Senior Kotlin Multiplatform Engineer - YOnC SDK

Role Description

Yo is building an AI inference platform that runs directly on smartphones - turning the phone in your pocket into part of a global AI network. The mobile SDK that ships this to Android and iOS devices is moving to a shared core built in Kotlin Multiplatform, replacing what was previously two separate native codebases. This is a foundational hire on a KMP effort that is just getting started. You will help build the shared core from the ground up and shape its public API alongside the existing Android and iOS engineers.

• Build and maintain the KMP shared core: business logic, state machines, and data models used by both the Android and iOS clients
• Design the shared module's public API - decide what it exposes to platform-specific code and what stays internal
• Keep the shared module platform-clean: no Android-only imports, plain data classes and suspend functions at the platform boundary
• Wire up dependency injection using Metro (a newer DI tool similar to Dagger/Anvil)
• Package the iOS side as an XCFramework and handle Kotlin/Native interop correctly for Swift consumers
• Build and maintain a Jetpack Compose benchmark app on Android used to validate the shared core
• Work with the Android and iOS engineers to migrate their existing native code onto the shared core

Qualifications

• Production experience with Kotlin Multiplatform: shared module design, expect/actual, judgment on where platform boundaries belong
• Experience building and shipping an SDK or library consumed by other developers - deciding what belongs in a public API and what stays closed
• Dependency injection experience (Dagger, Anvil, Hilt, Koin, or similar); able to pick up Metro quickly
• Working knowledge of Swift and iOS development, including how Kotlin/Native interop and Objective-C/Swift bridging work
• Jetpack Compose experience
• Strong Kotlin fundamentals: coroutines, suspend functions, structured concurrency

Requirements

• Nice to Have: Compose Multiplatform experience - not needed now, but a likely future direction
• Familiarity with Kotlin/Native specifics: memory model, concurrency constraints, interop edge cases
• Android or iOS production experience beyond KMP itself
• On-device AI / ML experience

What Success Looks Like (First 6 Months)

• Shared KMP core in production use by both the Android and iOS clients
• Clean, reviewed public API for the shared module
• Android and iOS native code migrated onto the shared core
• Working Compose benchmark app used to validate changes to the core

Location & Logistics

• Remote / flexible
• Reports to the CTO