Hire the Best Windows App Developers

✅ .NET Full Stack Developer 20+ years of experience ✅ Build powerful .Net solutions that drive business growth ✅ C# .Net developer with 15+ years of experience ✅ Developed 50+ applications ✅ Crafted 200+ user-friendly interfaces that drive real business results. The clients say "It doesn't feel like outsourcing, but instead like we have our own remote developers." "They had great soft and hard skills and were full of ideas and drive!" I lead the fullstack and mobile development team at Itexus, a professional software development and consulting company focused on Fintech, Insurance, Healthcare, etc. I have 20+ years of experience in the .net architect development of web and mobile applications, .net, python, node.js, java developer as well as javascript, react .net, angular, AI frameworks and libraries. 👨‍💻.NET Full Stack Expertise .NET full stack – strong background in End-to-end development from database to UI using Microsoft stack .NET Core – deep expertise, cross-platform backend services .NET Angular – Full stack development on .NET backend and Angular frontend for enterprise-grade solutions .net core angular – Building complete systems with seamless backend–frontend integration .NET Core Angular – Scalable and secure web apps using .NET Core and Angular Angular .NET solutions – Using Angular for UI and .NET for API and business logic .net core developer – Proven experience delivering high-performance backend solutions using .NET Core .net core react – Building robust, scalable web applications with .NET Core APIs and React frontends c# .net developer – End-to-end development expertise using C# and the .NET ecosystem c# .net core – Advanced solutions built on C# with .NET Core for modern, cross-platform applications 👨‍💻 BACKEND Development Python: Expert in Python for server-side development Frameworks: Proficient in Django and Flask for building web applications Databases: Skilled in SQL, PostgreSQL, MySQL, and MongoDB for efficient data management Architecture: Experienced in applying MVC patterns for scalable applications APIs: Capable of integrating external services through REST and GraphQL 👨‍💻 FRONT END Development Proficient in HTML5, CSS responsive, JavaScript Experienced in React.js, Angular, Vue.js, react native, ionic, xamarin developer Responsive, cross-browser, ui/ux designer, ux/ui dashboard, ui ux designer app 👨‍💻AI TOOLS OpenAI API, DeepFace, ML/DL frameworks (TensorFlow, Keras, PyTorch, Scikit-learn), LangChain, Mistral, AgenticAI, Transformers RAG + custom AI tools: Document recognition and processing, Market Grabber, project management bots, AI for telephony, video/audio analysis Mobile App Development Native Mobile Development: Android, Kotlin, Java, iOS, Swift, KMP, KMM. Cross-Platform/Hybrid App Development: Flutter, Swift, Objective C, React Native, Xamarin, MAUI. General Expertise Website & Full Stack Development: Full stack development with ai .net full stack developer, .net software engineer, .net programmer, full stack developer, ai python full stack developer django, full stack web developer, full stack development, cms developer DevOps/DevSecOps: AWS, Azure, Docker, Kubernetes, GitLab-CI, Ansible, Terraform, etc Cross-platform app building with three.js, web application design, webflow web designer, website builders Integration tools: Data integration, websockets, ABP Framework, discord, Autotask Experienced in .net core web api, fullstack .net developer roles, with strong skills as a .net specialist. Skilled angular .net react developer, java developer with solid c sharp expertise. Worked on kogito for business automation, delivered ui ux-focused solutions. As an azure data engineer, handled scalable data pipelines. rust developer, python projects include backend developer tasks. Built app as a xamarin and web developer using java and javascript. Skilled in postgresql and web scrapping. Maintained legacy systems with .net webform. Collaborated with nft marketers, managed nft collab manage tasks. Full stack with react nodejs, modern react, including react typescript, react native developer roles. Acted as product owner in agile teams. Cloud deployments done on azure. Built interactive UIs using blazor. Why Choose us Microsoft certified talented developers and senior .net developer team High QA standards, including qa engineer roles Modern solutions: NFT programmer, metaverse, Microsoft .net, windows 10, Power Apps developer, SharePoint, market grabber Scalable team: full stack software developer, front end programmer, ios developer, ui ux designer Industries Banking, Trading, Cryptocurrency, Asset Management, Lending, Retail, Real Estate & Property Management, Food Delivery, Entertainment, Hospitality, Construction, Sports & Fitness, Travel & Tourism, Wellness, Medical Dashboard, Marketplace, E-commerce, Automotive, Human Resources, Education, E-learning, AI Assistants Seek new projects to put our .net ai, bring value to individuals, startups, companies.

