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I am a tech professional with a Bachelor of Science in Information Technology and a strong foundation in software development, data structures, system analysis, and technical problem-solving. I focus on building practical, efficient solutions and improving user experience through careful attention to detail. I am adaptable, reliable, and quick to learn new tools, technologies, and workflows based on project requirements. My background allows me to support a wide range of technology-related tasks, including coding, troubleshooting, research, data-related work, QA testing, web/app review, and technical support. I can work independently or as part of a team, communicate clearly, and deliver results with accuracy and consistency. If you are looking for a motivated and dependable professional to support your project, I would be happy to help.

A results-driven software engineer with five years of expertise in full-stack development, specializing in .NET and modern web technologies. Proven track record in delivering scalable solutions across payment systems, insurance, and e-commerce domains. Committed to Agile methodologies and technical excellence.

𝗜 𝗛𝗲𝗹𝗽 𝗙𝗼𝘂𝗻𝗱𝗲𝗿𝘀 𝗩𝗮𝗹𝗶𝗱𝗮𝘁𝗲 𝗕𝗲𝗳𝗼𝗿𝗲 𝗧𝗵𝗲𝘆 𝗕𝘂𝗶𝗹𝗱 — 𝗦𝗼 𝗧𝗵𝗲𝘆 𝗗𝗼𝗻’𝘁 𝗪𝗮𝘀𝘁𝗲 𝗧𝗶𝗺𝗲 𝗢𝗿 𝗠𝗼𝗻𝗲𝘆 𝗕𝘂𝗶𝗹𝗱𝗶𝗻𝗴 𝗧𝗵𝗲 𝗪𝗿𝗼𝗻𝗴 𝗣𝗿𝗼𝗱𝘂𝗰𝘁 🚫⏳ 🚫💸 🚫 Not just prototypes. 🚫 Not just demos. ✅ Real products that can grow. Over the last 7+ years, I’ve been working as a full-stack engineer and backend architect building SaaS platforms, AI tools, and automation systems for startups and product teams. 🏆 I’m also a 𝗧𝗼𝗽 𝗥𝗮𝘁𝗲𝗱 freelancer on Upwork trusted by companies across: • 🇺🇸 United States • 🇦🇺 Australia • 🇨🇦 Canada • 🇸🇬 Singapore • 🌏 Southeast Asia ━━━━━━━━━━━━━━━━━━ 🚀 𝗪𝗵𝗮𝘁 𝗜 𝗱𝗼 𝗯𝗲𝘀𝘁 I build AI-powered SaaS products and scalable platforms from idea to production. Typical journey I support: ⚡ Concept → MVP → Production → Scale Many founders reach out to me when they are building: ◆ 🤖 AI SaaS platforms ◆ 🧠 LLM-powered applications ◆ ⚙️ automation systems ◆ 🏪 SaaS marketplaces ◆ 📈 scalable startup platforms ◆ 🏢 enterprise web applications My focus is always the same: build stable systems that support real users. ━━━━━━━━━━━━━━━━━━ 🤖 𝗔𝗜 𝘀𝘆𝘀𝘁𝗲𝗺𝘀 𝗜 𝗯𝘂𝗶𝗹𝗱 ◆ 🧠 LLM applications powered by OpenAI ◆ 🔎 RAG pipelines for knowledge systems ◆ ⚡ AI automation workflows ◆ 🎯 AI recommendation & matching engines ◆ 📄 document AI and semantic search systems These are not experimental demos. They are designed for real production products. ━━━━━━━━━━━━━━━━━━ 🏗 𝗙𝘂𝗹𝗹-𝘀𝘁𝗮𝗰𝗸 𝗮𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗲 My development philosophy is backend-first engineering. I focus on systems that are: ⚡ scalable 🧱 maintainable 🚀 high-performance 🔐 secure ━━━━━━━━━━━━━━━━━━ ⚙️ 𝗕𝗮𝗰𝗸𝗲𝗻𝗱 𝘀𝘁𝗮𝗰𝗸 ◆ ASP.NET Core (.NET 6+) ◆ Node.js ◆ NestJS Architecture: ◆ Clean Architecture ◆ SOLID principles ◆ Microservices systems ◆ CQRS & MediatR patterns Infrastructure: ◆ Hangfire — background processing ◆ SignalR — real-time systems Data layer: ◆ PostgreSQL ◆ SQL Server ◆ Redis caching ◆ FusionCache two-level caching Security: ◆ JWT authentication ◆ OAuth integrations ◆ Role-based authorization (RBAC) DevOps: ◆ CI/CD pipelines ◆ GitHub Actions ◆ Azure DevOps ━━━━━━━━━━━━━━━━━━ 🎨 𝗙𝗿𝗼𝗻𝘁𝗲𝗻𝗱 𝘀𝘁𝗮𝗰𝗸 ⚛ React ⚡ Next.js 📘 TypeScript UI systems: ◆ TailwindCSS ◆ Material UI ◆ Ant Design Focus areas: 🚀 performance optimization 📊 SEO optimization ⚡ scalable frontend architecture ━━━━━━━━━━━━━━━━━━ 🎯 𝗪𝗵𝗲𝗿𝗲 𝗜 𝗮𝗱𝗱 𝘁𝗵𝗲 𝗺𝗼𝘀𝘁 𝘃𝗮𝗹𝘂𝗲 Many founders contact me when: ◆ their MVP is unstable ◆ their product is half-built ◆ their previous developer disappeared ◆ their system cannot scale ◆ their AI prototype needs real engineering Often the product started with tools like: ◆ v0 ◆ Lovable ◆ Replit ◆ no-code builders That’s completely fine. But when the system needs real architecture, performance, and stability, I step in to rebuild or scale it properly. ━━━━━━━━━━━━━━━━━━ 📊 𝗥𝗲𝘀𝘂𝗹𝘁𝘀 𝗜’𝘃𝗲 𝗱𝗲𝗹𝗶𝘃𝗲𝗿𝗲𝗱 📈 SaaS platforms used by 10,000+ users ⚡ reduced API latency by 70% using Redis caching 🤖 AI automation systems saving teams 20+ hours per week 🚀 delivered startup MVPs in 4–8 weeks ━━━━━━━━━━━━━━━━━━ 𝗛𝗼𝘄 𝗜 𝘄𝗼𝗿𝗸 Clients enjoy working with me because I think like a product engineer, not just a coder. My approach: 🗣 clear and direct communication 🧠 architecture-first thinking 💰 business-driven technical decisions 💡 proactive product suggestions 📈 long-term scalability mindset ━━━━━━━━━━━━━━━━━━ 𝗜 𝗱𝗼𝗻’𝘁 𝗷𝘂𝘀𝘁 𝘄𝗿𝗶𝘁𝗲 𝗰𝗼𝗱𝗲. I design systems that support real users, real traffic, and real business growth. ━━━━━━━━━━━━━━━━━━ If you're building an AI SaaS or startup product, feel free to reach out. Send me a message with: 💡 your idea 🧱 your current progress ⚠ the biggest technical challenge you’re facing I’ll tell you honestly whether I can help and how we can move forward.

