A chart-data archive migrated off SQL Server 7, Classic ASP and Visual FoxPro to Azure SQL and Blazor on App Service, with the FoxPro tools kept running against the new database until replaced.
What was wrong
A music-chart publisher's entire archive lived on SQL Server 7, a Classic ASP application and Visual FoxPro book-generation tools, a stack nobody could hire for on hardware that would not last. The business ran on it every day, so there was no window to take it down and replace it.
What I built
Restored the old backups into Azure SQL, rebuilt the legacy application for the cloud with user and admin security on Entra ID, and kept the FoxPro book-generation tools running against the new database throughout. Built a data validator that pulls chart data from an outside scraped source, transforms it to the publisher's own conventions, and shows an editor exactly what will be written before anything goes to production. Used an LLM to reverse-engineer legacy records with a confidence score on each and statistical sampling to verify rather than trust.
What happened in production
Live on Azure. Along the way the validator found that weeks-at-peak figures had been silently inflated for years, a data error nobody knew they had.