Class Name:

Package:

Use Lombok

Nullable Types

JSON Input

Java Output

What is JSON to Kotlin Converter?

Need to generate Kotlin data classes from your JSON (JavaScript Object Notation) data? This tool does that instantly. Perfect for Kotlin developers working with Android, Spring, or Kotlin/JVM who need to deserialize JSON into strongly-typed Kotlin objects. Generate data classes, properties, and type definitions automatically.

According to Kotlin documentation, data classes make JSON processing seamless. Our converter analyzes your JSON structure and generates proper Kotlin data classes. First, validate your JSON using our JSON Validator, then convert it to Kotlin. You can also format your JSON with our JSON Formatter first if needed.

Everything happens in your browser – your JSON never leaves your computer. Convert, download, and use your Kotlin data classes right away.

How to Use JSON to Kotlin

Follow these steps to convert JSON to Kotlin data classes. Each step uses the actual buttons and panels on this page.

Paste, Upload, or Load Sample

Paste your JSON into the left JSON Input panel, or click Upload to load a .json or .txt file. Click Sample to see example JSON. Example input:

{"subscriberId":"SUB-1001","plan":"Unlimited 5G","dataUsage":45.2,"status":"active"}

Invalid JSON will show an error. Use our JSON Validator first if unsure. Configure class name, package, Lombok, and nullable types in the options above.

View Generated Kotlin Output

The right Kotlin Output panel shows the generated Kotlin data classes instantly. JSON objects become data classes, arrays become List<T>.

Download or Copy

Click Download to save the Kotlin file, or Copy to copy to your clipboard. Use Clear on the input panel to start over. All processing runs in your browser.

When You'd Actually Use This

Android Development

Generate Kotlin data classes from JSON API responses for Android apps. Create models for REST APIs or JSON-based configurations. Perfect for Android's JSON processing needs.

Spring Applications

Create Kotlin data classes from JSON data for Spring Boot apps. Generate data models for JSON-based APIs or configurations. Perfect for Spring's Kotlin support.

Kotlin/JVM

Generate Kotlin data classes from JSON data for Kotlin/JVM applications. Create data models for JSON-based APIs or configurations. Perfect for Kotlin server-side development.

Code Generation

Generate Kotlin code from JSON data structures. Perfect for creating data models, DTOs, or entity classes from JSON schemas or API responses.

Common Questions

Is my JSON data stored?

Nope. Everything happens right in your browser. Your JSON never leaves your computer – we don't even see it. Check out the ECMA-404 standard for more details.

How are JSON objects handled?

JSON objects become Kotlin data classes. Properties become data class properties, and nested objects become nested data classes or references. Arrays become List<T>. Check out the RFC 8259 for more details.

Can I use the generated Kotlin code?

Yes. The generated Kotlin code is valid and ready to use. Drop it into your Kotlin project and start using it. You may want to review and refine the data classes for your specific use case.

What about JSON serialization?

The generated Kotlin data classes work with kotlinx.serialization, Gson, or Jackson for JSON serialization. You may need to add serialization annotations for custom property names.

Does it work with large JSON files?

Yep. Since everything happens in your browser, it depends on your device. Small to medium JSON structures convert instantly. Really huge structures might take a few seconds.

What Kotlin version is supported?

The generated code works with Kotlin 1.0 and later. It uses standard Kotlin features and follows Kotlin conventions for maximum compatibility.

Other JSON Tools You Might Need

Conversion is just one JSON task. Here are other tools that work well together:

JSON to Java Converter