Hire the Best React Native Developers
in Vietnam

My profile caught your eye because you need a React Native developer. Not native iOS, not Android, not Flutter. You have probably already done the math. One codebase instead of two. One team, not separate Swift and Kotlin hires. A product that ships to both stores at once. Half the cost, twice the speed. You are right. For most apps, and for almost every crypto app, that is the correct call. Native is the heavyweight option. You write the app twice, once in Swift for iOS and once in Kotlin for Android. Two codebases, two skill sets, two sets of bugs. You get the best raw speed and the earliest access to new OS features. You also pay for all of it, in money and in time. Most apps never touch the ceiling native buys you. Flutter gives you one codebase, written in Dart. It draws every pixel with its own engine, so the screens look sharp and animate well. The trouble starts at the edges. Crypto and Web3 live in JavaScript. Wallet libraries, chain SDKs, WalletConnect, all built for the web first. Flutter cannot call them directly. You write, test, and maintain extra bridge code for features a wallet needs on day one. React Native gives you one codebase too, written in JavaScript and TypeScript. The difference is what it can reach. It runs the same libraries your web dApp already uses. The same ethers and viem for contracts. The same WalletConnect for signing. No bridge, no translation layer, no waiting. React Native shines wherever the logic is shared with the web. Most of all in a crypto app, where that logic is the product. Leading wallets like Rainbow and Coinbase Wallet run on React Native for this exact reason. That reach is why I went React Native only. I spent years building crypto wallets and Web3 apps. The work kept pulling toward the same JavaScript tools. So I stopped splitting my focus. These days clients come to me for one thing. Wallets people can trust with their own keys. Self-custody, no seed phrase to lose, every transaction signed on the device. React Native is where that gets built, and it is what I build. I also build other mobile apps than crypto. Some clients come to me for everyday consumer apps too. Social, fitness, lifestyle. Building those apps taught me one word. Monetize. So I built every piece around of it. RevenueCat for selling in-app purchases and subscriptions. Stripe for card payments. Firebase for push notifications that bring users back. I built nearby search with react-native-maps for Wizapp, a People Nearby social app. Crypto apps rarely need any of this. They earn on-chain, through tokens and trading fees. Consumer apps live on it. A few of the apps I have shipped: - Dextoro: a Solana memecoin trading app with a self-custody wallet, no seed phrases, and gas-free one-tap trades. 4.7 stars from 75 App Store reviews. - Kelp: a self-custody Web3 wallet with a token-reward referral engine, live on both stores. - Synesis One: a Solana Train2Earn dApp where users earn SNS tokens for AI data-labeling tasks, each one wallet-signed on-chain. - Web3app Portfolio Tracker: one view for crypto, stocks, NFTs, and tokenized assets, with live prices and encrypted storage. Every one runs on a single React Native codebase across iOS and Android. Every one is on the App Store and Google Play, signed, reviewed, and live. The stack I reach for: React Native and Expo, TypeScript, Redux for state, Reanimated for motion, WalletConnect and chain SDKs for Web3. When a feature needs native speed, I write the bridge myself. I did exactly that on a 1,033-hour bridge project rated 5.0. The record backs the work. Top Rated Plus, 100% Job Success, 18,000 hours, 80 clients. Certified as an Anthropic Claude Architect, an Atlassian Expert. One client put it better than I can: 🗣️ "I have been working with Phung for just over a month and I have to say he is one of the most professional mobile developers I have worked with. He is very knowledgeable and definitely has the experience. He picked up two projects for additional updates, bug fixes, and prioritised both incredibly well. Will continue to work with him for as long as I have work with React Native." Tell me the app you want to build. A wallet, a trading app, a Web3 product that has to feel fast and get paid. I will tell you the shortest path to a build that is live on both stores. 🕛 I work in UTC+7 and cover ANZ, Asia, and US hours.

