User36583972 posted
Hi samolppwt,
ASP.NET Web API is a framework that makes it easy to build HTTP services that reach a broad range of clients, including browsers and mobile devices. ASP.NET Web API is an ideal platform for building RESTful applications on the .NET Framework.
Learn About ASP.NET Web API:
http://www.asp.net/web-api/overview/getting-started-with-aspnet-web-api
i want to use this as a middleware/businesslogic layer which in turn consumed by a web part
You can create a Web API and call stored procs in sql server.
MVC, AngularJS CRUD Using WEB API 2 With Stored Procedure:
http://www.c-sharpcorner.com/uploadfile/asmabegam/mvc-angularjs-crud-using-web-api-2-with-stored-procedure/
which in turn consumed by a web part within SharePoint
The following tutorial for your reference.
A Sample SharePoint App That Calls A Custom Web API:
https://blogs.msdn.microsoft.com/kaevans/2015/03/25/a-sample-sharepoint-app-that-calls-a-custom-web-api/
If you have some questions about SharePoint, please go to
SharePoint forum for suitable help.
Best Regards,
Yohann Lu