• Also known as Windows and macOS App Developer Expert • 5+ years of experience • I work on backend, frontend, databases, and Linux server administration • Main stack: .NET (C# / Visual Basic) and TypeScript / JavaScript • I build web and multi-platform desktop/mobile applications 📚 Technologies • My main tech stack is .NET (C# or Visual Basic .NET) and TypeScript / JavaScript • For .NET, I work with ASP .NET, Blazor, WPF, Windows Forms, MAUI (formerly Xamarin), Avalonia UI, and more • For TypeScript / JavaScript, I prefer React, but I can also work with Angular, jQuery, or vanilla JS • I can also develop macOS and iOS apps using Swift and Objective-C 🗼 Server Administration and DevOps • Familiar with Debian-based Linux distributions like Ubuntu • Able to handle VPS baremetal or Docker-based setups • Able to automate workflows using Bash, Python, GitHub Actions, and similar tools • Experienced with cloud services such as AWS and Azure 📊 Database • Microsoft SQL Server • MySQL / MariaDB • SQLite • PostgreSQL • Microsoft Access 💡 Skills • Strong in algorithm design and analysis • Great ability to solve programming and system trouble • Great at optimizing software performance • Flexible work style • Adaptive team player 📖 Self-Update • I regularly study new technologies to stay up to date. 🕰️ Flexible Availability • Open to collaborate across multiple time zones (US, CA, UK, EU, APAC, etc.) ✅ I’m not a robot. • I’m a real human and a solo freelancer, not an agency 🙌 Let’s Connect! • My name is Junian and I’d love to help bring your ideas to life • Feel free to reach out so we can discuss how I can support your project • Not a Vibe Coder, but use AI-Assisted Programming tools to solve problems • Linus Torvalds once said, “Talk is cheap. Show me the code.” So go ahead and check out my GitHub code. 🛠️ Common Tasks and Roles • Known as the Apple / macOS / iPhone guy • Build Windows app with .NET Framework & Windows Forms (WinForms) / Windows Presentation Foundation (WPF) / WinUI / Avalonia UI / MAUI / Xamarin • Build Windows Installer MSI / EXE from existing Windows App by using Wix / WixSharp • Build macOS app with Swift UI or .NET & Avalonia UI / MAUI / Xamarin • Build, sign, and notarize macOS app installer (PKG / DMG / ZIP) • Build web app with ASP .NET & Blazor / React / Angular / Vanilla JavaScript • Deploy and configure existing web apps by using Docker container to VPS / Cloud providers like AWS, Azure, or GCP • Ethical decompile / reverse engineer / source code retrieval / deobfuscation of existing .NET EXE / DLL / MSI or NinjaTrader Trading Indicator / strategy • Automate Windows UI tasks • Web scraping to retrieve online data / PDF / Images / any other files • Expert macOS system and app troubleshooting 🙋‍♂️ What I'm not • I'm not a Vibe Coder. Don't get me wrong, I use AI to build software, but I don't solely rely on it.

