Harsh S.Private profile: Upwork shows its earnings only to signed-in members, so we check it every few weeks, not daily. MRR here is a rough estimate (Upwork's six-month earnings ÷ months active). Last read Nov 5, 2026.

Senior Full Stack Mobile Engineer with 4+ years of experience building scalable, production-grade mobile applications using React Native, Expo, Android (Java), and .NET Core. I specialize in developing high-performance cross-platform applications for enterprise, government, workflow automation, and engagement-driven platforms with expertise in offline-first architecture, secure authentication systems, API integrations, and complex business workflows. I have hands-on experience building and deploying React Native + Expo applications for Android and iOS, including enterprise field-force apps, gamification platforms, donor engagement systems, and workflow-driven mobile solutions. My expertise includes offline sync engines, secure authentication, local storage optimization, deep linking, push notifications, and scalable API-driven mobile architectures. ✅ Helping Clients Build Scalable & Production-Ready Mobile Applications # Develop high-performance React Native applications for Android & iOS # Build offline-first mobile apps with reliable local storage and sync mechanisms # Design secure authentication systems with OTP, biometric login, and role-based access # Integrate REST APIs, backend services, payment systems, push notifications, and deep linking # Modernize and stabilize existing React Native or Android applications # Optimize app performance, reduce crashes, and improve scalability # Build enterprise workflow systems for field operations and business automation # Develop gamification features including rewards, streaks, engagement flows, and redemption systems # Deliver clean, modular, maintainable code aligned with long-term product growth 💻Types of Applications I Have Built: ✔ Enterprise & Government Field Team Applications Built offline-first mobile platforms for inspections, case management, scheduling, license handling, and field operations with automatic synchronization and secure authentication. ✔ Gamification & Engagement Platforms Developed apps with rewards systems, streak tracking, points management, redemption workflows, onboarding journeys, and push notification-driven engagement. ✔ Donor & Payment-Based Applications Implemented donation flows, secure payment integrations, checkout handling, transaction tracking, and deep-link based success/failure workflows. ✔ Workflow & Role-Based Applications Built applications with complex workflows for different user roles such as field staff, supervisors, and administrators with secure access management. ✔ Legacy Android App Modernization Enhanced and stabilized large Android Java codebases by improving performance, reducing crashes, optimizing RecyclerViews, and improving offline synchronization. ✔ Multi-language & Localization-Driven Apps Implemented dynamic language switching and localization systems for applications supporting multiple languages and regional users. ✅ Technical Expertise # Mobile Development: React Native, Android (Java), Cross-Platform App Development, React Native CLI, Mobile Architecture, Offline-First Systems # Backend Development: .NET Core, ASP.NET Core, REST APIs, Repository Pattern, API Integration # Databases & Local Storage: SQLite, PostgreSQL, SQL Server, MMKV, AsyncStorage, Firebase # Authentication & Security: Biometric Authentication, OTP Login, Secure Session Management, Role-Based Access Control (RBAC) # Advanced Mobile Features: Push Notifications, Deep Linking, Payment Integration, Offline Synchronization, Multi-language Support, Localization # Tools & Platforms: Git, Firebase Crashlytics, Play Console, Postman, Jira, Android Studio, Visual Studio I focus on building mobile applications that are not only visually polished but also scalable, secure, and reliable under real-world usage. Whether you need a new React Native application, backend integration, enterprise workflow solution, or long-term product development support, I can help deliver production-ready solutions built for scale and performance. 📌 Looking for a reliable React Native & Expo engineer who can build scalable, production-ready mobile applications? Let’s discuss your project requirements and build secure, high-performing Android & iOS apps together.