✅ Top-Rated Senior Developer ✅ 100% Job Success Score ✅ Available for part-time, full-time long-term projects on Upwork (up to 40+ hours/week) ✅ Government ID Verified ✅ Professional Experience ✅ Expertise in .NET-based Web Applications, RESTful APIs, SPA architectures, CMS solutions, and enterprise-grade systems I’m a Senior Full-Stack .NET Developer with 6+ years of hands-on experience delivering and optimizing production-ready applications using C#, ASP NET / .NET Core, ABP Framework, and frontend technologies such as Angular, React, and modern JavaScript frameworks. I work across both backend and frontend, focusing on APIs, database design, performance optimization, and building responsive, user-friendly interfaces. What I Help You With - Custom web applications & system upgrades - Secure, efficient API integrations - Performance optimization & code refactoring - Long-term maintenance & scalability improvements Technical Expertise - Backend: C#, ASPNET MVC/Core, Web API, EF/EF Core, ABPio - Frontend: Angular, React, Vue, Blazor WASM, Nextjs, Tailwind, Telerik/Kendo UI - Databases: SQL Server, Azure SQL, MySQL, PostgreSQL, MongoDB - Cloud & Tools: AWS, Azure, Git, Visual Studio, CI/CD - Platforms: Windows Server, Linux, macOS Why Choose Me ✔ Clean, scalable, and maintainable code ✔ Fast delivery without sacrificing quality ✔ Client-focused communication ✔ High-performance, real-world applications ✔ Money-back guarantee & long-term discounts Availability 🕒 Part-time or Full-time (40+ hrs/week) | Ready to start immediately 💬 Response within 1 hour | Flexible time zones 👉 Click “Hire Now” or “Invite to Interview” to get started. Best regards, Le Xuan Thuan

