Modernizing Legacy Software with React, .NET, and Azure for Secure, User Centric Web Applications
Many legacy applications struggle with slow interfaces, fragile deployments, and security gaps that frustrate users and slow the business. We modernized a client’s legacy web platform by rebuilding the front end in React for a fast, component driven UI and migrating the backend to modern .NET (ASP.NET Core) running on Azure. The result is a secure, responsive, and user centric web experience that feels modern to end users while remaining maintainable for engineers.
Working incrementally with a strangler style migration, we replaced fragile monolithic pieces with well tested .NET microservices, containerized with Docker and deployed to Azure App Service (with options for AKS where needed). The React UI was built with an accessible component library and performance first patterns (code-splitting, server side rendering where appropriate), while authentication and authorization were hardened using Azure AD and token based flows. CI/CD pipelines, automated testing, and Application Insights logging were added to enable safe, frequent releases and fast troubleshooting. The project delivered measurable improvements in user satisfaction, faster page loads, stronger security posture, and dramatically reduced time to deploy and turning a risky legacy codebase into a scalable platform ready for future features.
Project Info
Client
WordPressRiver Themes
Date
25 February, 2022
Address
1401, 21st Street STE R4569, California
Background
Our client in the construction industry relied on a long-standing Classic ASP application to manage critical business processes such as resource handling, time reporting, and supplier invoice management. While the system had served well for years, it was becoming increasingly difficult to maintain, lacked scalability, and did not meet modern security or usability standards.
The client’s business operations were dependent on this application, which was still live with customers but had no dedicated test environment, creating significant risks for stability and innovation. Recognizing the need to modernize, the client partnered with us to rebuild the application using React for the frontend, .NET for the backend, and Microsoft Azure for deployment, while also migrating the legacy database to Microsoft SQL Server (MSSQL) for better performance and scalability.
The Challenges
Legacy Technology – The existing system was built in Classic ASP which limited scalability and integration with modern tools.
No Test Environment – Any modification in the old system risked downtime as it was directly live with customers.
Database Compatibility – The old database structure was outdated and required migration to MSSQL while preserving existing business data.
Limited Documentation – Much of the functionality lacked formal documentation
User Experience Limitations – The outdated UI was non-responsive and not aligned with modern usability standards and frustrating end-users.
Security Concerns – The old system lacked robust authentication and role management and compliance-ready data handling.
Solution
We executed a phased modernization strategy to minimize disruption while delivering maximum value:
Modern Tech Stack Adoption – Developed the frontend in React for a fast and responsive UI and the backend in .NET Core ensuring scalability and long-term maintainability.
Database Migration – Converted the old legacy database into MSSQL and restructuring it to improve query performance for security and reporting capabilities.
Cloud Deployment – Hosted the application on Microsoft Azure for leveraging its scalability and monitoring and security features for enterprise-grade reliability.
Progressive Migration Approach – Recreated functionalities using screenshots and workflows from the old system to ensure feature parity before introducing improvements.
UI/UX Redesign – Delivered a modern and user-centric design with intuitive navigation for mobile responsiveness and improved accessibility.
Security & Compliance – Integrated Azure Active Directory authentication for role-based access control and secure API endpoints to ensure compliance with modern security standards.
Future-Ready Architecture – Designed a modular system with APIs and services that allow new features like dashboards for advanced reporting and third-party integrations to be added seamlessly.