I build, maintain, and ship production mobile applications with React Native, native iOS, and native Android. My main strength is going beyond the JavaScript layer. With 8+ ʏᴇᴀʀꜱ ᴏꜰ ʀᴇᴀᴄᴛ ɴᴀᴛɪᴠᴇ ᴇxᴘᴇʀɪᴇɴᴄᴇ and 9+ ʏᴇᴀʀꜱ ɴᴀᴛɪᴠᴇ ᴍᴏʙɪʟᴇ ᴀᴘᴘ ᴅᴇᴠᴇʟᴏᴘᴍᴇɴᴛ, I can work directly with Kotlin/Java, Swift/native iOS, native modules, SDK integrations, bridges, platform-specific bugs, performance issues, and production problems. I also use AI-assisted engineering workflows daily with tools such as Cursor, Codex, Claude, ChatGPT, GitHub Copilot, and other coding agents. This allows me to quickly understand large or unfamiliar codebases, implement features, debug issues, refactor AI-generated code, and ship faster while keeping the code maintainable. 🚀 𝐖𝐇𝐀𝐓 𝐈 𝐂𝐀𝐍 𝐇𝐄𝐋𝐏 𝐘𝐎𝐔 𝐖𝐈𝐓𝐇 ➡️ Build React Native applications from scratch ➡️ Take over and maintain existing React Native codebases ➡️ React Native ↔ native iOS/Android integration ➡️ Native modules and third-party SDK integration ➡️ Kotlin/Java Android development ➡️ Swift/iOS development ➡️ Production crash and performance debugging ➡️ React Native modernization and migration ➡️ AI-powered mobile applications and LLM integrations ➡️ Review, debug, refactor and productionize AI-generated code ➡️ App Store / Google Play release and CI/CD ➡️ Backend/API integration and real-time features 📱 𝐑𝐄𝐀𝐂𝐓 𝐍𝐀𝐓𝐈𝐕𝐄 💼 8+ ʏᴇᴀʀꜱ ᴇxᴘᴇʀɪᴇɴᴄᴇ React Native, TypeScript, Redux, Zustand, MobX, Realm, SQLite, MMKV, WatermelonDB, REST APIs, WebSockets, authentication, background tasks, native modules, Fastlane, Bitrise and AWS. 🍎 𝐢𝐎𝐒 & 🤖 𝐀𝐧𝐝𝐫𝐨𝐢𝐝
(𝘎𝘰𝘰𝘨𝘭𝘦 𝘤𝘦𝘳𝘵𝘪𝘧𝘪𝘤𝘢𝘵𝘦 📜) 7+ ʏᴇᴀʀꜱ ᴏꜰ ᴀɴᴅʀᴏɪᴅ ᴅᴇᴠᴇʟᴏᴘᴍᴇɴᴛ (Java/Kotlin), 3+ ʏᴇᴀʀꜱ ᴏꜰ ɪᴏꜱ ᴅᴇᴠᴇʟᴏᴘᴍᴇɴᴛ (Objective C/Swift) with experience working close to the native platform. Android: Kotlin, Java, Coroutines, RxJava, Retrofit, Dagger/Hilt, Room, SQLite, Realm, Espresso, Robolectric, Fastlane and Bitrise. iOS: Swift/native integration, React Native bridges, native modules, SDK integration, authentication, networking and platform-specific debugging. This native experience is especially useful when a React Native project requires functionality that cannot be solved cleanly from JavaScript alone. 🤖 𝐀𝐈-𝐀𝐬𝐬𝐢𝐬𝐭𝐞𝐝 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐢𝐧𝐠 I use AI development tools as part of my daily engineering workflow, including Cursor, Codex, Claude, ChatGPT, GitHub Copilot and other agentic coding tools. I can: * Quickly understand and navigate large existing codebases * Debug and refactor AI-generated / AI-assisted code * Improve architecture and maintainability of "vibe-coded" applications * Use AI agents to accelerate implementation, testing and debugging * Integrate OpenAI, Anthropic Claude, Gemini, Grok, DeepSeek and custom LLM backends * Build AI features such as chat assistants, document analysis, summarization, content generation, recommendations, voice, image generation and personalized insights * Work with both cloud-based AI APIs and on-device AI where appropriate
