Alexander Zakalsky

Alexander Zakalsky

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React Native & Full-Stack Developer | TypeScript, React native, Node.js | 2M+ Users Shipped | Cross-Platform iOS & Android | Open to Remote (EU/US/LATAM)
Punta del Este, Maldonado Department, Uruguay
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Jobs verified_user 0% verified
  • AION Biosystems
    Lead Mobile Engineer
    AION Biosystems
    Dec 2025 - Current (11 months)
    Building Aion Tempshield app

    AION TempShield: FDA-cleared skin wearable that tracks body temperature continuously for up to 60 days, used by oncology patients between chemovisits.
    - Own the iOS and Android app end to end: BLE pairing with the patch, reading pipeline, threshold alerts, care-team sharing, store releases.
    - Built offline-first sync on WatermelonDB with native BLE and background modules in Kotlin and Swift, so a patient's readings hold through hours without signal and upload in batches once the phone reconnects.
    - Integrated BP and SpO2 monitors plus a Moko BLE gateway for home setups

  • AION Biosystems
    Lead Mobile Engineer
    AION Biosystems
    Dec 2025 - Sep 2026 (10 months)
    AION TempShield, an FDA-cleared, HIPAA-compliant skin-worn sensor tracking body temperature continuously for up to 60 days.
    • Owned the iOS and Android application end to end: BLE pairing with the patch, reading pipeline, threshold alerts, care-team sharing and store releases
    • Built offline-first sync on WatermelonDB with native BLE and background modules in Kotlin and Swift, holding readings through hours without signal and uploading in batches on reconnect
    • Integrated blood-pressure and SpO2 monitors plus a Moko BLE gateway for home setups
    • Live on both stores: Google Play us.aion.biosystems, App Store id1605962988
  • Social Discovery Group
    Senior React Native Developer
    Social Discovery Group
    Jan 2024 - Dec 2025 (2 years)
    Ten or more cross-platform projects in the social discovery space, each serving 5,000+ monthly active users, in a single monorepo.
    • Achieved 70 percent faster screen-load times by restructuring architecture with code splitting, lazy loading and render optimisation, measured with the Hermes profiler
    • Reduced production crash rate to 0.1 percent with Sentry and Crashlytics, clearing a backlog of 200+ issues and adding automated regression testing
    • Improved delivery efficiency 20 percent through CI/CD with Fastlane, GitHub Actions and CodePush
    • Led the state management migration from Redux to Zustand, reducing boilerplate by 40 percent
    • Bridged native iOS and Android modules for biometrics with Face ID and Touch I
  • Social Discovery Group
    Senior React native developer
    Social Discovery Group
    Jan 2024 - Dec 2025 (2 years)
    Senior React Native Developer working across 10+ cross-platform mobile projects in the social discovery and dating space, each serving 5,000+ monthly active users.

    Key achievements:
    - Achieved 70% faster screen load times by restructuring React Native architecture with code splitting, lazy loading, and render optimization (React.memo, useMemo, useCallback)
    - Reduced production crash rate to 0.1% through Sentry error tracking, Crashlytics monitoring, and automated regression testing with Jest and Detox
    - Improved delivery efficiency by 20% through CI/CD pipeline optimization (Fastlane, GitHub Actions, CodePush OTA updates)
    - Led state management migration from Redux to Zustand, reducing boilerplate by 40%
  • Chiliz
    Senior React Native Developer, Contract
    Chiliz
    Aug 2023 - Dec 2023 (5 months)
    Socios.com, a Web3 fan-engagement platform with 2M+ registered users, across React Native mobile and React.js web codebases.
    • Developed front-end components for web and mobile contributing to the platform’s 2M+ user base and its crypto wallet integration
    • Drove MVP completion with the highest velocity across all teams using TypeScript, Redux Toolkit, GraphQL with Apollo Client and WebSocket real-time data feeds
    • Implemented push notifications through FCM and APNs plus deep and universal linking, increasing daily active users by 15 percent
    • Live on Google Play as com.socios with 1M+ downloads
  • Chiliz
    Senior React Native Developer
    Chiliz
    Aug 2023 - Dec 2023 (5 months)
    Senior React Native Developer on the Socios platform — a Web3 fan engagement app with 2M+ registered users. Worked across both React Native (mobile) and React.js (web) codebases.

