Hire the Best App Development Freelancers
in Vietnam

Are you looking for a seasoned expert in cross-platform mobile app development using Flutter? Look no further! 🔧 My Expertise: I excel in crafting high-quality cross-platform mobile apps using Flutter. I am well-versed in various design patterns, including BLoC, Provider, and GetX, and I'm fluent in programming languages such as Dart, Swift, Java, Objective-C, and JavaScript. Additionally, I have extensive experience with essential mobile frameworks like In-App Purchases, Maps, Camera, and Push Notifications. 📦 Third-Party Integration: I bring a wealth of experience in integrating third-party SDKs, making your app feature-rich and interactive. Some of the SDKs I've successfully integrated include Facebook, Stripe, Google Maps, AdMob, and more. 📊 Quality and Scalability: My commitment to quality is unwavering. I create apps that are not only responsive but also rigorously tested across a wide range of devices. I pride myself on delivering well-architected, well-documented, and easily maintainable projects, ensuring that your app can grow and adapt as your company does. ✅ My Skill Set: Languages: JavaScript, Dart, Java, Swift, Objective-C Platforms: Flutter, Android, iOS Familiar with SDKs & Tools: Firebase, Stripe, Mapbox, Google Maps, Facebook, Twitter, LinkedIn, and more Environments: Proficient in Windows and MacOS Version Control and Project Management: Bitbucket, Github, Jira, Trello, and others 💼 Let's Collaborate: If you're looking for a Flutter developer who can turn your app ideas into reality, I'm ready to discuss your project and bring it to life. My commitment to excellence and a track record of successful projects make me the ideal choice for your mobile app development needs. Let's build something great together!

For more than 11 years in mobile development, I have joined many projects, including ongoing and from scratch. With my skills, I can work as a Developer, Team Leader, and Project Manager. As a project manager, I communicate with clients directly, receive requirements, do business analysis, and estimate the time needed for the project. Setting up a mobile, backend, and frontend team to do the task. I decide to become a freelancer to join more and more projects, discover new technologies, and connect with clients worldwide. I am a good candidate for any client who wants the app to succeed. Some domains I have worked on: - Food and Beverage - eLearning - Health care system - Booking - Real estate - Fintech - ECommerce - ... My skill sets include: * Project management: I do Business Analyst, team management * Mobile native: Android, iOS (Swift) * Cross-platform: Flutter, React Native and Xamarin * Database: SQLite, SQL, Parse, Firebase Storage, Mongo DB Knowledge: * ReactJS. * WordPress * Angular * Java Spring Boot Project Management Software and Tools - Jira - Redmine - Trello

