Smartwatch APP Developer (Kotlin / Wear OS and Swift / watchOS)

About UN1Q 
 

UN1Q is a pre-launch startup building an advanced fitness, nutrition, and wellness coaching platform.
 

Our platform delivers structured coaching through personalized exercise, nutrition, and mindset programs, supported by complex rule-based systems, user data, adaptive programming, and increasingly AI-powered functionality.
 

As we expand the UN1Q ecosystem, we are developing dedicated smartwatch applications that will allow users to interact with their training directly from their wearable devices, receive workout guidance, access relevant health and activity information, and synchronize their progress with the wider UN1Q platform.
 

Our technology ecosystem includes:
 

• iOS and Android mobile applications
• PHP/Laravel backend and APIs
• Web platforms and user portals
• Apple watchOS and Google Wear OS applications
• Health and activity data integrations
• AI-powered coaching and recommendation systems
• Cloud infrastructure and third-party integrations.
   

We are seeking an experienced part-time / consultant Smartwatch Developer with experience developing applications across both major smartwatch platforms:
 

• Android: Kotlin / Wear OS
• Apple: Swift / watchOS
   

The primary responsibility of this role is to develop, maintain, and evolve the functional UN1Q smartwatch applications and ensure reliable communication between the smartwatch experience and the main UN1Q mobile application.
 

The underlying interface with smartwatch sensor technology is being developed separately by our engineering team. You will work with this existing sensor/data interface and integrate it into complete, production-ready smartwatch applications.

You will work closely with our Mobile, Backend, Design, QA, and Engineering teams to ensure the smartwatch experience is reliable, intuitive, performant, and properly integrated into the wider UN1Q ecosystem.
 

Key Responsibilities
 

• Design, develop, maintain, and optimize UN1Q smartwatch applications for:
  • Wear OS using Kotlin
  • watchOS using Swift
• Build modern smartwatch interfaces using appropriate native technologies, including Jetpack Compose for Wear OS and SwiftUI for watchOS.
• Integrate the existing sensor/data interface provided by the UN1Q engineering team into the smartwatch applications.
• Implement workout flows including:
  • Workout start, pause, resume, and completion
  • Exercise progression
  • Sets and repetitions
  • Duration and rest periods
  • Timers and workout guidance
  • Display of relevant real-time workout information
• Implement reliable communication and synchronization between the smartwatch applications and the corresponding UN1Q mobile applications.
• Ensure workout state and user actions synchronize correctly between smartwatch, mobile application, and relevant backend services.
• Integrate smartwatch functionality with UN1Q backend APIs where required.
• Implement appropriate offline behavior and synchronization following temporary connectivity loss.
• Handle different connectivity scenarios between smartwatch and mobile devices.
• Implement authentication and secure communication where required.
• Optimize the applications for wearable-specific constraints including:
  • Battery consumption
  • Memory
  • Processing power
  • Background execution
  • Screen size and interaction patterns
• Implement smartwatch notifications, haptic feedback, and appropriate wearable interactions.
• Support background and long-running workout functionality.
• Ensure workout state is preserved reliably when the screen is inactive or the application moves into the background.
• Work closely with designers to implement smartwatch-specific UX rather than simply adapting mobile screens.
• Collaborate with mobile engineers on smartwatch-to-mobile communication and synchronization.
• Collaborate with backend engineers on APIs, authentication, synchronization, and data structures where required.
• Collaborate with the engineer responsible for the sensor interface to correctly consume and present available sensor and workout data.
• Work with QA on testing across supported smartwatch devices and OS versions.
• Troubleshoot device-specific, connectivity, synchronization, and production issues.
• Support application testing, release, versioning, and deployment for both Wear OS and watchOS.
• Maintain clear technical documentation for smartwatch functionality and integrations.
   

