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Need someone who can build, stabilize and scale your Android product? You just found him 🤝 📊 12+ years in mobile delivery 📊 20+ Android-focused projects 📊 10+ years supporting regulated and business-critical products 📊 Experience with compliance-ready apps, secure payments, backend-heavy systems and Software Development I help companies create secure, maintainable, high-performance apps for Healthcare, FinTech and consumer products. Core Expertise 🔹 Native Android engineering with modern architecture and Software Design 🔹 Kotlin-first development with maintainability in mind 🔹 Legacy modernization from Java to Kotlin 🔹 Secure integrations, performance tuning, release stability 🔹 Product delivery for Healthcare, FinTech, consumer platforms and Mobile App Development I’m an android developer focused on products where reliability and clean architecture matter. As a kotlin developer, I build scalable solutions with android kotlin best practices, Jetpack tooling and AOSP awareness. Clients come to me for android developer kotlin expertise when they need stability, lower technical debt and growth. I work as an android app developer on products that need more than interface implementation. I support teams with android app development for secure solutions where every android app stays maintainable after launch. My background: improving an android application used by thousands of users, integrating backend systems, payment flows, and healthcare-grade data handling. That is why companies hire me as an android mobile developer ( android mobile app developer ) when they need delivery. What I Do Best ✅ Android development using Kotlin and Java ✅ Architecture design with MVVM, Clean Architecture, modularization ✅ Backend communication, authentication and payment integrations ✅ Performance optimization, debugging, maintenance and release support ✅ Application Improvement for live mobile products ✅ Solo delivery or collaboration inside a larger team My strongest specialization is android developer kotlin work. I often join teams that need android developer kotlin java skills to modernize legacy code, migrate modules, and improve release quality without a full rewrite. That work benefits from practical experience as a java developer and from thinking like an android kotlin developer who can handle new features and stabilization. Relevant Experience Highlights 🔸 Healthcare mobile applications with compliance-aware architecture 🔸 Performance optimization and crash-rate reduction 🔸 Secure data handling and app stability improvements 🔸 Secure apps with payment integration and transaction-safe flows 🔸 Backend integrations with PHP, Python, JavaScript, and REST APIs 🔸 Collaboration with iOS, backend, QA, and web teams 🔸 Ability to scale from one engineer to a delivery team I also have experience with android ble and android bluetooth features for pairing flows and reliable data exchange. Whether I contribute to an android mobile app or support an existing codebase as a mobile developer, I focus on release readiness. Tech Stack 🔸 Android kotlin with Jetpack, Compose, Android SDK, AOSP 🔸 Java, Firebase, secure cloud services, CI/CD 🔸 REST APIs, secure auth, payment gateways 🔸 Node.js, JavaScript, C#, SQL for backend alignment 🔸 Git, Android Studio, release workflows, crash analysis 🔸 MVVM, Clean Architecture, modular apps, scalability-first mindset My work is rooted in native Android, but I also understand broader product ecosystems. I collaborate effectively as an ios developer ( ios app developer ) when cross-platform alignment matters, including iOS Development discussions with teams using Swift. I have worked alongside teams using react native and reviewed delivery implications where flutter developer was involved, though I do not present those as my core specialization. That exposure helps me operate as an android developer and product-minded mobile app developer within cross-functional teams. Team & Product Collaboration 🔹 Coordination with a rest api developer 🔹 Alignment with web application development 🔹 Communication with a web developer or front end developer 🔹 Familiarity with database builder, django, and python automation Support I Can Provide ✔️ Build a mobile app from scratch ✔️ Join an existing product as an app developer android ✔️ Refactor legacy code and modernize architecture ✔️ fix android application bugs and improve release readiness I do not position myself as a wordpress, magento, game developer or unreal engine specialist and I do not use unrelated positioning such as android developer india. Even when someone types android develoer, they usually need a senior specialist who can take ownership. I built mobile applications for autism-related projects with intuitive user experience. 📬 If you need an android developer who can improve an existing product, build a reliable solution from scratch or support growth with kotlin developer depth, send me a message.