I am a professional embedded software engineer with more than 12 years of experience. My current areas of expertise are IoT Applications & Embedded Systems Design, including embedded hardware/software. 𝐌𝐘 𝐒𝐊𝐈𝐋𝐋𝐒: - Know about MCU: Nordic, Silicon Labs, AVR, PIC, ESP, TI CC32xx, ESP32, Qualcomm QCC51xx, etc. - Have experience in programming languages such as C/C++, C#, Java - Solid knowledge of standard interfaces such as I2C, SPI, UART, and CAN. - Have experience using debugging tools such as Segger Jlink, CAN bus analyzer, and Logic analyzer. - IoT devices with wireless connectivity such as LTE, CAT-M1, NB-IoT, LoRa/LoRaWAN, BLE, WIFI, NFC - Good experience in AWS Service, AWS IoT, AWS Shadow, and AWS Jobs. - Good experience in Battery Management Systems based on BQ products from TI. - Good experience with Audio Codec chips. - Experience with AI/ML on Edge Impulse with nRF Connect - True wireless earbuds, headsets and speakers, Bluetooth ® LE Audio standard from Qualcomm: QCC5141, QCC5171, QCC5181,... We have worked with wearable devices and medical devices: - ECG 1, 3, 12 leads with ADS1292, ADS1293, ADS1298 - EEG with ADS1299 - Body temperature with MAX302025, MAX30208 - PPG with MAX86178, MAX86178 - SPO2 with OB1203, MAX32664 sensor hub - Vital signal with AFE4950 - OTA firmware update via Bluetooth/WIFI End-to-End Embedded & Hardware Solutions I provide complete product development services — from concept and design through prototyping, firmware, and production — for IoT, wearables, medical, and consumer electronics. Hardware & PCB Design - Multi-layer PCB design for high-reliability, high-performance systems - High-speed design: USB 2.0, HDMI 2.0, DDR3/DDR4/LPDDR4, PCIe, NAND Flash, Ethernet (up to 10GBase-T1), PoE++ - Microcontrollers & SoMs: ARM Cortex-M3/M4 (STM32, ESP32, Nordic nRF52/53/91); custom boards for Raspberry Pi CM4, iMX8, Jetson Nano/Xavier/Orin, RK3588/3568, TI AM6254 - Power & analog: DC-DC (Flyback, Boost, Buck, LDO), BLDC/servo motor control, high-resolution ADC/DAC, audio circuits, and battery management (BMS) - DFM/DFA and EMC/EMI compliance, with certification support (CE, FCC, FDA-ready) - Tools: Altium Designer, KiCAD, Eagle, EasyEDA, OrCAD; SolidWorks and Inventor for 3D/enclosure design Firmware & Connectivity - Embedded software in C, C++, Python, and Qt, with RTOS integration and low-power optimization - Custom driver development and communication protocols: QSPI, I2C, SPI, RS485/RS232, CAN, Modbus (TCP/IP/RTU) - Connectivity stacks: BLE, Wi-Fi, NFC, LoRa/LoRaWAN, LTE, CAT-M1, NB-IoT, GSM (3G/4G) IoT platforms: MQTT, ThingsBoard, AWS IoT, Blynk; secure OTA updates, device provisioning, and cloud integration - Robotics: ROS/ROS2 for AGV, AMR, and 6-axis robot applications - Embedded UI/UX: Figma, TouchGFX, LVGL AI & Cloud Integration - Edge AI/ML deployment (Edge Impulse, TensorFlow Lite) - Predictive maintenance and anomaly detection for IoT/IIoT - Cloud integration with AWS, Azure, and Google Cloud - Cross-platform mobile apps (Android/iOS) and web dashboards for monitoring and analytics Product Leadership - Proven experience leading cross-functional teams in startup environments - End-to-end project management across design, fabrication, and procurement for cost-efficient, on-time delivery - Strong troubleshooting and research skills for electrical evaluation, testing, and design optimization 🔑𝐊𝐄𝐘𝐖𝐎𝐑𝐃𝐒: Embedded Design, Hardware Design, Firmware Development, Mobile App Integration, IoT Device, Medical Device Design, Embedded Systems, Real-time Operating Systems (RTOS), Microcontroller Programming, Sensor Integration, Wireless Communication (Bluetooth, Wi-Fi), Low Power Design, Wearable Devices, Firmware Architecture, Embedded Software, Device Drivers, System-on-Chip (SoC), PCB Design, Signal Processing, IoT Platforms, Cloud Integration, Mobile App Development, Web Portal Design, Healthcare Technology, Remote Monitoring, Data Security, Telemetry, ARM Cortex, ESP32, Device Connectivity, Embedded Prototyping, Human-Machine Interface (HMI), Medical Device Compliance, Mobile-Connected Devices, IoT Security, BLE, Firmware Debugging, Connectivity Solutions, Edge Computing, Smart Devices, Industrial IoT.