    Key achievements:
    - Developed front-end components for the Socios web and mobile app, contributing to the platform's 2M+ user base and Web3/crypto wallet integration
    - Drove MVP completion with highest velocity across all teams using TypeScript, Redux Toolkit, GraphQL (Apollo Client), and WebSocket real-time data feeds
    - Implemented push notification system (FCM/APNs) and deep linking / universal links, increasing daily active users by 15%
    - Built reusable component library with Storybook documentation, accelerating feature developmen
  • C
    React Native Developer, Full-Stack
    ClinicSoftware
    Dec 2021 - Jul 2023 (1 year 8 months)
    Sole frontend engineer on a healthcare mobile application taken from zero to MVP, with full-stack responsibility for API design and infrastructure.
    • Designed the full-stack data layer for GDPR-compliant patient records: Node.js and Express REST API on PostgreSQL, JWT authentication, OAuth 2.0 and encrypted transport
    • Implemented offline-first architecture with background synchronisation for clinicians working without connectivity
    • Built identity verification through the device camera with OCR and a third-party KYC provider
    • Set up CI/CD with GitHub Actions, Fastlane, Jest and Detox, reducing manual QA effort 30 percent
    • Mentored 2 junior developers to mid-level through code review and pair programming
  • ClinicSoftwarecom CRM Clinic Software Salon Software Spa Software
    React Native Developer
    ClinicSoftwarecom CRM Clinic Software Salon Software Spa Software
    Dec 2021 - Jul 2023 (1 year 8 months)
    Sole frontend developer who architected and built a healthcare mobile application from zero to MVP, with full-stack responsibilities including backend API design and infrastructure.

    Key achievements:
    - Architected the entire React Native app from scratch using TypeScript, React Navigation, and MMKV for secure local storage
    - Designed full-stack data layer: Node.js/Express REST API with PostgreSQL, JWT authentication, OAuth 2.0, and encrypted communication for HIPAA-compliant patient data
    - Implemented offline-first architecture with background data synchronization for clinicians working without connectivity
    - Mentored 2 junior developers to mid-level through code reviews, pair programming, and technical docume
  • C
    Full-Stack Developer
    Complex Cloud Solutions
    May 2021 - Dec 2021 (8 months)
    • Built a performant photo editor with gesture-driven animations using Reanimated and Gesture Handler, holding 60 FPS on both platforms
    • Developed an end-to-end payment system on Node.js, Express, PostgreSQL and React Native, integrating 2 point-of-sale systems (iiko, R-Keeper) over REST and webhooks
  • C
    Full-stack Developer
    Complex Cloud Solutions
    May 2021 - Dec 2021 (8 months)
    Full-stack React Native developer responsible for building multiple apps from concept to App Store/Google Play publication, including a photo editor app and a restaurant payment platform (OMG app).

    Key achievements:
    - Built performant photo editor with gesture-driven animations using React Native Reanimated and Gesture Handler, achieving 60 FPS on both platforms
    - Developed end-to-end payment system: Node.js/Express backend with PostgreSQL, React Native frontend with Redux, integrating restaurant POS systems (iiko, R-Keeper) via REST APIs and webhooks
    - Published apps on App Store and Google Play, managing code signing, provisioning profiles, and the full review process
    - Implemented internationalization (i18n
  • T
    React Native Developer
    Tiande
    Sep 2019 - May 2021 (1 year 9 months)
    React Native developer for the TianDe e-commerce mobile app (100K+ installs across iOS and Android). Led full legacy codebase rewrite and delivered key product features over a 2-year tenure.

    Key achievements:
    - Led full rewrite from legacy codebase to modern React Native: TypeScript, functional components, React Hooks, React Navigation v5
    - Shipped offline mode (AsyncStorage + SQLite), push notifications (FCM/APNs), in-app purchases (StoreKit, Google Play Billing), and geolocation services
    - Optimized performance: FastImage caching, FlatList/SectionList virtualization, memory leak fixes, and Hermes engine adoption — improved App Store rating from 3.2 to 4.5 stars
    - Integrated analytics (Mixpanel, Firebase Anal
Education verified_user 0% verified
  • M
    React Native
    Meta, on Coursera
    Aug 2023
  • F
    Associate’s Degree, Computer Science
    Finance University, Moscow
    Sep 2016 - Jun 2020 (3 years 10 months)
  • F
    Associate's degree, Computer Science
    Finance University
    Sep 2016 - Jun 2020 (3 years 10 months)
Projects (professional or personal) verified_user 0% verified
  • B
    BankLink
    Feb 2026
    bank-link.app
    Founder & Solo Developer
    Designed and built a cross-platform fintech application that scans bank statements and transforms them into actionable financial insights, supporting multi-bank aggregation across different countries.
    Architected an offline-first, privacy-focused system with zero cloud dependency — all data processing happens on-device using local storage and on-device OCR, eliminating third-party data exposure.
    Built full stack: React Native mobile app (TypeScript, Reanimated, Three.js for 3D visualizations), Node.js/Express backend, and a marketing landing page.
    Implemented document scanning pipeline
  • H
    Habit quit
    Nov 2024 - Jan 2025 (3 months)
  • S
    Socios App (Chiliz)
    Aug 2023 - Dec 2023 (5 months)
    https://play.google.com/store/apps/details?id=com.socios
    Contributed as Senior React Native Developer to the Socios fan engagement platform with 2M+ registered users
  • T
    TianDe App
    Jun 2019 - May 2021 (2 years)
    https://apps.apple.com/en/app/ecodeviva-by-tiande/id1248325926
    Took part in React Native development for a 100K+ installs e-commerce mobile app