Verified Expert in Engineering
Duy has 20+ years of software development experience using Microsoft's technology stack, primarily with .NET. He builds high-quality and high-performance back-end systems and creates web applications with good UX using modern frameworks like Angular or React. Duy's proactive and results-oriented with a love of not only writing but also removing code to ensure efficient, stable, and flexible software is delivered within the projected scope and budget.
Agile, Visual Studio, .NET, C#, Windows, GitHub, Visual Studio Code (VS Code)
The most amazing...
...thing I've contributed to is an eCommerce platform where I can work with different modern technologies to help with optimization, stabilization, and extension.
- Worked as a technical supervisor for an offshore development team to ensure the quality of the code by doing peer reviews and applied unit and automation tests heavily.
- Contributed as a system architect or technical advisor to research and propose the best technical solutions that meet customer-specific requirements and feature enhancement while still being able to ensure system integrity and conformity.
- Built and led a high-performance team of senior developers to maintain and develop the eCommerce platform—the core product—with several versions developed in ASP Classic, ASP.NET Web Forms, ASP.NET MVC, React, .NET Core, Blazor, and more.
- Utilized React as a drop-in solution into the existing ASP.NET MVC application to enhance user experiences, flexibility, application performance, and throughput.
- Optimized front-end applications on both desktop and mobile devices using dynamic bundling and chunking system plus device-splitting solutions to minimize page loads as neatly as possible.
- Built and delivered a new version of platform back-end CMS (content management system) using Blazor (.NET Core).
- Applied and ran the development process smoothly using Agile, Scrum, and Kanban daily.
Offshore Development Lead
- Led a team of three offshore developers to maintain and develop more advanced features for a product that allows large organizations to control and publish their blueprints.
- Set up a CI/CD system using ThoughtWorks GO and MSBuild scripts to automate the build and deployment of the product. Developed SharePoint web parts to help show organization blueprint publications inside SharePoint, used as their ERP system.
- Developed a new version of a web-based publication wiki application where organization employees could sign in to see information and instructions about the processes, activities, regulations, and compliance they need to follow and perform.
- Implemented the SSO (single sign-on) function, which can be federated with the clients' organization corporate network seamlessly using Active Directory Federation Services (AD FS) and WIF.
- Integrated and built an extended identity provider service to allow sign-in with Google, Facebook, and LinkedIn using C#, WIF, and OpenAuth1/2.
- Constructed an on-demand infrastructure with AWS CLI and C# that would automatically scale up or down to serve multiple heavy operations simultaneously.
- Created an automated backup and restore system to improve product availability and fault tolerance. Built a centralized claim-based authentication and authorization system for the product using AD FS, C#, SAML1.1/2, WIF, and WCF.
- Incorporated WiX, XAML, and C# to build an installer of the whole product for customers who want to run their private version within their corporate network.
- Created and developed a remote logging system to synchronize logs from private installations of the product with a cloud-based logging system for more accessible support and diagnostics. Applied Agile and Scrum using Jira and Microsoft Excel.
DTT Globeteam Incorporation
- Led the team of around eight developers to build a product that helps large organizations to document, maintain, and publish their blueprints.
- Coordinated with clients for ideas and feedback to improve the product.
- Re-architectured and designed product based using Visio, UML, and Rational Rose.
- Ensured that ActiveX control is aligned and could run smoothly in various security scenarios within corporate networks.
- Developed a publishing system including a web-based application and publishing services to allow organizations to create an official publication of their blueprints.
- Created ClickOnce installation for WinForm application using Visual Studio.
- Used JIRA/MS Excel to apply Agile/Scrum into the development process.
DTT Globeteam Incorporation
- Worked closely with the project manager, QA lead, and customers to evaluate requirements; provide technical solutions; define SRS (software requirement specifications); and define scopes, milestones, and high-level iteration plans using MS Project and Microsoft Word/Excel.
- Coordinated with all team leads to work out detailed implementation plans for each and every iteration using MS Project and Excel.
- Set up and built a CI (continuous integration) system using TFS (Team Foundation Server) and Cruise Control.
- Built and developed core business services with ESB (Enterprise Service Bus) using C#, WCF (Windows Communication Foundation), XML, and SOAP.
- Built and set up a unit testing system to integrate into CI in order to ensure quality. Trained and embraced developers to create unit tests which eventually reached 55% code-coverage.
- Participated in recruiting and training new developers for project needs.
- Joined scrum review sessions every week with the project manager and customer to update them with status, progress and issues.
- Set up a network load-balancing system to improve the availability and performance of web-based applications that could serve thousands of concurrent users.
DTT Globeteam Incorporation
- Developed a rich and smart desktop-base PIM (Product Information Management) client application using C#, WinForms, Infragistics library, WCF (Windows Communication Foundation).
- Participated in designing an SOA (Service-oriented Architecture) for the whole system.
- Used WCF to build an ESB (Enterprise Service Bus) to serve as a generic message-based communication channel for all services and applications.
- Designed and built a dynamic form-based application using C# and XML which can easily be extended and modified to meet UI and UX requirements without having to change the codes.
- Widely applied asynchronous communications between end applications and services to give users the best experiences.