Requirements
 

• 3+ years of professional mobile application development experience.
• Strong commercial experience with Kotlin.
• Strong commercial experience with Swift.
• Hands-on experience developing applications for Wear OS.
• Hands-on experience developing applications for Apple watchOS.
• Experience with modern native UI frameworks, including:
  • Jetpack Compose / Compose for Wear OS
  • SwiftUI
• Strong understanding of mobile and smartwatch application architecture and lifecycle.
• Experience implementing communication between smartwatch and companion mobile applications.
• Experience with technologies such as:
  • Wear OS Data Layer APIs
  • Apple WatchConnectivity
  • Background processing
  • Application state management
  • Notifications and haptic interactions
• Experience integrating existing data or sensor interfaces into application functionality.
• Experience integrating applications with REST APIs.
• Strong understanding of synchronization, caching, and offline application patterns.
• Experience handling unreliable or interrupted watch-to-phone connectivity.
• Strong understanding of asynchronous programming.
• Good understanding of battery optimization, memory management, and performance on wearable devices.
• Experience with Android Studio, Xcode, Gradle, Git, and modern mobile development workflows.
• Ability to troubleshoot hardware-, device-, and OS-specific issues.
• Ability to take ownership of smartwatch features from technical implementation through production release.
• Ability to work independently within a part-time / consultancy arrangement.
• Strong communication skills in English.

!Important!
 

This role requires competence across both major smartwatch ecosystems:
 

Android / Wear OS → Kotlin
Apple Watch / watchOS → Swift
 

The underlying interface with smartwatch sensor technology is not the primary responsibility of this role. This functionality is being developed separately by the UN1Q engineering team.
 

The Smartwatch Developer will be responsible for taking the available sensor/data interface and integrating it into a functional, reliable, production-ready smartwatch application that communicates correctly with the main UN1Q mobile application.
 

A good overall understanding of wearable sensors, health/activity data, and their implementation is valuable, as the developer will need to collaborate closely with the engineer responsible for this layer.
 

The Following Will Be Considered an Advantage
 

• Experience with HealthKit and Apple health/fitness integrations.
• Experience with WorkoutKit.
• Experience with Wear OS Health Services.
• Experience with Google Health Connect.
• Experience developing structured fitness or workout applications.
• Experience working with heart rate, activity, workout, or other biometric data.
• Experience with Bluetooth / BLE integrations.
• Experience integrating external fitness sensors or wearable devices.
• Experience with GPS and location-based workout tracking.
• Experience implementing reliable long-running workout sessions.
• Experience with offline-first architectures and conflict-safe synchronization.
• Experience developing companion Android and iOS mobile applications.
• Experience with backend API architecture.
• Experience integrating with PHP/Laravel APIs.
• Experience with AWS or other cloud-connected mobile applications.
• Experience working with fitness, wellness, health, or sports technology.
• Experience publishing Wear OS and watchOS applications to production.
• Experience working in startup or fast-scaling environments.
   

Why Join Us?
 

• Competitive compensation package aligned with your experience, technical expertise, and contribution to the product.
• Join a fast-growing and fast-paced startup environment where you will work across continuously evolving technical challenges.
• Take ownership of a major new part of the UN1Q ecosystem and have real influence over how our smartwatch applications and user experience are developed.
• Work across both major wearable ecosystems - Apple Watch and Wear OS - rather than being restricted to a single platform.
• Work alongside a highly experienced team of senior engineers and technical specialists across backend, mobile, infrastructure, AI, product, and design.
• Work directly with a hands-on CEO who understands the product from start to finish, including its scientific methodology, coaching logic, business requirements, user experience, and long-term vision.
• Work on smartwatch applications directly connected to real exercise programming, user progress, health and activity information, and adaptive coaching.
• Gain exposure to multiple technical domains including Kotlin, Swift, Wear OS, watchOS, mobile applications, APIs, wearable data, cloud systems, and AI-powered coaching.
• Join UN1Q at an exciting stage as we move from pre-launch development into market release, growth, and continued expansion of our wearable platform.