Senior .NET developer with 25+ years of hands-on experience working on real production systems. I help companies stabilize, modernize, and extend desktop and legacy .NET applications, taking ownership of existing codebases and delivering clean, maintainable solutions that work reliably long-term. Most of my work involves improving existing Windows desktop applications rather than building throwaway prototypes. I regularly take over mature or poorly documented systems, identify structural and stability issues, and extend functionality without disrupting production workflows. Clients usually come to me when a system is business-critical and needs careful, senior-level handling. My core expertise is in Windows desktop development using C#, WPF, WinForms, and the .NET Framework. I also have extensive experience supporting and modernizing legacy systems built with VB.NET, VBA, C++, and Delphi, including Office automation, custom installers, file system integration, and data-processing tools. For modernization and supporting services, I work with .NET Core, ASP.NET, Razor Pages, and REST APIs, which allows me to evolve legacy desktop systems, build internal web tools, or deliver complete end-to-end solutions when needed. I follow proven architectural practices such as MVVM, layered design, version control with Git, and predictable deployment processes. I’ve completed 120+ projects and 37,000+ hours on Upwork, working primarily on long-term and technically demanding systems where reliability, clarity, and ownership matter more than quick fixes. If you’re looking for a dependable senior .NET developer who can take responsibility for an existing system or build a stable desktop application from scratch, I’d be happy to discuss your project.

⭐⭐⭐⭐⭐ "𝘞𝘦 𝘸𝘦𝘳𝘦 𝘷𝘦𝘳𝘺 𝘩𝘢𝘱𝘱𝘺 𝘸𝘪𝘵𝘩 𝘵𝘩𝘦 𝘨𝘳𝘦𝘢𝘵 𝘸𝘰𝘳𝘬 𝘲𝘶𝘢𝘭𝘪𝘵𝘺 𝘈𝘯𝘯 𝘱𝘳𝘰𝘷𝘪𝘥𝘦𝘥 𝘢𝘯𝘥 𝘵𝘩𝘦 𝘕𝘢𝘵𝘪𝘧𝘦 𝘔𝘰𝘣𝘪𝘭𝘦 𝘵𝘦𝘢𝘮. 𝘐𝘧 𝘸𝘦 𝘳𝘦𝘲𝘶𝘪𝘳𝘦 𝘢𝘯𝘺 𝘸𝘰𝘳𝘬 𝘢𝘨𝘢𝘪𝘯, 𝘸𝘦 𝘸𝘪𝘭𝘭 𝘥𝘦𝘧𝘪𝘯𝘪𝘵𝘦𝘭𝘺 𝘶𝘴𝘦 𝘵𝘩𝘦𝘮." 🤝 𝐈 𝐜𝐨𝐝𝐞, 𝐚𝐝𝐯𝐢𝐬𝐞, 𝐚𝐧𝐝 𝐜𝐚𝐫𝐞 𝐟𝐨𝐫 𝐲𝐨𝐮𝐫 𝐩𝐫𝐨𝐝𝐮𝐜𝐭 𝐥𝐢𝐤𝐞 𝐢𝐭’𝐬 𝐦𝐢𝐧𝐞 𝐟𝐫𝐨𝐦 𝐭𝐡𝐞 𝐬𝐭𝐚𝐫𝐭. 👋 Hi! I’m Ann an Android & iOS mobile app developer Swift Kotlin mobile app development expert with 8+ years of experience building high-performance iOS apps, Android apps, and scalable cross-platform solutions with React Native. 🚀 Android & iOS Mobile App Developer | Swift • Kotlin • React Native | Mobile App Development As a Top Rated Plus Android & iOS mobile app developer Swift Kotlin mobile app development specialist on Upwork with 30+ five-star reviews and a 100% Job Success Score, I’ve helped 60+ companies and startups transform ideas into scalable, future-proof mobile products. Whether you need a native iOS app with Swift, a native Android app with Kotlin, or a cross-platform solution, I deliver Android & iOS mobile app development using Swift and Kotlin with precision, creativity, and enterprise-grade quality. From e-commerce, fitness, and healthcare to fintech, streaming, logistics, and wearable apps, my experience as an Android & iOS mobile app developer Swift Kotlin mobile app development professional spans 15+ industries and 50+ published apps. ✅ Why Partner with Me as Your Android & iOS Mobile App Developer: 8+ years of hands-on Android & iOS mobile app development using Swift, Kotlin, React Native 50+ successful iOS and Android apps delivered in Fitness Mobile App (Coaches, Gyms & AI Meal Plans) 10+ successful iOS and Android apps delivered in Fintech industry A strong mobile app development team of 50+ experts 100% Job Success Score and consistent 5-star reviews on Upwork Streaming, TV apps GPS and Map-based apps ( GPS trackers, MapBox, Google Maps integration) AI Mobile App Development MVP App Development for Wellness and Hospitality Platform Dating Mobile App Social Media App Development Mental Health Social Platform Enhance an Android, IOS mobile apps Figma designer. UX/UI designer Real Estate mobile apps Full-cycle Android & iOS mobile app development — from idea to App Store & Google Play launch