Freeware library to create Excel files
https://github.com/dotnetcore/NPOI
ASP.NET Core
A Few Great Ways to Consume RESTful API in C#
https://www.codeproject.com/Articles/1190592/A-Few-Great-Ways-to-Consume-RESTful-API-in-Csharp
Build a .NET Core and SQL Database web app in Azure App Service on Linux
https://docs.microsoft.com/en-us/azure/app-service/containers/tutorial-dotnetcore-sqldb-app