JSON to Kotlin Converter

Kotlin's data classes are perfectly suited for JSON data modeling — they automatically provide equals(), hashCode(), toString(), copy(), and component functions that Java POJOs require boilerplate code to implement. The AllTools JSON to Kotlin converter generates idiomatic Kotlin data classes with proper type mappings: JSON strings become String, numbers become Int or Double, booleans become Boolean, nullable values become nullable types (String?, Int?), nested objects become separate data classes, and arrays become List<ElementType>. Kotlin's null safety system is leveraged by marking nullable fields with the ? suffix, catching potential NullPointerException issues at compile time rather than runtime. Property names follow Kotlin conventions with @SerializedName or @JsonProperty annotations when the JSON key differs. Default values can be assigned to optional properties, enabling object construction without providing every field. The converter produces code compatible with both Gson (Android's traditional choice) and kotlinx.serialization (Kotlin's own multiplatform serialization library). All generation runs in the browser — your API data stays private.

Kotlin is the primary language for Android development and increasingly popular for backend development with Ktor, Spring Boot, and server-side Kotlin. kotlinx.serialization is Kotlin's built-in multiplatform serialization library — it uses @Serializable annotation and compile-time code generation for efficient serialization without reflection, making it faster than Gson and Jackson on Android. For Android Retrofit API clients, the generated data classes work directly with Gson or Moshi converters for automatic request/response serialization. Kotlin's sealed classes model discriminated unions in API responses — when an API returns different object shapes based on a type field, sealed classes with @JsonSubTypes provide type-safe handling. Kotlin's extension functions can add utility methods to generated data classes without modifying them, keeping the generated code clean while adding application-specific functionality. Kotlin Multiplatform (KMP) projects benefit from kotlinx.serialization classes that work identically across Android, iOS, web, and desktop targets. The AllTools converter produces starter data classes that developers extend with validation, default values, and serialization customizations for their specific API contracts.