I have a nearly-finished invoicing and customer portal that was built in Python/PostgreSQL; it now has to live on our real stack—C# and SQL Server—while keeping the existing HOMER-based UI untouched. Your first task will be to study the current codebase front-to-back, with special attention on the invoicing module. Once you grasp how the Python version stitches together its recurring billing, customizable invoice templates and tax calculations, I need you to lay out a clean C# architecture, migrate the database schema and data to SQL Server, then drive the project to production. You’ll have a functional specification, invoice samples and all spreadsheet source data at hand, plus the working (98 % complete) Python solution as a reference. I expect disciplined, agentic development: using Git branches, Codex-style AI code reviews and automated testing so progress stays transparent. Key deliverables: • C# solution reproducing every current feature, compiled against .NET 6+ • SQL Server schema + data migration scripts with roll-backs • Fully working invoicing module (recurring billing, template customisation, tax logic) verified by unit and integration tests • Customer portal wired to the same HOMER HTML/CSS, pixel-perfect to the existing UI • Deployment pipeline (Azure DevOps or GitHub Actions) pushing to a staging environment Acceptance criteria will be met when the migrated application generates identical invoices to the Python version, passes automated tests, and runs end-to-end on SQL Server without visible UI changes. If C#, SQL Server, business-grade billing logic and AI-assisted workflows are your daily bread, let’s get this portal over the finish line.