I'm a Full-Stack C#/.NET Developer with 3+ years of experience building
web applications, WinForms desktop apps, REST APIs, and SQL Server solutions.
I handle both back-end logic and front-end integration using HTML, CSS,
JavaScript, and jQuery to deliver complete, user-friendly applications.
What I can help you with
- Build or fix .NET Core / .NET Framework applications
- Develop REST APIs following clean architecture
- Design, optimize, and troubleshoot SQL Server (queries, functions, stored procedures)
- Create or customize DevExpress components (WinForms / Web)
- Debug and fix existing C# projects
- Improve performance and refactor legacy systems
- Front-end support using HTML, CSS, JavaScript, and jQuery
Why clients choose me
- Fast and clear communication
- Reliable, detail-oriented, and responsible
- Clean, well-documented, maintainable code
- Strong problem-solving mindset
Let's discuss your project needs—whether it's a quick fix or full-scale development, I'm here to help.
📩 Available to start immediately
⚡ Usually respond within 1 hour
💬 Clear communication in English (written preferred, calls available)
C#
.NET Framework
ASP.NET
Microsoft SQL Server
REST API
HTML
CSS
JavaScript
Windows Forms
jQuery
Wix
Landing Page
Web Design
Responsive Design
Figma
NHIEN T.
Ho Chi Minh City, Vietnam
$30/hr
4.6
30 jobs
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.
DevExpress
C#
ASP.NET Core
JavaScript
Entity Framework
React
Microsoft SQL Server
Microsoft Azure
Python
nopCommerce
Blazor
Machine Learning
Thanh L.
Hanoi, Vietnam
$25/hr
5.0
23 jobs
I’m a Senior .NET Developer combined with a Business Analyst mindset, with 10+ years of experience delivering and rescuing business-critical systems.
I don’t just develop features — I analyze business workflows, fix system bottlenecks, and deliver scalable solutions that actually improve operations.
In addition, I bring strong UI/UX implementation skills, allowing me to turn designs into pixel-perfect, production-ready interfaces — ensuring both performance and user experience.
🏆 Top Rated Freelancer
🏆 100% Job Success Score
💰 $10,000+ Earned
🚀 What I Specialize In
🔹 ERP / CRM / Business Systems Development
Design and build systems for Sales, HRM, Warehouse, Manufacturing, Fleet Management
Translate business requirements into scalable technical solutions
🔹 Legacy System Modernization (.NET)
Upgrade old systems (.NET MVC, WebForms) → .NET Core / Blazor
Refactor messy codebases into maintainable architectures
Improve system performance, stability, and scalability
🔹 System Performance Optimization
Fix slow systems (database queries, API latency, UI rendering)
Optimize SQL, backend logic, and frontend performance
🔹 Pixel-Perfect UI Development (Figma / Adobe → Code)
Convert Figma / Adobe XD / Photoshop designs into responsive HTML/CSS
Ensure pixel-perfect accuracy across devices and browsers
Implement UI using Blazor, DevExpress, Telerik
🔹 Business Analysis + Technical Execution
Analyze workflows and suggest better system design
Reduce operational inefficiencies through smart automation
💡 Why Clients Hire Me
I think like a business owner, not just a developer
I can quickly understand complex legacy systems and take ownership
I proactively identify risks, bottlenecks, and better approaches
I communicate clearly and provide regular progress updates
🧠 Tech Stack
Backend: C#, .NET Core, ASP.NET MVC, Web API, Entity Framework
Frontend: Blazor, HTML, CSS, JavaScript, Bootstrap, jQuery
UI Frameworks: DevExpress, Telerik (Kendo UI), Syncfusion
Database & Data: SQL Server, PL/SQL, OLAP, MDX
Other: Python, ETL, Power BI, Excel, .NET MAUI
🎯 Productized Services (Fixed Scope – High Value)
💼 ERP / CRM System Audit – from $200
- Review architecture, database, and workflows
- Identify bottlenecks & risks
- Provide actionable improvement plan
⚡ Fix Slow .NET System – from $300
- Analyze performance issues (SQL / API / UI)
- Optimize response time and system stability
- Deliver measurable improvements
🔧 Legacy System Upgrade (.NET MVC → .NET Core / Blazor)
- Codebase assessment
- Migration strategy
- Step-by-step modernization plan
📊 Database & Query Optimization – from $150
- Analyze slow queries
- Optimize indexes and execution plans
- Improve overall system performance
📌 Best Fit Clients
- Companies running old .NET systems with performance issues
- Businesses needing ERP / HRM systems built or improved
- Founders who want a developer that understands business, not just code
💬 Let’s Work Together
If your system is slow, hard to maintain, or no longer fits your business — I can help you analyze, fix, and upgrade it efficiently.
DevExpress
ASP.NET MVC
Web Application
Bootstrap
.NET Core
MVC Framework
Database Design
Telerik
Front-End Development
Data Analysis
Business Analysis
PCB Design
Software Development
System Analysis
Digital Transformation
Software
HUYNH L.
Hcm, Vietnam
$35/hr
5.0
139 jobs
I am a software developer with 20 years of experience. I have experiences in warehouse, accounting, retail/wholesale, bar code technology, customer management, loyalty, tablets (Android, iOS), web service, SQL, Office VBA, DevExpress, custom Xtrareport design, Amazon SP-API, Best Buy API, Macys API, Walmart API, Google Sheet... I already finished many projects for our customers about these fields successfully.
My free time about 30 hours/week and I would like to find some extra jobs to work in that time.
DevExpress
C#
.NET Framework
Amazon Web Services
Ionic Framework
eBay API
Angular 6
Transact-SQL
Mac OS App Development
Google Chrome Extension
SQL Programming
Amazon API Gateway
HTML5
Entity Framework
Apps Script API
Danny N.
Hanoi, Vietnam
$25/hr
5.0
6 jobs
PROFESSIONAL SUMMARY
* 7-years+ of experience in software development.
* 7-years+ of experience in Back-end development, mastering C#, ASP .Net, ASP .Net Core.
* 5-years+ of experience in Front-end development, mastering ReactJs, VueJS
* 4-years+ of experience as a Team Leader.
* 2-years+ of experience as a Technical Leader.
* 1-year+ of experience as a Project Manager.
* Love solid, kiss, dry, demeter, tda, soc, yagni, functional programming.
* Proficient in Git and have the ability to work with Git Flow, Release Flow.
* Scrum/Agile mindset.
* Working as a team is my main working style.
* Willing to learn any new technologies.
C#
SQL
TypeScript
Redis
Entity Framework
Elasticsearch
Azure DevOps
React
Blazor
JavaScript
NoSQL Database
.NET Core
Service Cloud Development
SOAP
AWS CodeDeploy
Viet N.
Ho Chi Minh, Vietnam
$60/hr
5.0
48 jobs
◈ Top Rated Plus freelancer with 100% Job Success on Upwork
◈ More than 17 years of experiences using Microsoft tech stack to develop Web, Mobile and Windows based applications, with strong analytical skills and a broad range of computer expertise.
◈ An excellent problem-solver, able to quick grasp complex systems and identify opportunities for improvements and resolution of critical issues.
◈ Dynamic and committed in continue gaining knowledge of the business domain and latest technologies
◈ Excellent team player, skilled in enlisting the support of all team members in aligning with project and organizational goals.
ASP.NET MVC
C#
Windows Communication Foundation
Windows Presentation Foundation
Microsoft SQL Server
.NET Core
Microsoft Silverlight
Unit Testing
XAML
Angular
React
Node.js
API Development
Python
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