Kestrel web server in ASP.NET Core | Microsoft Learn

Kestrel is a cross-platform web server for ASP.NET Core. Kestrel is the web server that’s included and enabled by default in ASP.NET Core project templates. Kestrel supports the following scenarios: HTTPS; HTTP/2 (except on macOS†) Opaque upgrade used to enable WebSockets; Unix sockets for high performance behind Nginx

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/servers/kestrel?view=aspnetcore-9.0