Legacy .NET Framework app? Slow SQL Server queries? I migrate ASP.NET MVC applications to .NET 8/10 and optimize the databases behind them, safely, incrementally, without breaking production. I'm a Senior .NET Engineer and Technical Lead with 14+ years in enterprise C# .NET, React, and SQL Server. Most recently I led a team of 8 engineers on Wellbarrier, an enterprise SaaS platform delivered to SLB and used by major oil & gas operators worldwide. It's a large, long-lived codebase built across 4 Scrum teams. Legacy systems, complex data models, and production systems that can't afford downtime are my home ground. ━━━━━━━━━━━━━━━━━ WHAT I HELP WITH ━━━━━━━━━━━━━━━━━ 1️⃣ LEGACY .NET MODERNIZATION & UPGRADES ▪️ ASP.NET MVC on .NET Framework 3.5 / 4.x to ASP.NET Core / .NET 6, 8, 10 (LTS), including the 3.5 to 4.8 upgrade step for very old codebases ▪️ Entity Framework 6 to EF Core: mapping changes, query behavior differences, and data-layer refactoring ▪️ Legacy front ends (Razor, jQuery, AngularJS) rebuilt in modern React ▪️ Every migration starts with an assessment: dependency audit, breaking-change map, and a phased plan, so you know the real cost and risk BEFORE the work begins 2️⃣ DATABASE DESIGN & OPTIMIZATION (SQL SERVER) ▪️ Schema design for new products, plus redesign of data models that grew messy over the years ▪️ Rescuing slow queries, timeouts, and heavy reports: indexing, query tuning, execution plan analysis on large production datasets 3️⃣ NEW FEATURES FROM SCRATCH, FROM SPEC TO SHIPPED ▪️ Certified Scrum professional (PSM I, PSD I, PAL I, SPS from Scrum•org). I turn a rough idea into user workflows, acceptance criteria, and a sprint-ready backlog, then build it in C# .NET and React ▪️ Ideal if you have a product vision but no written requirements yet ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ WHY CLIENTS WORK WITH ME ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ▪️14+ years of hands-on development, with international clients since 2012 across e-commerce, recruitment, oil & gas, and SaaS ▪️4+ years leading engineers: architecture decisions, code reviews, mentoring, sprint planning ▪️Enterprise discipline: clean code, unit testing, CI/CD, Git, refactoring without breaking existing behavior ▪️Clear written communication and reliable delivery across time zones. I typically respond within a few hours. ━━━━━━━━━━━━━━━━━━━ HOW WE CAN START ━━━━━━━━━━━━━━━━━━━ ▪️Small first: a fixed-price migration assessment, a database performance audit, or a feature specification package. You get a concrete deliverable and see exactly how I work. Then we scale up to the full migration, the new feature, or a long-term engagement. ▪️Available full-time, for focused projects or long-term contracts. ▪️Message me with your current .NET version, database, and main pain point, and I'll reply with an honest first take on the best path forward.

Are you looking for a developer who can turn your ideas into scalable, production-ready software? I am a Senior Full-Stack Developer with 10+ years of experience building enterprise applications, SaaS platforms, AI-powered solutions, desktop software, and mobile applications for clients worldwide. Beyond hands-on development, I also lead a cross-functional software engineering team of 7 professionals, enabling us to deliver projects efficiently from requirements gathering to production deployment. Our team includes Full-Stack Developers, a Solution Architect, Mobile Developers, a QA Engineer, and a Technical Team Lead with strong DevOps expertise. This structure allows us to provide end-to-end software delivery while maintaining high quality, scalability, and reliability. I specialize in designing and developing end-to-end systems—from architecture and backend APIs to modern web and mobile frontends. Whether you need a new product built from scratch, an existing system modernized, or AI integrated into your business workflow, I can help. 🔹 What I Bring to Your Project ✅ Full-Stack Development • ASP.NET Core • ASP.NET MVC • Web API • Blazor (Server & WebAssembly) • C# • JavaScript / TypeScript • HTML5 / CSS3 / SCSS • Bootstrap ✅ Cloud & Architecture • AWS • Google Cloud Platform (GCP) • Microservices Architecture • RESTful APIs • Event-Driven Systems • CI/CD Pipelines ✅ AI & Automation • OpenAI (GPT) • Azure AI Services • Google Cloud AI • Hugging Face • AI Chatbots • Document Processing • Intelligent Workflow Automation • Retrieval-Augmented Generation (RAG) ✅ Mobile & Desktop Applications • .NET MAUI • Xamarin • React Native • Windows Forms • WPF ✅ Databases • SQL Server • PostgreSQL • MongoDB • SQLite • Neo4j ✅ Quality & DevOps • xUnit • Git • GitHub • GitLab • Jira • Agile / Scrum 🔹 Industries & Solutions Throughout my career, I have worked on: • Enterprise Management Systems • Manufacturing & Industrial Automation • IoT Monitoring Platforms • GIS & Mapping Applications • AI-Powered Business Solutions • Workflow Automation Systems • Customer Portals & SaaS Products • Mobile Business Applications 🔹 Why Clients Work With Me ✔ Senior-level technical expertise ✔ Dedicated software delivery team available when projects scale ✔ Strong communication and transparency ✔ Clean, maintainable, scalable code ✔ Business-focused mindset ✔ Fast learning and problem-solving skills ✔ Long-term support and commitment ✔ Reliable delivery with attention to quality I don't just write code—I help businesses build software that creates real value. Let's discuss your project and find the best solution together. 📩 Feel free to invite me to your job or send a message. I look forward to working with you.