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Senior
Registration: 23.03.2026

Oleksandr Sisov

Specialization: iOS Engineer
— Improved iOS development speed by 40% by integrating an auto-generated REST API layer, reduced module creation time by 80% with an internal CLI tool, and led modular VIPER architecture while mentoring developers. — Built performance-critical mobile solutions including WebRTC streaming with latency under 150 ms and BLE pipelines processing 1M+ events monthly with a 70% sync performance improvement. — Senior iOS Developer specializing in scalable, high-performance mobile applications built with Swift, SwiftUI, UIKit, and modern iOS architecture. — Strong background in fintech, health tech, BLE-enabled apps, offline-first systems, and real-time communication. — Experienced with Clean Architecture, MVVM, VIPER, modularization, Swift Concurrency, Combine, CoreData, REST APIs, testing, CI/CD, and distributed product teams. — In addition, I bring 14+ years of mobile development experience and extensive hands-on experience building products from scratch to MVP. — In most of my roles, I joined at an early stage, took ownership of the initial architecture and feature delivery, helped bring the product to MVP, and then continued scaling it together with a growing team. — Open to fully remote B2B, contract, and freelance opportunities worldwide.
— Improved iOS development speed by 40% by integrating an auto-generated REST API layer, reduced module creation time by 80% with an internal CLI tool, and led modular VIPER architecture while mentoring developers. — Built performance-critical mobile solutions including WebRTC streaming with latency under 150 ms and BLE pipelines processing 1M+ events monthly with a 70% sync performance improvement. — Senior iOS Developer specializing in scalable, high-performance mobile applications built with Swift, SwiftUI, UIKit, and modern iOS architecture. — Strong background in fintech, health tech, BLE-enabled apps, offline-first systems, and real-time communication. — Experienced with Clean Architecture, MVVM, VIPER, modularization, Swift Concurrency, Combine, CoreData, REST APIs, testing, CI/CD, and distributed product teams. — In addition, I bring 14+ years of mobile development experience and extensive hands-on experience building products from scratch to MVP. — In most of my roles, I joined at an early stage, took ownership of the initial architecture and feature delivery, helped bring the product to MVP, and then continued scaling it together with a growing team. — Open to fully remote B2B, contract, and freelance opportunities worldwide.

Skills

Objective-C
SwiftUI
UIKit
Swift
Combine
CoreData
Firebase
WebRTC
MVVM
VIPER
Clean Architecture
Modular Architecture
Swift Concurrency
Fastlane
Jenkins
Bitrise
XCTest
Testing
REST API

Work experience

Senior iOS Developer
02.2025 - 02.2026 |Rakuten Viber
UIKit, Swift, Network
● Develop fintech features for Viber Pay and wallet systems. ● Implemented secure KYC/KYB flows. ● Contributed to modular Swift architecture in distributed teams.
Senior iOS Developer
08.2025 - 12.2025 |Devlight (Health Module)
Swift, Clean Architecture
● Designed modular Swift Package for biometric tracking. ● Integrated BLE devices for real-time data and feedback. ● Built scalable components using Clean Architecture.
iOS Developer
04.2025 - 08.2025 |Software MacKiev
Swift, Objective-C, SwiftUI, UIKit, Combine, CoreData, Firebase, WebRTC
● Refactored legacy codebase and improved stability. ● Fixed critical bugs and improved performance.
Senior iOS Developer
11.2023 - 02.2025 |Mapletton Hill
Swift, Objective-C, SwiftUI, UIKit, Combine, CoreData, Firebase, WebRTC
● Designed offline-first architecture with background sync. ● Optimized large datasets using CoreData and async processing. ● Built map-based UI for data visualization.
iOS Developer
09.2021 - 03.2025 |Andersen Lab
VIPER, REST API, XcodeGen
● Led modular architecture design using VIPER and mentored 2–3 developers. ● Integrated auto-generated REST API layer (+40% dev speed) and reduced merge conflicts via XcodeGen. ● Reduced module creation time by 80% with internal CLI tool.
Senior iOS / Tech Lead
01.2016 - 09.2021 |ZeusElectronics
Swift, Objective-C, SwiftUI, UIKit, Combine, CoreData, Firebase, WebRTC
● Led real-time streaming apps using WebRTC (latency <150ms). ● Processed 1M+ BLE events monthly (+70% sync performance).

Educational background

Computer Science (Bachelor’s Degree)
National Technical University of Ukraine (KPI)

Languages

EnglishIntermediateUkrainianAdvanced