ASP.NET is an open source web framework, created by Microsoft, for building modern web apps and services with . NET. ASP.NET is cross platform and runs on Linux, Windows, macOS, and Docker.
Is ASP.NET Dead ?
Should you learn C# and ASP.Net for 2020 (Video)
Until the middle of 2019, ASP.NET has been being used as a server-side framework for web app development. But now, you can build SPA web apps with Blazor instead of using some client-side JS based framework like Angular or library like React. NET definitely worth learning in 2020 because it is going to be the future.