Full-Stack Legacy Modernization: From .NET to Modern Cloud-Native Architecture

An agricultural commodity brokerage relied on an aging .NET/SQL Server web application to manage grain marketing operations for 100+ clients across the U.S. Midwest. The legacy platform suffered from critical usability and technical issues: the forgot-password flow was broken (requiring manual admin resets), page loads triggered 500+ unoptimized database queries, the UI was outdated and non-responsive, and deleting any reference data item (such as a delivery location) silently corrupted historical records across the entire user base.

The client had lost confidence in the previous vendor and needed a partner who could execute a ground-up rebuild without disrupting active brokerage operations serving dozens of grain producers.

We executed a complete platform modernization over 8 weeks, replacing the legacy .NET monolith with a modern, cloud-native architecture:

Backend: Python/FastAPI with async processing, SQLAlchemy ORM, Alembic migrations, and comprehensive role-based access control (Admin, Manager, Client). The API grew to 55+ endpoints covering full CRUD for all domain entities.

Frontend: React with TypeScript, Tailwind CSS, mobile-responsive design, light/dark mode toggle, and progressive rendering for sub-second perceived load times. 21 fully functional pages were delivered.

Database: PostgreSQL (Azure Flexible Server) with enforced foreign key relationships, soft-delete logic to prevent data corruption, and schema separation for future multi-product support.

We adopted an aggressive sprint cadence: authentication and core APIs in Week 1, CRUD and dashboard KPIs by Week 2, options tracking and marketing plan formulas by Week 3, and PDF reports plus Azure deployment by Week 4. The client received working staging links with demo accounts from Day 5, enabling real-time feedback loops throughout the build.