 🦋 𝐅𝐋𝐔𝐓𝐓𝐄𝐑 💼 5+ ʏᴇᴀʀꜱ ᴇxᴘᴇʀɪᴇɴᴄᴇ Flutter, Dart, Provider, BLoC, MobX, GetX, SQLite, SharedPreferences, Dio, Flutter testing and CI/CD. 🌐 𝐀𝐝𝐝𝐢𝐭𝐢𝐨𝐧𝐚𝐥 𝐞𝐱𝐩𝐞𝐫𝐢𝐞𝐧𝐜𝐞 Node.js, Express, MongoDB, REST APIs, real-time applications, e-commerce, crypto/Web3, health/fitness, video streaming, social applications and other production systems. 𝐖𝐇𝐘 𝐂𝐋𝐈𝐄𝐍𝐓𝐒 𝐖𝐎𝐑𝐊 𝐖𝐈𝐓𝐇 𝐌𝐄 I am comfortable joining a project at any stage — from building a new application to taking over an existing codebase that needs debugging, modernization, native integration or production support. If your project involves React Native + native iOS/Android + SDK integration, or you need an engineer who can use modern AI tools without relying on AI blindly, I can help.

Over 7 years of experience building mobile apps for iOS and Android, from first concept to a live listing on the App Store and Google Play. I work fluently in both native languages (Swift, SwiftUI, Java, Kotlin, Jetpack Compose) and cross-platform frameworks (React Native, Flutter), so I can recommend the right approach for your product instead of forcing one stack onto every problem. That broad experience helps clients make the call that fits their goals. Should you use React Native or Flutter to ship faster and lower cost? Should you go native for maximum performance and the latest platform features? Those are exactly the trade-offs I help you weigh before a line of code is written. I don't just build to a spec, I help define it. I can join at any stage of the app lifecycle: clarifying requirements, UX and architecture decisions, development, testing, release, and post-launch iteration. I've taken apps through the full App Store and Google Play submission and review process many times and can guide you through it smoothly. WHAT I BRING + Platforms: iOS (iPhone, iPad), Android (phone, tablet) + Native: Swift, SwiftUI, UIKit, Objective-C basics, Java, Kotlin, Jetpack Compose + Cross-platform: React Native, Flutter (Dart), Expo + Languages: Swift, Kotlin, Java, JavaScript, TypeScript, Dart + Backend & data: RESTful and GraphQL APIs, Firebase, real-time sync, offline-first data, local storage (SQLite, Realm, Core Data) + Common features: Google/Apple Maps, geolocation, push notifications (FCM, APNs), in-app purchases, subscriptions, Stripe and payment integrations, social login, camera and media + Architecture: MVVM, MVC, Clean Architecture, state management (Redux, Provider, Bloc) + Quality: unit and UI testing, high code coverage, debugging and crash reporting (Crashlytics, Sentry) + Performance: optimizing battery, smoothness (60fps UI), memory, and network usage + Release & DevOps: App Store and Google Play submission, TestFlight, Fastlane, CI/CD for mobile (GitHub Actions, Bitrise) + Tools: Xcode, Android Studio, VS Code, Git Whether you need a new app built from scratch, an existing one improved and stabilized, or advice on the best technical path forward, I'd be glad to help you ship something users actually enjoy.

