Me too :). Mostly engineering systems for programming Edge Devices used in factory automation. The user usually runs windows, the edge device linux.

What kind of hardware/OS are you usually writing code for?

We write mostly Java, some Kotlin, targeting the JVM.

Most commonly our software runs on premises on server-class hardware (or what passes for server-class depending on the industry...), sometimes hosted in the cloud, sometimes on "edge" hardware (think Raspberry Pi class power/spec wise).

One component of the software actually is a web frontend (and a Jetty backend) to go with it, but it's not your typical "web-app" and it's not SaaS. But there's much more to it than that.