🟢 AVAILABLE TODAY, JUNE 6 ⚡ Message me "AUDIT" - get a free 30-min technical review of your app idea, architecture, or existing codebase. No sales pitch. Just honest engineering feedback. I'm Siarhei - ex-CTO × 3 funded startups, CEO of Sparkler Soft. We build native iOS & Android products that ship, scale, and raise. 🔵 PROVEN RESULTS ◈ iHairium - AI Hair Diagnostics (live on App Store) Neural network · 100K+ training images · 95-98% accuracy $600K angel round + $5M seed valuation Revenue ×10 to ×1000 per month in early stages Google & Amazon grants · 1,000+ clinic partners onboarded ◈ Eco-Go - Electric Scooter Sharing Platform iOS + Android + Backend + IoT + Admin Panel AWS IoT Device Management · Swappable battery infrastructure Named "Best Startup of the Region" ◈ Optics Platform [White-label · Strict NDA] AI-assisted frame & lens selection via device camera Active in 60+ countries · 1,000+ fitting points worldwide 10+ years on market · Award-winning at international exhibitions ◈ Chibbis - Unified Food Delivery Service 600+ restaurants · 150+ cities across Russia iOS + Android + Web + Admin Panel + CMS One of the country's leading delivery platforms ◈ CoinForShop - Crypto Marketplace iOS + Android + Web (React) Non-custodial wallets · Smart contract payments BTC · ETH · BCH · LTC · XMR · TRX · 100% MVP delivered ◈ Azarium - NFT Real Estate Investment Platform Fractional property ownership via blockchain MAS-regulated · Live construction webcam in-app Min investment from $200 · Expected ROI 30–60% 🟠 WHAT WE BUILD → HealthTech & AI On-device ML · Camera diagnostics · Neural networks TensorFlow Lite · Core ML · OpenCV → FinTech & Crypto Wallets · KYC/AML · Stripe · Smart contracts · NFT → Mobility & IoT GPS · BLE · AWS IoT · Scooter & bike sharing Telematics · Real-time fleet management → Marketplace & Delivery Full-stack: app + backend + admin panel + CMS → API Integrations Stripe · Mapbox · Sumsub · Firebase · any third-party 🟡 TECH STACK Mobile: Swift · SwiftUI · Objective-C · Kotlin · Java Backend: Java Spring Boot · Node.js · NestJS · Golang Frontend: React · Next.js AI/ML: TensorFlow Lite · Core ML · OpenCV Cloud: AWS · GCP · Azure · Docker · Kubernetes · CI/CD Data: PostgreSQL · MongoDB · Redis · Elasticsearch Security: OAuth2 · OIDC · JWT · Keycloak · Biometrics · IAP 👉 Message "AUDIT" right now - 30 minutes to understand if we're the right fit. No obligation. No pitch. Just clarity.

