09/11/2026 updated
100 % available
Senior iOS Engineer | Swift 6, SwiftUI/UIKit | Architecture & SDKs
Rijeka, Croatia
Worldwide
MSc in Computer Science, Cherkasy State Technological University (2002-2007)About me
I build iOS products that need to stay reliable as they grow. I enjoy solving architecture, concurrency and debugging problems, working closely with product teams, and leaving codebases easier to change. Outside client work, I write about Swift internals and maintain open-source Swift packages.
GitHub ActionsLLMApple IOSApple XcodeUnit TestingBluetooth Low Energy (Bluetooth)Mobile Application DevelopmentContinuous IntegrationDependency InjectionIOS SDKObjective-C (Programming Language)Software ArchitectureAdvanced Encryption Standard (AES)UikitTest-Driven Development (TDD)
Senior iOS Engineer with 10+ years of experience building and modernizing production iOS applications and reusable SDKs. I work with Swift, Objective-C, SwiftUI, UIKit and Swift 6 strict concurrency, and I can take ownership from architecture and technical planning through implementation, testing and release.
Core iOS expertise:
• Swift, Objective-C, SwiftUI, UIKit, Combine, RxSwift
• Swift Concurrency, async/await, actors, Sendable, GCD
• Modular applications and SDKs, Clean Architecture, MVVM-C, Coordinator, dependency injection
• REST APIs, Server-Sent Events, Core Data and offline-first data flows
• TDD, XCTest, unit, integration, snapshot and UI testing
• GitHub Actions, Bitrise, Fastlane, Jenkins, TestFlight and App Store delivery
Specialist experience:
• HealthKit, CoreBluetooth, CoreLocation and connected-device applications
• Secure data handling, Keychain, encryption and certificate pinning
• Kotlin Multiplatform integration and native platform adapters
• Hosted LLM API integration and streaming-response interfaces
• Performance profiling, debugging and incremental modernization of mature codebases
My recent work includes zero-to-one product development, ownership of iOS architecture for a confidential pre-launch product, and modular healthcare software used at scale. I also write hands-on articles about Swift internals and runtime behavior at dementievmykola.com.
Based in Rijeka, Croatia. Available for remote full-time or long-term contract work from late September 2026.
Experience
Professional experience10+ years
Freelancer since2016
Languages
GermanGoodEnglishFluentRussianFluentUkrainianNative speaker
Project history
Founding engineer for a confidential pre-launch AI product.
• Own iOS architecture and technical direction from the first commit using Swift 6 strict concurrency and SwiftUI.
• Integrate hosted LLM APIs and streaming responses into the iOS application.
• Build automated unit and snapshot test suites with TDD.
• Maintain GitHub Actions build and test pipelines.
Senior iOS Engineer for a confidential health-tech product.
• Designed and delivered a reusable modular iOS SDK with Clean Architecture and dependency injection.
• Built SwiftUI features using Combine and MVVM-C.
• Integrated REST and Server-Sent Events APIs.
• Established automated build and test pipelines in GitHub Actions.
• Maintained unit, integration, snapshot and UI test coverage across regular releases.
Worked on a modular iOS and SDK ecosystem for healthcare applications and partner integrations used by more than 1M patients and caregivers.
• Designed reusable SDK components for document exchange, HealthKit synchronization, notifications and validation.
• Built server-configured HealthKit synchronization that supported additional metrics without an app release.
• Implemented secure on-device document handling with encryption and certificate-pinned networking.
• Contributed native iOS adapters for shared Kotlin Multiplatform business logic.
• Improved automated testing and Bitrise CI/CD workflows.