AI App Expert specializing in Swift Kotlin mobile app development, on-device ML, real-time image & text processing, and LLM API integrations 🔧 Services I Provide as an Android & iOS Mobile App Developer (Swift & Kotlin): Native iOS app development with Swift & SwiftUI Native Android app development with Kotlin & Jetpack Compose Android & iOS mobile app development using Swift Kotlin architecture React Native app development for cross-platform solutions UI/UX design for iOS and Android apps (Figma, Sketch, Adobe XD) Secure API integrations & cloud services (AWS, Google Cloud) Scalable backend connections & microservices Wearable app development (Apple Watch, Wear OS, Bluetooth) Performance optimization & offline-first mobile app development 🎯 Industries I Specialize In as an Android & iOS Mobile App Developer (Swift Kotlin): 📦 E-Commerce | 🍔 Food & Drink | 📚 Education 💪 Health & Fitness | 💘 Dating | 🎬 Entertainment & Streaming 💼 Finance & Banking | 🌍 Travel | 📱 SaaS Platforms ⌚ Wearables & IoT | 🚚 Logistics & Booking Apps All powered by Android & iOS mobile app development with Swift and Kotlin. 🚀 Advanced Features I Build with Swift & Kotlin Mobile App Development: ✔️ Social login (Google, Apple, LinkedIn) ✔️ Real-time chat, WebRTC video calls & push notifications ✔️ Offline mode & smart data synchronization ✔️ GPS, geolocation, Bluetooth & geofencing ✔️ ARKit & advanced AR features ✔️ Firebase & cloud integrations ✔️ Monetization (AdMob, Meta Ads) ✔️ Voice assistants (Siri, Google Assistant, Alexa) ✔️ TV apps (tvOS, Android TV) & wearable tech (Garmin, Monkey-C) 💬 Why Choose Me as Your Android & iOS Mobile App Developer (Swift Kotlin): I bring deep expertise in Android & iOS mobile app development using Swift and Kotlin, focusing on clean architecture, scalability, performance, and business impact. Whether you’re a startup building an MVP or an enterprise scaling globally, I’m the Android & iOS mobile app developer Swift Kotlin mobile app development expert who can turn your vision into a successful product. 📱 Let’s connect and build a powerful Android & iOS mobile app with Swift and Kotlin. 🚀 Your trusted Android & iOS mobile app developer Swift Kotlin mobile app development partner is just one click away. UPD: 05.06.2026

I'm a senior .NET developer with over 12 years on Upwork, specialising in Windows desktop applications, legacy system work, and business integrations across the Microsoft stack. My background is broad, but where I'm most useful is on the harder projects — undocumented codebases, legacy migrations, ERP integrations, and end-to-end delivery of complex Windows software. These are the kinds of projects I've built a reputation around. A recent example: I designed and built a full Windows Assistant platform using WPF — combining video capture, SharePoint content management with a Windows Explorer-style interface, a locally cached SQLite database with a background sync service, and a Web API built on a clean services/infrastructure architecture over Entity Framework Core and SQL Server. The system included SignalR real-time notifications, JWT authentication, and integrations with Vimeo, Twilio, SmileBack and others, alongside a complete MVC admin portal. What I work on: Legacy systems — VB6, Visual FoxPro, VB.NET, WinForms, WPF. I regularly take on codebases other developers decline, and I'm comfortable working in undocumented or inherited code. ERP and business integrations — SAP, SAGE, MYOB, SQL Server, Oracle, Shopify, DocuSign, Amazon API and more. I've worked across insurance, logistics, and enterprise clients and understand how business-critical systems need to behave. I ask the right questions before I start, flag issues early, and deliver on time. Clients tend to come back for that as much as the technical work. Tech I work with: WPF · WinForms · C# · .NET / ASP.NET · WCF · Entity Framework Core · SQL Server · Oracle · SQLite · SignalR · JWT · REST APIs · SharePoint · MS Office Add-ins · SAP · SAGE · MYOB · VB6 · VB.NET · Visual FoxPro · Shopify · DocuSign · Amazon API · Vimeo · Twilio · MVC

