JSON to Kotlin
Generate Kotlin data classes from any JSON sample.
Three steps, no reading required.
Paste your input
Drop text, code, or data into the input pane — from an API response, a file, anywhere.
See it process
The result updates instantly as you type.
Copy the result
Grab the output with Copy or Download, or fix the error shown if the input is invalid.
Try it with a sample.
{"id":1,"name":"Ada","active":true,"roles":["admin","user"],"address":{"city":"London"}}Upload & hope
- Sends your input to a server to process it
- Asks for an account after a few free uses
- Limits input size on the free tier
Runs where you are
- Processes everything inside your browser tab
- No account, ever
- No artificial size limit
Questions worth answering upfront.
No. Data classes are generated entirely in your browser. Your JSON is never uploaded, stored, or logged.
kotlinx.serialization. Every class is annotated @Serializable, and a @SerialName is added when the property name differs from the JSON key.
Keys become camelCase properties following Kotlin convention. When the name differs from the JSON key, a @SerialName annotation preserves the original key.
When an array of objects has a key missing from some elements, the property becomes nullable (T?) with a default of null.
Yes. Every tool on DevUtilsNow is free to use with no account required.
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Guides that pair with this tool
How to Generate Kotlin Data Classes from JSON
Turn a JSON sample into Kotlin data classes — camelCase properties, @SerialName, nullable types with defaults, and List for arrays.
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