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Rostyslav Kryvitchenko

Senior React Native Mobile Developer
Zaporizhia, Ukraine
[open contact info](look above in the "contact info" section) | [open contact info](look above in the "contact info" section)
Telegram: @RostislavK | [open contact info](look above in the "contact info" section)

Summary
Senior React Native Developer with 10+ years in software development, including early
experience as an iOS developer and working with React Native since its initial releases
(2015). Strong background in mobile architecture, native iOS integrations, and high-
performance cross-platform application development. Deep expertise in New Architecture
(Bridgeless, TurboModules, JSI), performance optimization (Reanimated 3, MMKV, React
Query), and full-cycle development — from architecture design to successful App Store
and Google Play publication.

Technical Skills
• Languages: TypeScript, JavaScript (ES6+), Swift, Objective-C
• Mobile Development: React Native (New Architecture, TurboModules, Bridgeless),
Expo, React Hooks
• State Management & Data: Redux (Toolkit, Saga), MobX, React Query, GraphQL
(Apollo), REST API
• Storage & Of ine: Realm, SQLite, AsyncStorage, MMKV
• Performance Optimization: Reanimated 3+, pro ling (Flipper, React DevTools, Xcode
Instruments), memory optimization, FPS stabilization
• Native IOS Integrations:
iOS native modules (Swift), bridging (RCTBridgeModule), deep linking, background
tasks
• Device & Platform APIs:
Push noti cations (FCM), geolocation (foreground/background), permissions, camera,
le system
• Payments:
Stripe, Adyen, Apple Pay, Google Pay
• UI & Animations:
Reanimated, Gesture Handler, Lottie, Rive, Styled Components
• Testing:
Jest, React Native Testing Library
• DevOps & Tools:
CI/CD (Fastlane, GitHub Actions, Bitrise), CocoaPods, Android Pro ler
• Methodologies:
Clean Architecture, SOLID, Agile (Scrum), code reviews
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Work Experience
Private Entrepreneur (Remote) — React Native Developer & Mobile Architect
Remote / Ukraine 2020 – Present

• Improved JS-Native synchronous communication by 45–50% by migrating the
application from the legacy Bridge architecture to the New Architecture (JSI +
TurboModules), eliminating a major bottleneck in data serialization.
• Reduced local data retrieval time by 35% and completely eliminated UI freezes on large
lists by migrating from AsyncStorage to MMKV.
• Decreased redundant network requests by 25% and reduced data latency (TTI) by 15%
by implementing React Query with optimized cache invalidation.
• Led full-cycle development as the main (solo) developer on two complex cross-platform
projects:
• IgniteMobile — medical application for patients (medication tracking, video
consultations, treatment plans).
• B2B e-commerce platform for ordering metal products.
• Acted as Mobile Architecture Consultant on the Coach Packet project — sports live
score and event tracking application.

Light IT — React Native Developer & Mobile Architect
Ukraine 2017 – 2020

• Reduced main screen load time by 35% (from 2.8s to 1.8s) under poor network
conditions by implementing the BFF pattern and aggregating endpoints.
• Improved Realm database performance by 35–40% by implementing indexing and
ef cient predicates, eliminating ANR issues with large data collections.
• Implemented full image upload functionality — users could upload photos to the le
system, save links to Realm database, and display them ef ciently in the app.
• Contributed to the comprehensive redesign of the Busfor mobile app (live on App Store
& Google Play), developing a core stack of screens and reusable UI components to
elevate user experience and application scalability.
• Led a team of mobile developers as Team Lead and Head of Mobile Development
department: conducted code reviews, mentored juniors, performed technical interviews,
and drove technical decisions across multiple projects.
• Served as the main technical expert across projects in various domains (food
marketplace, social network, gym tracking, etc.).
• Implemented advanced features: background geolocation, of ine- rst architecture, real-
time functionality, payments, video calls, and complex navigation with deep linking.
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OpenGeeksLab — React Native Developer
Ukraine 2015 – 2017

• Started career as an iOS developer, building native applications with Swift and
Objective-C before transitioning to React Native in its early releases
• Participated in rewriting the high-traf c theCHIVE iOS app to Swift, engineering key UI
components for post feed screens and multimedia display.
• Developed multiple cross-platform mobile applications from scratch to successful
publication in the App Store and Google Play as a solo developer
• Worked on applications across domains including social networking, language learning,
and service platforms
• Implemented device-to-device communication using Bluetooth and Wi-Fi for data
exchange between mobile devices
• Designed and developed applications with local and cloud data storage, including
synchronization between on-device databases and remote backends
• Developed companion applications for Apple Watch (early versions) and optimized UI/
UX for iPad devices
• Designed and implemented application architecture, navigation, and core features
independently
• Built custom UI components, including an advanced in-app text editor with support for
formatted content and mathematical expressions
• Gained early experience with performance optimization, state management, and native
integrations in React Native

Education
Software development engineer
IT Academy «Step»

Languages
• English – Intermediate
• Ukrainian – Native
• Russian – Native
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