Hello, I’m Jason Nhien Truong, a Senior Software Engineer and Software Architect with over 20 years of professional experience delivering reliable, maintainable software solutions for businesses across multiple industries. I specialize in C# and .NET development, Windows desktop applications, enterprise web systems, SQL databases, and Azure-based platforms. I help clients modernize legacy systems, stabilize and scale existing products, and build new applications with a strong focus on performance, usability, and long-term maintainability. I work closely with stakeholders to translate business needs into practical, well-structured technical solutions. What I offer Full-stack .NET development I work across the .NET ecosystem, from legacy ASP.NET Web Forms to modern .NET 8 APIs and microservices. I design secure, scalable backend systems with clean architecture and clear separation of concerns. Windows desktop application development I have extensive experience building and maintaining Windows desktop applications using WinForms and WPF, including MVVM-based WPF applications. I focus on responsive UI behavior, clean data binding, maintainable ViewModel design, and user-friendly workflows for business-critical desktop software. Enterprise UI with DevExpress and Telerik I have deep expertise with DevExpress and Telerik controls for WinForms and web applications. I redesign and modernize complex UIs to improve usability, consistency, and performance without breaking existing business logic. Database architecture and optimization Strong experience with SQL Server, PostgreSQL, MySQL, and Azure SQL. I design schemas, optimize queries, and ensure data integrity and stability in production systems. Azure cloud and DevOps Hands-on experience deploying and maintaining applications on Azure, including CI/CD pipelines, containerized services, background processing, and cloud-based integrations. Testing and automation I write unit and integration tests using xUnit and NUnit, and implement automation with Selenium and AutoIt to improve quality and reduce regression risk. Key technical skills Languages and platforms C#, .NET Core, .NET 8, ASP.NET, SQL, JavaScript, HTML, CSS, Python Desktop development WinForms, WPF, MVVM, DevExpress WinForms, Telerik UI Frameworks and tools Entity Framework, LINQ, Docker, Azure DevOps Databases SQL Server, PostgreSQL, MySQL, MongoDB, Azure SQL Cloud and monitoring Azure, Kubernetes, Azure Service Bus, Prometheus, Grafana Architecture Microservices, Clean Architecture, Domain-Driven Design Selected projects Web forecasting application maintenance Maintained and enhanced a legacy ASP.NET Web Forms application using SQL Server 2022 and Telerik UI. Improved UI workflows, business logic, and performance. Betx – cloud-native microservices platform Developed backend microservices using .NET 8 and Web API. Worked on PostgreSQL data modeling, Azure Kubernetes deployment, secure APIs, messaging, and observability with Prometheus and Grafana. Custom ERP system for manufacturing Built a custom ERP system using C# and SQL Server, including workflows, reporting, role-based access, and third-party integrations. Carrier pricing API integration Integrated FedEx and UPS APIs for real-time pricing, data synchronization, and robust error handling with retries and logging. Why work with me I bring deep technical experience, strong ownership, and a business-focused mindset. I communicate clearly, meet commitments, and build software that remains stable and maintainable over time. Availability Open to full-time or part-time engagements. Flexible with time zones for long-term projects. If you’re looking for a senior .NET engineer who can handle both backend systems and Windows desktop applications with confidence, feel free to reach out.