Wearables Mobile Engineer

Quick Facts

• Role: Wearables Mobile Engineer (native smartwatch development for watchOS and Wear OS)
• Integration: companion apps connected to an existing React Native app via JSI/Nitro
• Collaboration: fully remote, project-based B2B model with stage-based billing and acceptance protocols

Description

You will analyze and map data flows coming to the watch (training session state, live metrics streams, authorization tokens, hardware telemetry) and define target wearable device coverage (watchOS/Apple Watch versions, Wear OS 5/6, optional Garmin Connect IQ). You will build native companion apps for watchOS (SwiftUI, WatchConnectivity) and Wear OS (Jetpack Compose for Wear OS, Wearable Data Layer API), and create/maintain JSI/Nitro modules that expose watch state back to the React Native layer. You will set quality indicators (battery usage per training hour, BLE reconnection behavior, watch-to-phone latency, background runtime reserves), audit existing JSI/Nitro bridges and Kotlin fitness SDK for reusability, and make architecture decisions for wearables across both platforms.

Responsibilities

• Analyze and map wearable data inputs: training session state, live metrics streams, auth tokens, hardware telemetry
• Define target device matrix and recommend support scope (watchOS + Apple Watch generations; Wear OS 5/6; optional Garmin Connect IQ)
• Define baseline quality metrics for wearable performance (battery drain, BLE reconnection, latency, background runtime reserves)
• Build watchOS companion app using SwiftUI and WatchConnectivity; bridge state to JavaScript via Nitro/JSI
• Recommend Garmin platform support (include/exclude/defer) with cost analysis
• Build and maintain JSI/Nitro modules exposing watch state to the React Native layer
• Build Wear OS companion app using Jetpack Compose for Wear OS and the Wearable Data Layer API
• Audit existing JSI/Nitro bridges and Kotlin fitness device SDK for potential reuse on watches
• Own architecture decisions for wearables on watchOS and Wear OS

Requirements

• 5+ years native mobile development experience (Swift and/or Kotlin) in production projects
• 2+ years delivering native smartwatch apps for end users (watchOS, Wear OS, or both)
• watchOS expertise: Swift, SwiftUI, WatchConnectivity (message/userInfo/file transfer, reachability limits), HKWorkoutSession lifecycle, extended runtime sessions, WidgetKit/complications
• Wear OS expertise: Kotlin, Jetpack Compose for Wear OS, Wearable Data Layer API (MessageClient, DataClient, CapabilityClient), Health Services, Tiles, Watch Face Format, Ongoing Activity (Wear OS 6/6.1, API 36+), Material 3 Expressive
• HealthKit and Health Connect experience for workout data read/write, permission flows, background delivery, and health data privacy requirements
• Bluetooth Low Energy experience: GATT, pairing/bonding, reconnection strategies, background limitations on watch and phone
• Energy and thermal budget management with battery measurements from long training sessions
• Robust phone–watch synchronization design resilient to connectivity loss and supporting data reconciliation
• Ability to work with unreliable sensor data (missing samples, HR artifacts, clock drift)
• Fluent English (written and spoken) for collaboration with US stakeholders in a distributed team

Benefits

• “AI Recruiter” application flow: chat with a virtual recruiter 24/7 during the process
• Project-based collaboration with stage-based billing and acceptance protocols for deliverables
• Flexible B2B cooperation for fitness-tech projects
• Connectis support for administrative and invoicing matters
• Participation in industry events and technology meetups
• Referral bonus: 5,000 PLN
• Fast and remote process
• Final decision made by the Project Owner