The memory consumption of a "hello, world" quarkus JAX-RS application is comparable to "empty" Tomcat or Jetty (see: Memory (RAM) Consumption of: Tomcat, Jetty and Quarkus).
However: how big is quarkus application relying on MicroProfile dependencies like e.g. JSON-B, JAX-RS, CDI, Metrics, Config, OpenAPI
and Health? ...and what is the impact of
-Xmx18m on Java's / Quarkus memory consumption?:
In this screencast I created a Quarkus application from scratch and compared the memory footprint with "empty" Jetty: