Use http4s with Google Cloud Functions. It's a simple wrapper around the http4s-dsl.
You'll find the artifacts in maven central.
libraryDependencies += "com.github.ingarabr" % "http4s-cloud-functions" % "<version>"
Extend the Http4sCloudFunctionIOApp
trait and implement the routes
function. You find a complete example under docs/example-usage.md.