Hire the Best Android Developers
in Vietnam

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.

Build fullstack applications and AI-powered backends. 6+ years of shipping products, mostly with Kotlin (Android native) and Flutter, plus Python and Node.js on the backend. AWS Certified ML Engineer. Most of my work follows the same pattern: take an idea or spec, build the mobile app, wire up the backend, ship it. I've done this for crypto exchanges, e-commerce platforms (one had a 3D virtual try-on feature using Unity), social apps, and more recently AI products - a transcription app using self-hosted speech-to-text, an AI trading platform with LLM-driven backtesting, and an AI keyboard with on-device Gemma Nano. On the AI side, I work with LangChain, LangGraph, and RAG pipelines. I've built MCP servers that bridge LLMs with external APIs, deployed models with vLLM, and integrated Gemini into production apps. Not the "I watched a tutorial" kind of experience - I architect these systems end to end and put them in front of real users. Mobile is my core: - Kotlin + Jetpack Compose / Android Native, 6 years, 15+ shipped apps - Flutter + Dart cross-platform, 6 years - Clean Architecture, MVVM/MVI/BLoC - Blockchain wallets, NFT marketplaces (Ethereum, Polygon, BNB) Backend and AI: - Python (FastAPI, Django), Node.js, Go, Java - LangChain, LangGraph, LlamaIndex, RAG, vLLM, Gemini, Google ADK - MCP server development (Python, TypeScript, C#) - AWS (Lambda, SageMaker, ECS, API Gateway), Docker, CI/CD I've led teams up to 24 people and also shipped projects with 2-person teams. Both work fine - I adjust to what the project needs. If you need someone who can handle both the mobile frontend and the AI/backend plumbing, let's talk specifics.

Hello! My name is Hoang, and I'm a mobile app developer specializing in iOS and Android. 🎯Why you should hire me? I build production-ready with AI-powered tools like Claude / Codex, shipping faster without compromising code quality, architecture, or UX. ✅Best price with hight-quality work ✅Dedicated to the job process ✅Client satisfaction ✅Quick response ✅Alway available for new updates and maintaining/bug fixes. 🎯 Areas of Expertise: ◉ Native Mobile App Development: Swift, Objective-C, Kotlin, Java ◉ Cross-platform with React Native ◉ AI, Chatbot, SDK, Livestreaming, Social networking ◉ API Integration: AWS API Gateway, AWS Lambda, Rest API, JSON, XML, PHP, Node.js, Python ◉ Database: SQLite, MySQL, Parse, MongoDB, AWS DynmoDB, Firebase real-time DB ◉ Social Integration: Facebook, Twitter, Youtube, Instagram, Snapchat, Tinder ◉ Chat Video/Photo/Text: XMPP, Socket, Firebase, Twilio ◉ Payment Gateway: Paypal, Braintree, Stripe, Paywall, RevenueCat, AppHud ◉ In-app Features: In-App Purchase: Advertisement, Push Notifications, GCM, Google Analytics ◉ Version Control Tools: Github, Bitbucket, Gitlab ◉ Google Map, Apple Map kit, Geolocation, GPS, Location Tracking 💌 Please, feel free to send the invitation to your job post or message me. I'm always looking forward to engaging opportunities!

I am a Senior Mobile Application Developer with 10+ years of experience building, maintaining, and improving production-ready mobile applications across Android, iOS, Flutter, and React Native. My strongest expertise is Android development with Java and Kotlin , with extensive experience in mobile architecture, performance optimization, API integration, and complex application features. I also have strong hands-on experience with Flutter and cross-platform mobile development, allowing me to work effectively on both native and cross-platform projects. I specialize in helping businesses build new mobile applications, improve existing apps, fix complex issues, and integrate third-party services and APIs. What I can help you with 🔹 Native Mobile Development * Android — Java, Kotlin, Android SDK * iOS — Swift * Native UI, system components, background processing, notifications * Performance optimization and memory management 🔹 Cross-Platform Development * Flutter / Dart * React Native * Cross-platform architecture and reusable components * State management and scalable application structure 🔹 Mobile App Development & Maintenance * New feature development * Existing app improvements * Bug fixing and troubleshooting * Performance optimization * UI/UX implementation from Figma designs * App modernization and codebase refactoring * Android/iOS build and release support 🔹 Architecture & Code Quality * Clean Architecture * MVVM / MVP * SOLID principles * Kotlin Coroutines & Flow / StateFlow * Dependency Injection with Hilt * Room / SQLite * Firebase * REST APIs and JSON 🔹 API & Third-Party Integrations * RESTful APIs * Firebase Authentication / Firestore * Push Notifications * RevenueCat / In-App Purchases * Payment and subscription systems * Social login * Analytics and crash reporting * Third-party SDK integration * AI API integration * Enterprise backend integration I have experience working on mobile applications throughout the full development lifecycle — from architecture and implementation to debugging, optimization, testing, and production release. After several years as a hands-on developer, I became a Team Leader, where I was responsible for technical architecture, development standards, code reviews, technical decisions, and mentoring developers. Whether you need someone to build a mobile app from scratch or take over and improve an existing codebase, I can help analyze the current implementation, identify technical issues, and deliver a maintainable solution. Core Technologies: Android | Kotlin | Java | Android SDK | iOS | Swift | Flutter | Dart | React Native | Firebase | REST API | SQLite | Room | Clean Architecture | MVVM | MVP | Git

I’m a developer with experience in building Android App for small and medium sized businesses. Whether you’re trying to win work, list your services or even create a whole online store – I can help! I have 3 years of experience in developing Android apps using Kotlin and related technologies. And now I'm researching and developing apps using Flutter. I am an experienced person in publishing apps to the CH Play store.

I help game studios and indie developers build smooth gameplay mechanics, clean C# architecture, and custom game mods that scale easily. I enjoy building gameplay mechanics, AI behaviors, progression systems, and developer tools that make games more engaging, scalable, and easier to maintain. Main Services: • Unity Game Development • Gameplay Programming • Multiplayer Features • AI Behaviors • UI Systems • Performance Optimization • Game Mod Development (Python) • Sims 4 Modding • Gameplay Prototyping • Gameplay Tools Recent Projects: • Published Unity games for mobile and browser • Sims 4 gameplay mods with custom interactions and automation systems • Mobile game development and Google Play deployment • Gameplay prototypes and feature implementation for commercial clients I value clean architecture, clear communication, and reliable delivery. Whether you need gameplay programming, feature development, bug fixing, or custom game modding, I'd be happy to help bring your ideas to life.