Compile-time mapper generation for Kotlin Multiplatform, powered by KSP.

Kraft generates type-safe extension functions to map between data classes. No reflection, no runtime overhead — just clean, generated Kotlin code.

data class User(val id: Int, val name: String, val email: String)
data class UserDto(val id: Int, val name: String, val email: String)

@MapConfig(source = User::class, target = UserDto::class)
object UserMapper

// Generated: fun User.toUserDto(): UserDto
val dto = user.toUserDto()

• Automatic property matching — same-name properties mapped without configuration
• Field renaming — @MapField or @FieldMapping for cross-name mapping
• Nested objects — auto-detected when types differ, including renamed properties
• Collections — List<T> and Set<T> with nested element mapping
• Enum mapping — @MapEnum with auto-matching and custom entry pairs
• Custom converters — @MapUsing for property-source or whole-source transformations
• Global converters — @KraftConverter on a top-level extension is auto-discovered across the module and the classpath, with @OptIn markers propagated onto the generated mapper
• Reverse mapping — @MapReverse generates the inverse mapper automatically
• Layer-aware aliases — register Dto / Domain / Entity sides via Gradle to emit short .toDomain() / .toEntity() extensions alongside the verbose mappers
• Ignore rules — @MapIgnore and @MapIgnoreField with directional control
• Configuration objects — @MapConfig for mapping without modifying data classes
• Plugin SPI — implement MapperGeneratorProvider to plug in your own code generator
• Kotlin Multiplatform — annotations work on JVM, iOS, JS, and WasmJs

• Kotlin 2.0+
• KSP (matching your Kotlin version)
• JVM 17+ for the build toolchain (the processor runs at compile time)

// build.gradle.kts
plugins {
    id("com.google.devtools.ksp") version "<ksp-version>"
}

kotlin {
    sourceSets {
        commonMain.dependencies {
            implementation("com.blu3berry.kraft:kraft-annotations:<version>")
        }
    }
}

dependencies {
    add("kspCommonMainMetadata", "com.blu3berry.kraft:kraft-ksp:<version>")
}

// build.gradle.kts
plugins {
    id("com.google.devtools.ksp") version "<ksp-version>"
}

dependencies {
    implementation("com.blu3berry.kraft:kraft-annotations:<version>")
    ksp("com.blu3berry.kraft:kraft-ksp:<version>")
}

• Getting Started
• User Guide
• Architecture & SPI
• AI Integration
• Contributing

Copyright Kraft Contributors

Licensed under the Apache License, Version 2.0

See LICENSE for the full text.