#ktor javalin
#http4k are Kotlin-driven microframeworks if you need a small web server, API, REST, etc. They are mostly adhering to
https://12factor.net/ though might need some discipline in using. Spring is indeed an ultimate hammer, but it’s heavy, starts slow, and not as performant at scale as others. See
https://www.techempower.com/benchmarks/previews/round15/ for some benchmarks.