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I'm Justin O’Hara, a senior mobile developer focused on building scalable iOS and Android apps. I specialize in React Native and native modules, with strong backend integration to deliver reliable, high-performance experiences for healthcare, fintech, and food delivery. I thrive in cross-functional teams, emphasize clean architecture, real-time data handling, and offline-first strategies. I mentor junior developers, advocate for robust testing, performance optimization, and a smooth, intuitive user experience across platforms.…I'm Justin O’Hara, a senior mobile developer focused on building scalable iOS and Android apps. I specialize in React Native and native modules, with strong backend integration to deliver reliable, high-performance experiences for healthcare, fintech, and food delivery. I thrive in cross-functional teams, emphasize clean architecture, real-time data handling, and offline-first strategies. I mentor junior developers, advocate for robust testing, performance optimization, and a smooth, intuitive user experience across platforms.

Justin O’Hara

App Developer, Web Developer, Full Stack Developer, +2

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I'm Justin O’Hara, a senior mobile developer focused on building scalable iOS and Android apps. I specialize in React Native and native modules, with strong backend integration to deliver reliable, high-performance experiences for healthcare, fintech, and food delivery. I thrive in cross-functional teams, emphasize clean architecture, real-time data handling, and offline-first strategies. I mentor junior developers, advocate for robust testing, performance optimization, and a smooth, intuitive user experience across platforms.…I'm Justin O’Hara, a senior mobile developer focused on building scalable iOS and Android apps. I specialize in React Native and native modules, with strong backend integration to deliver reliable, high-performance experiences for healthcare, fintech, and food delivery. I thrive in cross-functional teams, emphasize clean architecture, real-time data handling, and offline-first strategies. I mentor junior developers, advocate for robust testing, performance optimization, and a smooth, intuitive user experience across platforms.

Available to hire

I’m Justin O’Hara, a senior mobile developer focused on building scalable iOS and Android apps. I specialize in React Native and native modules, with strong backend integration to deliver reliable, high-performance experiences for healthcare, fintech, and food delivery.

I thrive in cross-functional teams, emphasize clean architecture, real-time data handling, and offline-first strategies. I mentor junior developers, advocate for robust testing, performance optimization, and a smooth, intuitive user experience across platforms.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Intermediate

Work Experience

Senior Mobile Developer at CookUnity

October 1, 2025 - October 1, 2025

Led migration of CookUnity's food delivery app to React Native Expo with EAS, implemented shipping integrations via EasyShip API, and introduced real-time delivery tracking using WebHooks, FCM, and Firestore. Optimized Google Maps usage, enhanced location tracking, and improved map rendering performance. Implemented dynamic product catalogs with advanced filtering, migrated QR code recognition to native modules for performance, and added deep linking for notification-driven navigation. Implemented offline-first patterns with AsyncStorage/SQLite, upgraded to RN 0.76 with Fabric and Hermes, and integrated TurboModules for faster startup. Added crypto-payment option, AWS cloud services, AI-driven search enhancements, secure OAuth 2.0/JWT, and GraphQL integration. Conducted extensive testing with Jest and RN Testing Library; optimized debugging with Flipper and Sentry. Set up CI/CD pipelines with Bitrise and GitHub Actions.

Senior Software Developer at Boston Consulting Group

July 1, 2023 - July 1, 2023

Migrated VSee’s native iOS/Android apps into a unified React Native 0.64 codebase, consolidating shared UI logic while maintaining HIPAA compliance across Messenger, Clinic, and Telehealth platforms. Implemented WebRTC with a custom signaling API to replace Zoom SDK for secure, reliable video sessions; added BLE connectivity to auto-sync readings from medical devices; extended device streaming with native bridges for ultrasound/otoscope feeds; built a dynamic waiting room and in-visit chat using Socket.IO; added PiP and screen sharing; optimized low-bandwidth scenarios; adopted Zustand for state management and implemented e-signature workflows; integrated secure in-app payments via Stripe; improved background reconnection, testing, and CI/CD with Fastlane and AWS Amplify.

Mobile Developer at FinTron

February 1, 2020 - February 1, 2020

Built FinTron mobile app with React Native, Redux, and TypeScript; connected RESTful APIs, WebSockets, and Firebase for real-time balances and activity synchronization. Implemented secure authentication using OAuth 2.0, JWT, and biometrics; developed dynamic transaction and budgeting screens with D3.js and Recharts; integrated peer transfers, stock trading via Plaid/Stripe/Alpaca; improved reliability with Redux Thunk, AsyncStorage, and Sentry; added offline support with local sync and data persistence.

Software Developer at Tango

March 1, 2017 - March 1, 2017

Built a full-stack construction management platform with MongoDB, Express, React, Node.js, and related web tech; created a client portal for approvals and document sharing; designed an inventory module with live records and Redux-managed state; developed mobile modules in native Android (Java) and iOS (Swift) to extend web functionality; integrated push notifications, file uploads, and on-site data capture to ensure real-time synchronization with the backend.