✅ Expert-Vetted badge holder ✅ Upwork Top Rated Premium Mobile Application Developer ✅ 250+ Applications Developed ✅ 100 % Client Recommendation 🌟 Full-Stack Mobile App Developer | Android, iOS, Hybrid Apps Specialist With expertise across frontend, backend, mobile app development (Android & iOS), and marketing, I have successfully created and improved dozens of applications across diverse domains like entertainment, fitness, education, self-help, lifestyle, and commerce. My focus is on delivering seamless, user-friendly apps that meet your business goals. Key Skills and Roles: - Full-Stack Mobile App Developer - Hybrid App Developer (Flutter, React Native) - Swift & Kotlin Expert - Android & iOS Developer Frameworks and Technologies I Use: - Mobile Development: Kotlin, Java, Swift, Objective-C, Flutter, React Native - Backend Development: PHP, Laravel, Node.js - Native SDKs: Android & iOS Expertise Includes: - Android & iOS App Development using Kotlin, Java, and Swift - Integration of RESTful APIs, Payment Gateways, and Social SDKs - Augmented Reality (AR) features and Firebase solutions - Voice, Chat, and Virtual Bot Integrations - Map, Ads, and In-App Purchases Implementation - Progressive Web Apps (PWA) & Alexa Skill Kit (ASK) Design Third-Party API Support: - Google APIs (Map, Places, Plus) - Facebook, Twitter, Instagram, Pinterest APIs - Dropbox API Chat Support Solutions: - Firebase Group Chat - SendBird - Quickblox API & Web Service Integration: - JSON & XML-Based APIs - REST & SOAP-Based APIs Database Expertise: - Firestore, Firebase, Realm, MongoDB, DynamoDB Analytics & Bug-Tracking Solutions: - Crashlytics - Google Analytics - MixPanel Development Standards: - Clean, robust, and well-commented code with optimized naming conventions - Version control using GitHub & Bitbucket Why Choose Me? - Proven track record of delivering successful applications. - Deep technical expertise in mobile and web development. - Focus on client satisfaction through clear communication and timely delivery. - Confidentiality guaranteed for all projects under NDA. Feel free to reach out with your project details, ideas, or challenges. Let’s collaborate to bring your vision to life! 🚀 Thanks, and I look forward to working with you!

Are you tired of maintaining two separate codebases for Android and iOS? I help startups and businesses ship both platforms faster with a single, shared Kotlin codebase using Kotlin Multiplatform (KMP) and Compose Multiplatform (CMP). While most developers build for one platform, I specialize in the modern cross-platform stack that reduces your development cost by up to 50% — without sacrificing native performance or user experience. ──────────────────────────────────────────────────────────── 🔧 WHAT I BUILD ──────────────────────────────────────────────────────────── ✅ Cross-platform apps with shared UI using Compose Multiplatform (CMP) ✅ Shared business logic across Android & iOS with KMP ✅ Native Android apps with Jetpack Compose & Clean Architecture ✅ Migrating existing Android apps to Kotlin Multiplatform ✅ In-App Purchases, subscriptions & RevenueCat / Play Billing integration ✅ Push notifications (FCM / APNs), WebSockets & background processing ✅ REST API & WebSocket integration with Ktor ✅ Local caching with SQLDelight / Room KMP ✅ PDF generation, file handling, document upload & viewers ──────────────────────────────────────────────────────────── ⚙️ TECH STACK ──────────────────────────────────────────────────────────── Cross-Platform : Kotlin Multiplatform (KMP), Compose Multiplatform (CMP) Android : Jetpack Compose, MVVM, Clean Architecture, Coroutines, Flow iOS : SwiftUI interop, Xcode, CocoaPods / SPM integration Networking : Ktor, Retrofit, WebSockets, REST APIs Storage : SQLDelight, Room KMP, DataStore DI : Koin, Hilt CI/CD : GitHub Actions, Fastlane, App Store Connect, Play Console Other : Firebase, OneSignal, RevenueCat, Coil, Kotlin Serialization ──────────────────────────────────────────────────────────── 💼 REAL-WORLD EXPERIENCE ──────────────────────────────────────────────────────────── I've shipped production KMP apps including AI-powered tools that run identically on Android and iOS with shared networking, business logic, background task processing, PDF exports, and subscription flows. I understand both platforms deeply: Android lifecycle, iOS Info.plist entitlements, App Store review guidelines, and Google Play publishing. ──────────────────────────────────────────────────────────── ✅ WHY CLIENTS CHOOSE ME ──────────────────────────────────────────────────────────── → One developer. Both platforms. One codebase. → Senior-level experience — no hand-holding needed → Clear communication and on-time delivery → I write code you can maintain, not spaghetti you'll regret If you want a developer who truly understands Kotlin Multiplatform and Compose Multiplatform not just someone who Googled it — let's talk. Send me a message describing your project and I'll respond within a few hours.

