JSON to Kotlin Converter - Generate Data Classes Online

Online JSON to Kotlin Converter: Generate Data Classes Instantly

Speed up your Android and backend development with our JSON to Kotlin converter. In the Kotlin ecosystem, Data Classes are the standard way to model data, but writing them manually for large API responses is tedious. This tool allows you to paste any JSON sample and instantly generate clean, idiomatic Kotlin Data Classes, complete with the necessary annotations for your favorite serialization library.

Why Convert JSON to Kotlin Data Classes?

Kotlin's Data Classes offer a concise way to hold data, but manual mapping is prone to human error, especially regarding null safety.

Leverage Kotlin’s Null Safety

One of Kotlin's best features is its focus on null safety. Our tool analyzes your JSON structure to determine which fields should be nullable (String?) and which are required, helping you avoid NullPointerException at runtime.

Save Hours on Boilerplate Code

For an API response with 50+ fields, writing a Data Class manually can take a long time. Our converter does it in milliseconds, automatically generating properties, nested classes, and the correct data types.

Key Features of Our JSON to Kotlin Tool

Our converter is built to support the modern Kotlin development stack, from Android to Server-side.

1. Support for Major Serialization Libraries

Choose the library you use, and our tool will add the correct annotations:

• Kotlinx.Serialization: Adds @Serializable and @SerialName.

• GSON: Adds @SerializedName.

• Jackson: Adds @JsonProperty.

• Moshi: Adds @Json(name = "...").

2. Recursive Nested Class Generation

If your JSON contains nested objects, our tool doesn't just create an "Any" type. It recursively generates separate Data Classes for each object, maintaining a clean and modular architecture.

3. Smart Type Mapping

The engine accurately identifies types to ensure your code is idiomatic:

• integer → Int or Long

• decimal → Double

• boolean → Boolean

• array → List<T>

How to Convert JSON to Kotlin

1. Paste your JSON: Insert your raw JSON payload into the input editor on the left.

2. Configuration: Enter your Class Name (e.g., UserResponse) and select your preferred Serialization Library.

3. Generate: The Kotlin source code appears instantly in the output window.

4. Copy and Use: Click "Copy" to take the code and paste it directly into your .kt file in Android Studio or IntelliJ IDEA.

Technical Insights: Clean Kotlin Code

Naming Conventions

JSON keys often use snake_case, while Kotlin prefers camelCase. Our tool automatically converts keys to idiomatic Kotlin property names while using library-specific annotations to ensure the mapping remains correct during parsing.

Handling "var" vs "val"

By default, the tool generates val properties to encourage immutability, which is a core best practice in Kotlin development. This ensures your data models are thread-safe and easier to reason about.

Frequently Asked Questions (FAQ)

Is this tool compatible with Android Studio?

Yes! The code generated follows standard Kotlin syntax and works perfectly in Android Studio, IntelliJ IDEA, and any other Kotlin-supported IDE.

Does it support the Parcelable interface?

While the tool focuses on data structure, the generated classes are clean and ready for you to add the @Parcelize annotation if you are developing for Android.

Is my JSON data secure?

Absolutely. All conversion logic is performed locally in your browser using JavaScript. Your JSON data is never sent to our servers, ensuring your API structures remain private.