Ostap Marchenko

iOS & Flutter Developer
Lviv, UA.

About

As an experienced mobile developer, I bring over 7 years of commercial experience in building native iOS applications and 2+ years in cross-platform development with Flutter. My specialization is designing and implementing complex, high-performance, and scalable solutions, from SaaS platforms to consumer-focused applications.
I focus on writing clean, efficient, and maintainable code, applying best architectural practices (MVVM, VIPER, Clean Architecture). My approach involves a deep understanding of the client's business goals to create products that not only work flawlessly but also provide real value to the end-user.
My Upwork experience, confirmed by Top 10% Talent status and a 100% Job Success Rate, demonstrates my reliability and results-driven mindset.

Skills

Languages & Frameworks

Swift, SwiftUI, Objective-C, Flutter.

Architectures & Patterns

MVVM, MVC, VIPER, MVP, Clean Architecture.

Platforms & Tools

Xcode, WatchOS, Firebase, TestFlight, App Store Connect, Git.

APIs, SDKs & Databases

REST API, JSON, CoreData, WebSockets, AVFoundation, Push Notifications.

Payments & Maps

Stripe, PayPal, Google Maps, MapBox.

Integrations

Social Media (Facebook, Google), In-App Purchases, HealthKit.

Mobile Development

iOS Development, Cross-Platform Development, Full-Cycle Development, UI/UX Implementation, API Integration, Debugging, Code Refactoring, Performance Optimization, App Store Deployment.

Software Engineering

Scalable Solutions, High-Performance Systems, Clean Code, Maintainable Code, Architectural Design, Problem Solving, System Design.

Project Management & Collaboration

Cross-functional Collaboration, Requirements Gathering, Client Management, Technical Leadership.

Work

Freelance
|

Flutter Developer

Remote

Summary

Specialized in cross-platform development using Flutter, building applications for iOS and Android from a single codebase, managing the full development lifecycle from UI/UX to API integration and publishing.

Highlights

Engineered and deployed robust cross-platform mobile applications for iOS and Android using Flutter, leveraging a single codebase for enhanced development efficiency and maintainability.

Managed the complete application development lifecycle, encompassing intricate UI/UX implementation, seamless API integration, and successful publishing to both App Store and Google Play.

NerdzLab
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iOS Developer

Lviv, Ukraine

Summary

Full-cycle development of native iOS applications for SaaS, Healthcare, E-commerce, and Wellness sectors, from requirements gathering and design to deployment and optimization.

Highlights

Directed end-to-end development of native iOS applications, overseeing requirements analysis, architectural design, development, rigorous testing, and successful App Store publication.

Optimized performance, resolved critical bugs, and refactored existing application code, enhancing stability and user experience across diverse industry verticals including SaaS and Healthcare.

Implemented complex, pixel-perfect UI/UX designs, ensuring high fidelity to specifications and delivering an excellent, intuitive user experience.

Collaborated cross-functionally with project managers, designers, and backend developers to align technical solutions with strategic business objectives and deliver impactful products.

CyberChisel
|

iOS Developer

Ukraine

Summary

Contributed to the development and maintenance of iOS applications for company clients, focusing on clean code implementation and feature delivery according to technical specifications.

Highlights

Participated in the development and maintenance of client-facing iOS applications, ensuring strict adherence to technical specifications and coding standards.

Implemented new features and functionalities, prioritizing clean, modular, and maintainable code to support project scalability and long-term stability.

2Event
|

iOS Developer

Summary

Developed and updated core functionality for an event platform, enhancing user interaction and integrating critical third-party APIs and push notification systems.

Highlights

Developed and updated key functionalities for an event management platform, significantly improving user interaction and overall engagement.

Integrated critical third-party APIs and implemented a robust push notification system to enhance real-time communication and user experience.

Projects

Hubmee

Summary

Played a key role in developing the iOS client for Hubmee, a comprehensive organizer acting as a "personal manager" for the user. I was responsible for implementing calendar, notes, tasks, chats, AI integration, and finance features. The project involved creating a complex document manager (finance, insurance, auto, health, work) and a reliable reminder and planning system.

Social & Puzzle Games

Summary

Developed a series of mobile games, demonstrating experience in game logic and real-time interaction: Mafia, Werewolf, Avalon, Resistance: Created client-server games for groups. The key challenge was implementing stable and fast game state synchronization among all players via WebSockets. WordDuo: Developed a fast-paced micro-puzzle game optimized for short game sessions and immediate engagement.

Construction Clock

Summary

Created a GPS time tracker aimed at construction companies. The app automates report submission and schedule management, using background geolocation services for accurate time tracking on-site. This allowed business owners to optimize document flow and payroll calculations.

RASHAKA

Summary

Participated in the development of a personal wellness guide. The app provides users with personalized recommendations by analyzing input data (weight, activity). I was responsible for integrating with HealthKit to collect and synchronize health data, ensuring accurate progress tracking.

WHATSALON & WHATSALON GO

Summary

Developed an ecosystem of two apps: a B2C marketplace for clients (search, reviews, booking) and a B2B tool for salon owners. The B2B app included complex logic for managing bookings, a client base, and integration with Stripe/PayPal payment systems.

Truvay

Summary

Developed an app for social rating of places (restaurants, attractions) worldwide. Implemented complex map interaction (MapBox/Google Maps), search by categories, and a system for creating, viewing, and rating user-generated content (ratings, comments).

Education

Rzeszów University of Technology (POLITECHNIKA RZESZOWSKA)
Rzeszów, Subcarpathian Voivodeship, Poland

Engineer

Logistics

Languages

Ukrainian
English
Polish