I build production ready mobile applications using React Native and Flutter for businesses that need reliable, scalable, and high performance products. My expertise is focused on Fintech, Logistics, and B2B SaaS applications, where stability, real time communication, secure data handling, and long term maintainability matter far more than simply shipping features. I enjoy working on products that people depend on every day. Whether it is processing payments, tracking deliveries, managing business operations, or connecting teams in real time, I focus on building applications that continue performing reliably as users and business requirements grow. I have worked on mobile applications that involve much more than UI implementation. My experience includes payment processing, real time synchronization, background services, offline functionality, push notifications, location tracking, API integration, authentication, and performance optimization under real world conditions. I mainly work with startups and growing businesses from the United States, United Kingdom, Canada, Australia, and Germany, and I can easily align with your timezone to keep communication fast and development moving efficiently. 💰 Fintech Applications Financial applications demand accuracy, security, and consistency. Small technical issues can quickly become business problems. I help clients solve challenges such as: 🔹 Preventing duplicate transactions during unstable network conditions 🔹 Building reliable wallet and balance synchronization 🔹 Integrating Stripe and secure payment gateways 🔹 Implementing secure authentication and role based permissions 🔹 Creating financial dashboards with real time updates 🔹 Improving API reliability for payment processing The result is stable financial applications that users can trust while remaining easy to maintain as the platform grows. 🚚 Logistics and Mobility Applications Logistics platforms require constant synchronization between users, drivers, dispatchers, and backend systems. I build applications capable of handling real operational environments by solving challenges including: 🔹 Live GPS tracking with optimized battery consumption 🔹 Real time driver and delivery status synchronization 🔹 Offline functionality with automatic background synchronization 🔹 Route visualization using Google Maps SDK 🔹 Background location updates without affecting performance 🔹 Push notifications for deliveries and operational events The result is dependable logistics applications that continue working even under unstable network conditions. 🏢 B2B SaaS and Business Applications Many business applications become difficult to maintain as teams and workflows grow. I build scalable mobile applications that improve business operations while remaining simple for end users. Typical challenges I solve include: 🔹 Multi role authentication and permission systems 🔹 Real time synchronization across multiple users 🔹 Offline data collection with automatic syncing 🔹 CRM, ERP, payment platform, and third party API integration 🔹 Dashboard optimization for large business datasets 🔹 Secure cloud based architecture for business applications The result is mobile platforms that help businesses improve productivity without sacrificing reliability or performance. ⚙️ Technical Skills • React Native • Flutter • JavaScript • TypeScript • Node.js • Express • FastAPI • Firebase Authentication • Firebase Firestore • Firebase Cloud Messaging • Supabase • PostgreSQL • Supabase Edge Functions • Stripe • Google Maps SDK • REST APIs • GraphQL • WebSockets • Redux • Zustand • Git • GitHub Actions • CI/CD • App Store Deployment • Google Play Store Deployment 🧠 My Development Approach ✔ Designing scalable application architecture before development ✔ Building reliable API integration with proper error handling ✔ Planning offline functionality from the beginning ✔ Optimizing application performance throughout development ✔ Writing clean, maintainable, and reusable code ✔ Testing edge cases before release ✔ Delivering applications ready for production deployment 🌍 Clients I Work With I primarily work with startups, SaaS companies, and growing businesses building long term digital products. Industries I commonly work with include: • Fintech • Logistics • Fleet Management • Transportation • B2B SaaS • Business Operations • Field Service Management • Delivery Platforms • Internal Business Tools ⏰ Timezone I can align with your timezone to ensure efficient communication, quick feedback cycles, and smooth collaboration throughout the project. If you're building a mobile product and need someone who focuses on reliability, scalability, and long term success instead of simply delivering screens, feel free to click the Message button. I'd be happy to discuss your project and explore how we can build a mobile application that is ready for real users from day one.

