There are many examples of integrating htmx with server-side frameworks available on GitHub. Generally speaking, most server-side frameworks are already pretty well set up to integrate with htmx - after all, most of them were rendering HTML long before JSON became popular.
Different frameworks and platforms may offer alternative systems for installing htmx - for example, in the Java / JVM ecosystem, WebJars allows the use of npm packages with popular Java build tools such as Maven and Gradle.
These examples may make it a bit easier to get started using htmx with your platform of choice.
https://github.com/Rattlyy/htmx-ktor
https://github.com/corlaez/todo-hda-kt