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JSON to Kotlin Data Class Converter Online

Generate Kotlin data classes from JSON instantly. Supports nested JSON, type-safe properties, and Android/Backend Kotlin development workflows.

🔽 JSON Input

JSON

🧾 Kotlin Data Class

KOTLIN

Instant Conversion

Convert your data in real-time as you type. No delays, no waiting.

100% Private

All processing happens in your browser. Your data never leaves your device.

Always Free

No hidden fees, no premium plans. All features are completely free forever.

JSON to Kotlin Class Converter

Easily transform your JSON data into Kotlin classes or data classes. JSON is widely used for API responses, while Kotlin classes allow structured, type-safe data handling in Android or backend projects.

This tool automatically generates nested classes, proper property types, and Kotlin syntax, saving you time and reducing errors compared to manual conversion.

    With this JSON to Kotlin converter, you can:

  • Generate Kotlin data classes from JSON automatically
  • Support nested objects and arrays as inner classes or lists
  • Choose standard classes or Kotlin data classes with default values
  • Copy or download Kotlin models for immediate use in your project

All conversions are performed in your browser. Your JSON data remains private and secure.

What is a JSON to Kotlin Class Converter?

A JSON to Kotlin converter transforms JSON structures into Kotlin classes, mapping keys to properties and arrays to lists or collections.

Manual conversion of JSON into Kotlin classes can be tedious and error-prone, especially with nested objects. This tool automates the process, generating clean, ready-to-use Kotlin code.

    Developers use JSON to Kotlin converters to:

  • Map API responses to Kotlin objects in Android apps
  • Generate type-safe data classes for structured JSON data
  • Accelerate mobile app development and backend services
  • Ensure maintainable and clean Kotlin code

The tool produces classes with proper naming conventions, nested structures, and Kotlin idiomatic syntax.

Why Use Our JSON to Kotlin Converter?

1

Save Development Time

Automatically generate Kotlin classes without writing boilerplate code.

2

Ensure Type Safety

Map JSON types accurately to Kotlin properties for safer, maintainable code.

3

Handle Complex JSON Structures

Nested objects and arrays are converted into inner classes and lists automatically.

4

Quick Integration

Copy or download the generated Kotlin classes and use them directly in Android or backend projects.

5

Data Privacy & Security

All processing happens locally in your browser. JSON data is never uploaded.

When Should You Convert JSON to Kotlin Classes?

1

Android App Development

Map JSON API responses to Kotlin data classes for Android applications.

2

Backend Services

Use Kotlin classes for structured API response handling in backend projects.

3

Nested JSON Data

Automatically handle nested JSON objects and arrays without manual class creation.

4

Serialization & Deserialization

Simplify converting JSON to Kotlin objects and vice versa.

5

Rapid Prototyping

Quickly generate Kotlin models for APIs or sample projects.

Live Example

JSON to Kotlin Class Example

See how JSON data is converted into Kotlin classes automatically.

input.json JSON
output.kt KOTLIN

How JSON Maps to Kotlin Classes

JSON object

→ Kotlin class

Nested object

→ Inner class

JSON array

→ Kotlin list

Key-value pair

→ Class property with type

Automatic mapping ensures structured, ready-to-use Kotlin classes from any valid JSON.

How to Convert JSON to Kotlin Classes Online

1

Paste or Upload JSON

Insert your JSON data. Nested objects and arrays are fully supported.

2

Click Convert

Press Convert to instantly generate Kotlin classes or data classes.

3

Copy or Download Kotlin Classes

Copy the generated classes or download them for use in Android or backend projects.

Pro Tips

  • •Validate JSON before conversion to avoid mapping errors.
  • •Nested objects automatically generate inner classes; review naming consistency.
  • •Use data classes with default values for optional fields.
  • •Integrate generated classes with Kotlin serialization libraries for JSON parsing.
  • •Check nullability for optional or missing fields in JSON.

Frequently Asked Questions

Everything you need to know about JSONtoAll tools.

What is a JSON to Kotlin Data Class Converter?
A JSON to Kotlin Data Class Converter is an online tool that transforms JSON data into structured Kotlin data classes. It automatically maps JSON fields to strongly typed Kotlin properties.
How do I convert JSON to a Kotlin data class?
Simply paste your JSON into the input editor and click convert. The tool instantly generates Kotlin data classes based on your JSON structure.
Does this tool generate Kotlin data classes?
Yes. The converter generates Kotlin data classes using the `data class` keyword with properly typed properties.
Does the tool support nested JSON objects?
Yes. Nested JSON objects are automatically converted into separate Kotlin data classes with proper references.
How are JSON arrays handled in Kotlin?
JSON arrays are converted into Kotlin `List<T>` types. If the array contains objects, a separate data class is generated for the item type.
Are nullable fields supported?
Yes. The tool can generate nullable types (e.g., `String?`, `Int?`) when JSON values may be null.
What Kotlin types are generated from JSON?
The converter maps JSON types to Kotlin types such as String, Int, Double, Boolean, List, and custom data classes for objects.
Can I use the generated Kotlin classes in Android projects?
Yes. The generated Kotlin data classes are fully compatible with Android development and can be used with libraries like Retrofit, Ktor, or serialization frameworks.
Does the tool support large JSON files?
Yes. The converter supports large and complex JSON structures while maintaining accurate type generation.
Is this JSON to Kotlin converter free to use?
Yes. The tool is completely free and works directly in your browser without requiring registration.
Does the tool validate JSON before converting?
Yes. Invalid or malformed JSON is detected automatically to prevent incorrect Kotlin class generation.
Can I convert a single JSON object?
Yes. A single JSON object will generate one root Kotlin data class with corresponding properties.
Are numeric values properly typed in Kotlin?
Yes. Numbers are automatically mapped to appropriate Kotlin numeric types such as Int or Double based on the JSON value.
Is my JSON data uploaded to a server?
No. The conversion happens entirely in your browser, ensuring complete privacy and security.
Can I customize the root class name?
Yes. You can typically specify a custom root class name before generating the Kotlin data classes.
Does the tool generate immutable properties?
Yes. By default, properties are generated using `val` to promote immutability in Kotlin.
What is the difference between JSON and Kotlin data classes?
JSON is a text-based data format commonly used in APIs, while Kotlin data classes are strongly typed models used in Kotlin applications to represent structured data.
Can I use the generated classes with Retrofit or Ktor?
Yes. The generated Kotlin models work seamlessly with Retrofit, Ktor, and other networking libraries.
Does the converter handle Boolean values correctly?
Yes. JSON true/false values are correctly mapped to Kotlin Boolean types.
Why should I use a JSON to Kotlin converter?
Using a converter saves development time, reduces manual coding errors, ensures proper type safety, and speeds up API integration in Android and Kotlin backend projects.

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