A client in the US shipped a Bluetooth device halfway around the world, all the way to me here in Vietnam. Then he waited three weeks for it to arrive. He could have hired someone much closer to home. He chose to wait for me instead. That story tells you what I actually do. Anyone can build a mobile app. The hard part is making the app work with a real physical device, and keeping it connected when you switch to another app, the signal gets weak, or the battery runs low. That's where most projects quietly fail. It's also why my client didn't want the nearby option. He wanted someone who would get the device right, and built the app right. Over 17,000 hours on Upwork and 70+ clients, I've built apps for all kinds of devices: a heart monitor used in healthcare, car alarm and remote-start systems, a tap-to-pay card reader, a skydiving altimeter, Bluetooth printers, and smart scales. I even keep a shelf of the small electronic boards these devices run on. But the device is only half the job. To deliver the whole product, I work across every major mobile toolset: Flutter, iOS, Android, and React Native. I pick the right one for your project, or match the app you already have. So one person handles the app, the connection to your device, and getting it approved on the App Store and Google Play. Not three separate hires. Recently, I'm now Anthropic-certified in building with Claude, and it would benefit you if we go together. Claude handles the repetitive coding work, so you need a smaller team (one senior developer now covers what used to take several) and launch sooner & monetize quicker. One past client said it better than I can: 🗣️ "Hau demonstrated excellent knowledge and skill in completing the project and produced high quality outcomes. The project involved a complicated architecture with both cloud and hardware connections which Hau was able to handle well." Google Certified Android Developer · Anthropic Claude Certified · Upwork Top Rated Plus (top 3% of freelancers, 100% Job Success) If you have a device that needs an app, or an app that needs to go live, send me a message and let's talk. 🕛 I'm in ICT (UTC+7️⃣), but can work in any time zone.

𝐖𝐞 𝐨𝐟𝐟𝐞𝐫 𝐅𝐑𝐄𝐄 𝐭𝐞𝐜𝐡𝐧𝐢𝐜𝐚𝐥 𝐜𝐨𝐧𝐬𝐮𝐥𝐭𝐚𝐭𝐢𝐨𝐧 𝐚𝐧𝐝 𝐚 𝐅𝐑𝐄𝐄 𝐪𝐮𝐢𝐜𝐤 𝐫𝐞𝐯𝐢𝐞𝐰 𝐨𝐟 𝐲𝐨𝐮𝐫 𝐩𝐫𝐨𝐣𝐞𝐜𝐭, 𝐚𝐧𝐝 𝐮𝐬𝐮𝐚𝐥𝐥𝐲 𝐫𝐞𝐬𝐩𝐨𝐧𝐝 𝐰𝐢𝐭𝐡𝐢𝐧 𝐚 𝐟𝐞𝐰 𝐡𝐨𝐮𝐫𝐬. We are Teaser Software, an ITO company based in Hanoi, Vietnam. If you’re looking for a reliable team to take your project from idea → design → development → launch → maintenance, while leveraging AI to accelerate development and improve efficiency without compromising quality, you’re in the right place. Whether you already have a detailed specification or just an initial idea, we can help shape it into a clear roadmap with realistic timelines and costs. 𝐋𝐞𝐭’𝐬 𝐜𝐨𝐧𝐧𝐞𝐜𝐭. 𝐉𝐮𝐬𝐭 𝐬𝐞𝐧𝐝 𝐮𝐬 𝐚 𝐦𝐞𝐬𝐬𝐚𝐠𝐞 𝐚𝐧𝐲𝐭𝐢𝐦𝐞. 𝐖𝐞 𝐰𝐨𝐫𝐤 𝐰𝐢𝐭𝐡 𝐜𝐥𝐢𝐞𝐧𝐭𝐬 𝐚𝐜𝐫𝐨𝐬𝐬 𝐦𝐮𝐥𝐭𝐢𝐩𝐥𝐞 𝐭𝐢𝐦𝐞 𝐳𝐨𝐧𝐞𝐬, 𝐬𝐨 𝐨𝐮𝐫 𝐭𝐞𝐚𝐦 𝐢𝐬 𝐚𝐯𝐚𝐢𝐥𝐚𝐛𝐥𝐞 𝟐𝟒/𝟕, 𝐢𝐧𝐜𝐥𝐮𝐝𝐢𝐧𝐠 𝐰𝐞𝐞𝐤𝐞𝐧𝐝𝐬.