🚀 𝐓𝐡𝐞 𝐀𝐩𝐩 𝐒𝐭𝐨𝐫𝐞 𝐢𝐬 𝐜𝐫𝐨𝐰𝐝𝐞𝐝, 𝐚𝐧𝐝 𝐚𝐯𝐞𝐫𝐚𝐠𝐞 𝐝𝐞𝐬𝐢𝐠𝐧 𝐣𝐮𝐬𝐭 𝐝𝐨𝐞𝐬𝐧’𝐭 𝐜𝐮𝐭 𝐢𝐭 𝐚𝐧𝐲𝐦𝐨𝐫𝐞. Whether it’s a mobile app, a macOS desktop tool, or a UI that converts users demand performance, beauty, and seamless experience. That’s where I come in. I'm a 𝐌𝐨𝐛𝐢𝐥𝐞 & 𝐦𝐚𝐜𝐎𝐒 𝐀𝐩𝐩 𝐃𝐞𝐯𝐞𝐥𝐨𝐩𝐞𝐫 + 𝐔𝐈/𝐔𝐗 𝐃𝐞𝐬𝐢𝐠𝐧𝐞𝐫 with a proven record of building high-performance apps and clean, conversion-driven designs. I specialize in delivering Swift-powered solutions that combine sleek front-ends with rock-solid back-end logic. 🔧 𝐖𝐡𝐚𝐭 𝐈 𝐎𝐟𝐟𝐞𝐫: ✔ iOS Development (Swift, SwiftUI, Combine, CoreData) ✔ macOS Desktop App Development using native frameworks & APIs ✔ MVVM Architecture for scalable, clean codebases ✔ Firebase Integration (Realtime DB, Auth, Cloud Messaging, Firestore) ✔ Custom PDF Workflows with PDFKit ✔ Smooth Lottie Animations for next-level UI ✔ API Integration + JSON Serialization with precision ✔ UI/UX Design in Figma – From wireframe to final screen ✔ Responsive Design for all screen sizes (Mobile + Desktop) ✔ Landing Pages & Web UI that convert visitors into users 💡 𝐖𝐡𝐲 𝐂𝐥𝐢𝐞𝐧𝐭𝐬 𝐇𝐢𝐫𝐞 𝐌𝐞: ✔ 6+ years of experience across mobile, desktop & UI design ✔ Cross-disciplinary skills I don’t just code, I design with purpose ✔ Clean, modular code that’s easy to scale and maintain ✔ Great communication, deadline-oriented, and focused on ROI ✔ Solutions built around real user behavior not just trends 🏆 𝐑𝐞𝐜𝐞𝐧𝐭 𝐏𝐫𝐨𝐣𝐞𝐜𝐭𝐬: 🔗 𝐏𝐨𝐫𝐭𝐟𝐨𝐥𝐢𝐨 𝟏 – 𝐒𝐰𝐢𝐟𝐭𝐔𝐈 + 𝐏𝐃𝐅𝐊𝐢𝐭 𝐀𝐩𝐩 𝐰𝐢𝐭𝐡 𝐅𝐢𝐫𝐞𝐛𝐚𝐬𝐞 𝐒𝐲𝐧𝐜 Developed a cross-platform app (iOS + macOS) using SwiftUI and PDFKit, integrated with Firebase for real-time data sync and custom PDF export workflows. 🔗 𝐏𝐨𝐫𝐭𝐟𝐨𝐥𝐢𝐨 𝟐 – 𝐦𝐚𝐜𝐎𝐒 𝐃𝐞𝐬𝐤𝐭𝐨𝐩 𝐀𝐩𝐩 𝐰𝐢𝐭𝐡 𝐂𝐨𝐫𝐞𝐃𝐚𝐭𝐚 + 𝐂𝐨𝐦𝐛𝐢𝐧𝐞 Delivered a clean, MVVM-structured desktop app using CoreData and Combine for smooth UI updates and persistent storage. 🔗 𝐏𝐨𝐫𝐭𝐟𝐨𝐥𝐢𝐨 𝟑 – 𝐀𝐏𝐈-𝐏𝐨𝐰𝐞𝐫𝐞𝐝 𝐀𝐩𝐩 𝐰𝐢𝐭𝐡 𝐋𝐨𝐭𝐭𝐢𝐞 𝐀𝐧𝐢𝐦𝐚𝐭𝐢𝐨𝐧𝐬 Built a visually rich app featuring Lottie animations and seamless third-party API integration for enhanced interactivity. 🔗 𝐏𝐨𝐫𝐭𝐟𝐨𝐥𝐢𝐨 𝟒 – 𝐑𝐞𝐬𝐩𝐨𝐧𝐬𝐢𝐯𝐞 𝐒𝐡𝐨𝐩𝐩𝐢𝐧𝐠 𝐀𝐩𝐩 𝐔𝐈 𝐢𝐧 𝐅𝐢𝐠𝐦𝐚 Designed a mobile shopping app UI in Figma with responsive layouts, optimized for usability across iPhone and iPad screens. You can explore these live projects in my portfolio for real examples of my code, design, and delivery standards. 