✅ TOP RATED PLUS (Top 3% Freelancer) Developer on Upwork, specializing in Mobile (Android native/Flutter). A pioneering and security-oriented developer offering more than 14 years of experience designing, implementing, integrating, testing and supporting impactful applications developed in diverse, collaborative environments for mobile and tablet devices on the mobile platform. WHY CHOOSE ME? ✅ 14+ Years of experience in Mobile Development ✅ 50 Finished Projects on Upwork, 100% Job Success ✅ 99% Clients who would recommend ⚡️ROCKSTAR IN: — Native Android/IOS Development — Hybrid Mobile Development - Flutter/React Native — Rust/NodeJS Backend Development ✅ Career Highlights - Developed numerous intuitive, visually engaging, and high-performance mobile applications that prioritize user experience and functionality. - Recognized for writing clean, efficient, secure, and reusable code, with a strong focus on privacy and data security. - Skilled in object-oriented design, data structures, problem-solving, performance optimization, and advanced debugging techniques. - Deep expertise in handling device compatibility and cross-version behavior across the mobile ecosystem. - Known as a self-driven, organized, and reliable developer who consistently meets deadlines and delivers quality work. - Provided technical leadership and mentorship to junior developers, helping elevate team performance. - Active contributor to the developer community with over 8,200 reputation points on Stack Overflow. 💬REVIEWS FROM CLIENTS: ⭐⭐⭐⭐⭐ "Phuoc Doan Hong is a true expert. His Kotlin knowledge and Android development experience are really valuable. I highly recommend this guy." ⭐⭐⭐⭐⭐ "He was an expert, in every move he made. Knowledgeable, patient and easy to communicate with. You can blindly trust him. Thanks again" ⭐⭐⭐⭐⭐ "Doan is highly skilled, smart, and works hard to find the best solution for complex problems. He has deep understanding of performance considerations in the Android platform. An Android expert. His English is excellent, and communication is great." ⭐⭐⭐⭐⭐ "I can simply say that I am very happy to work with him. He is very responsible, hardworking, and talented developer with great communication skills. He understood all the problems and delivered clear solutions. His skills and his professionalism are very high level. I am sure we will be working on new projects with him. Thanks for this amazing work!" Below you will find client reviews section, it describes the quality of work and value that you can expect from working with me

Are you looking for a Shopify developer who delivers clean code, fast results, and zero hand-holding? You've found them. I'm Levi — a Shopify specialist with 3+ years of hands-on experience building and optimizing Shopify stores for clients across Europe, North America, South Korea, and Australia. I don't just write code — I help e-commerce businesses convert more visitors into buyers. 🎯 Core expertise: — Shopify 2.0 theme development (Dawn, Prestige & custom themes) — Shopify App development — Liquid templating & advanced metafields / metaobjects — Theme customization & section building from Figma / PSD / XD — Speed optimization: lazy load, critical CSS, image compression — App integrations: Klaviyo, Wishlist Plus, Bundle apps, Store Locator — Bug fixing & layout/app conflict resolution — fast turnaround 💡 Going headless? I'm also confident with React, Next.js, Remix, Hydrogen, Tailwind CSS, Node.js, and TypeScript for custom storefronts. ✅ What sets me apart: — Responsive & deadline-driven: I treat your deadlines as my own — E-commerce UX/CRO mindset: every decision is made with conversion in mind — Clear communication: regular updates, no surprises — Detail-oriented: from pixel-perfect UI to clean, maintainable code Whether you need a full theme built from scratch, a tricky bug fixed today, or a conversion-focused redesign — I'm ready. 📩 Send me a message with your project details and I'll reply within a few hours.

💼 Profile Description Looking for a Shopify & Front-End Developer who can build a beautiful, fast, and high-converting store with any custom functionality? Try me! I’m a Front-End Developer & Shopify Expert with over 4 years of experience specializing in: +Building responsive and branded Shopify stores +Custom Shopify theme development and optimization +Managing product listings, titles, and SEO-friendly tags +Creating engaging visuals for product pages +Developing custom Shopify apps (using Remix / NodeJS) +Building modern front-end web applications with ReactJS, NextJS, and VueJS I focus on creating pixel-perfect, high-performance, and conversion-focused storefronts that deliver real results for your business. 🧠 Skills +Shopify (Liquid, Theme, App Development) – 4+ years +ReactJS – 4+ years +NextJS – 2 years +VueJS – 2 years +Shopify App (Remix) – 1.5 years +Front-End Performance Optimization +Responsive UI/UX Development 🛠 Services ✅ Shopify Store Development ✅ Shopify Theme Customization ✅ Shopify App Development ✅ Product Page Customization ✅ Shopify Product Upload & Management ✅ Front-End Development (ReactJS / NextJS / VueJS) ✅ Shopify Store Maintenance & Optimization 🌍 Selected Projects +youlockin.com +upfront.nl +theundone.com +fellaswim.com +international.fellaswim.com +reformebeauty.com +mercimaison.com +lebanoninnovate.com +cms.lebanoninnovate.com +frodz.qa +smartrestoration.com +blushbees.us +espadasymas.com +autorrautomocion.com +360haircare.com …and many more!