- Led a small team of six developers to work mostly on end applications.
- Coordinated with the services and databases team to ensure development priorities and planned are aligned together efficiently.
- Worked together with the QA team and customers to evaluate requirements, to review and continuously improve the application.
Faculty of Technologies, National University of Hanoi
- Developed and created a digital library for the faculty using Greenstone open-source software.
- Assisted in giving lectures to students in various areas of computer and information systems.
- Trained and supported students to work on a lot of small projects using C#, C/C++, VB, VB.NET, SQL, and ASM.
- Set up and worked on different internship projects with several government departments using Microsoft Access + VBA, PHP, MySQL, and .NET-based WinForms.
Data Technology Co. Ltd.
- Created production-level codes using both C++ and C# to build a unified communication system.
- Applied Agile methodologies to build a professional software development process that acted fast on changes and reduced time to live.
- Widely used and applied OOP/OOAD, design patterns/SOLID, and best practices.
- Built an interactive voice response system based on XML and VXML.
By adding more unit/automation tests, pair reviewing/programming refactoring and mentoring to build high-quality code, we have reduced support hours by 50% not only on the new versions but also on old versions of our e-commerce platform.
We have been tuning performance using RedGate ANTS profiling tools, using DI (Dependency Injection), caching, dynamic bundling, lazy loading, asynchronous loading to help increasing throughputs up to 45% and optimizing page loads by more than 60% to be around < 1s in average on all online shops.
I made it possible to embed Microsoft Office Applications such as Visio, Word, and Excel using C++/COM+/ActiveX to allow process owners to use ChangeDriver Editor as a unified tool/application for building their organization blueprints.
Based on WIF (Windows Identify Foundation) and with AD FS (Active Directory Federation Services), I was able to add SSO (Single-Sign-On) to ChangeDriver multi-tenancy system supporting federation with customer corporate networks, LinkedIn, Google, SharePoint.
Using ChangeDriver, organizations usually publish their blueprints for their employees to understand their processes and execute them accordingly. In order for being able to handle multiple large publications concurrently, I developed an auto scale-out publishing system with AWS EC2 CLI, WCF, .NET 4.0 multi-threading techniques.
I also created several powerful RESTful APIs to serve the data to not only present publications to organization employees but also to allow integration with organizations' ERP systems.
By using WCF (Windows Communication Foundation), SOAP/XML, self-made ESB (Enterprise Service Bus), we did build up a very flexible, highly scalable SOA (Service-oriented Architecture) system that helped property owners to easily enter vacation houses; contract partners to define flexible and multi-level pricing systems; end-users to search and book vacation houses through our load-balanced web applications; and reseller partners to do bi-directional synchronization with Vacasol databases.
For the last 1 year within the project, I did tune the performance a lot to allow loading property detail page and searching thousands of houses in less than 3 seconds.
.NET, ASP.NET, ASP.NET MVC, Windows Communication Framework (WCF), ASP.NET Web API, NUnit, ASP.NET Web Forms, Razor, Bootstrap, Classic ASP, .NET Core, MVC Razor, WIF, Blazor, Bootstrap 3, Entity, ActiveX, Redux, Swagger, Selenium, ASP, OAuth 2, ASP.NET Core, JSON Web Tokens (JWT), Windows Presentation Foundation (WPF), Angular, Windows PowerShell, Entity Framework Core
jQuery, REST APIs, Node.js, Web API, Entity Framework, React, Ajax Control Toolkit, Azure Blob Storage API, OpenID, jQuery UI, Amazon EC2 API, Infragistics
Visual Studio, GitHub, LLBLGen, MSBuild, ADFS, TFS, Visual SourceSafe, Git, Redux Thunk, Subversion (SVN), xUnit, WiX Installer, Dapper, Microsoft Project, Microsoft Excel, StringTemplate, Gulp, TeamCity, Docker Swarm, Figma
Agile, REST, Design Patterns, RESTful Development, Scrum, Extreme Programming, Continuous Integration (CI), Continuous Delivery (CD), Dependency Injection, Mobile Development, Service-oriented Architecture (SOA), Object-oriented Programming (OOP), Microservices, COM+
Windows, Visual Studio Code (VS Code), Telerik, Microsoft, SharePoint, Docker, Amazon EC2, Kubernetes, Amazon Web Services (AWS), Azure
Ajax, Back-end Development, Back-end, Web Development, Web App Development, Code Review, Source Code Review, Project Consultancy, Technical Leadership, Front-end Development, Web Services, RESTful Web Services, Microsoft 365, APIs, Microsoft Interop, Multithreading, DI, Single Sign-on (SSO), Software Consulting, Software Consultant, OAuth, Architecture, SAML-auth, Identity Server, Full-stack, Integration, Software Architecture, CI/CD Pipelines, Minimum Viable Product (MVP), UI Components, IIS, Remoting, CruiseControl, Oracle Service Bus (OSB), ClickOnce, DCOM, Active Directory Federation, VXML, Plugins, DevExpress
JSON, Microsoft SQL Server, SQL Server Management Studio, OpenXML, MySQL
Bachelor's Degree in Computing and Information System, Software Technologies
Faculty of Technologies, National University of Hanoi - Hanoi, Vietnam