[damianh]

Since you mention Kestrel I'll assume .NET so I suggest you take a look at yarp. It's fully programmable and "plugins" are just small pieces of middleware, a lot of which is available as a nuget package.

(I'm the author of ProxyKit that predated yarp)

[jddj]

Oh, very nice. We do use YARP actually on some of those other projects, and I was going to mention it. It's great.

This particular (small, internal) project was in Go, so I wanted to use the opportunity to forego any extra runtimes and just used nginx.