JSON Formatter & Model Generator

Format JSON and generate Swift Codable structs or Kotlin data classes from the same input.

Input JSON

Output

About This Tool

A secure, browser-based JSON utility for formatting API payloads and generating mobile app model code without sending any data to a server.

Input

Paste practical JSON from real development work

JSON, short for JavaScript Object Notation, is a lightweight data format used to exchange structured data between apps, APIs, backend services, and development tools. It is easy for humans to read and easy for software to parse, which is why it appears in REST APIs, debug logs, configuration files, and mobile app networking layers.

This tool accepts normal JSON as well as escaped or double-encoded JSON strings such as "{\n \"date\" : \"2026-05-29\" \n}". You can paste those strings directly, then decode and format them without manually removing slashes or line-break escapes.

For iOS development, this is useful when Xcode prints raw request or response JSON in the console. Paste the log output as-is, format it instantly, and inspect the payload before creating Swift models or debugging API issues.

Output

Generate readable JSON and mobile models

JSON Format

Format compact or messy JSON into a readable 2-space indentation style. Nested objects and arrays become easier to scan, compare, copy, and share during API debugging.

Swift Codable

Generate Swift structs that conform to Codable for iOS and macOS development. Nested objects become nested struct definitions, arrays are mapped to Swift array types, and null values are represented as optional properties with ? where needed.

Kotlin data class

Generate Kotlin data classes commonly used in Android development. Arrays are mapped to List types, nested objects become separate data classes, and null values are represented with nullable types using ? automatically.