👥 𝐖𝐡𝐨 𝐈 𝐖𝐨𝐫𝐤 𝐖𝐢𝐭𝐡: Startups & Entrepreneurs launching new mobile or macOS apps Agencies who need reliable developers/designers for client work Businesses looking to redesign or optimize mobile/Desktop UI/UX Tech teams who need clean architecture, API handling, and modern Swift coding 🎯 𝐓𝐞𝐜𝐡 𝐒𝐭𝐚𝐜𝐤 & 𝐓𝐨𝐨𝐥𝐬: Languages/Frameworks: Swift, SwiftUI, Combine, Firebase, MVVM, CoreData Design: Figma, Lottie, Responsive Design Tools: PDFKit, REST APIs, JSON serialization, Git You’ve got a product that deserves to perform and look outstanding let’s make sure your users love every tap, swipe, and click. Click “Invite” and let’s build something that scales, converts, and stands out.

🏆 TOP RATED | Top 10% Freelancer on Upwork I build high-quality, production-ready mobile apps for startups, entrepreneurs, and established businesses. From idea → design → development → backend → payments → App Store & Google Play submission — I handle the full mobile lifecycle. I specialize in mobile app development, including custom iOS apps, Android apps, and Flutter cross-platform apps. If you’re looking to build or scale a full mobile product, I can take it from concept to a store-ready release with clean architecture and fast iteration. With 100% Job Success, Top Rated status, and experience delivering complete apps from scratch, I focus on reliability, clear communication, and real business results. What I specialize in • 📱 Flutter cross-platform apps (clean UI, scalable architecture, localization, animations) • 🤖 Android Native (Kotlin · Jetpack Compose) • 🍎 iOS Native (Swift · SwiftUI) • ⚙️ Backend integrations: Node.js, FastAPI, Postgres, AWS RDS, Firebase • 💳 Payments & monetization: Stripe (Subscriptions, Connect platforms, one-time payments), in-app purchases • 🔐 Authentication (Google, Apple, email/password, OTP) • 📦 Push notifications, deep links, scheduling, background tasks • 🚀 App publishing (TestFlight, Google Play, certificates, provisioning) What clients appreciate • Fast and clear communication • End-to-end delivery (you don’t need multiple developers) • Pixel-perfect UI implementation • Strong debugging skills — I fix what others cannot • Reliable, long-term collaboration • Clean, maintainable code Availability • Available daily • Time zone: EST (US Eastern Time) • Quick response and consistent updates 💬 Ready to get started? Let’s talk.