine.

Profile JSON

{
  "user_id": 42,
  "display_name": "Mina",
  "avatar": null,
  "badges": [
    "editor",
    "mentor"
  ]
}

Operation

Generate Kotlin data classes and enum candidates from repeated strings.

Language: Kotlin
Serializer: none
Style: data class
File layout: split files

Expected output excerpt (GeneratedRoot.kt)

data class GeneratedRoot(
    val avatar: Any?,
    val badges: List<GeneratedRootBadgesItemEnum>,
    val display_name: String,
    val user_id: Long
)

Caveat: The avatar field is Any? because the sample has null and no non-null value to infer.

Before using this output

Nullability is sample-inferred, deserialization is separate, and separate files avoid the current single-file import-order limitation.

Generation analyzes the source shape; it does not validate every future input. Review the language, serializer, enum, primitive, and file-layout options before downloading.

Read the Kotlin workflow

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