Vaadin’s greatest capability is in being able to write the UI in Java. Can this alone be separated out and made available, without it being hardwired with servlet container? If today someone wants to consume REST api in Vaadin (especially for NIO based end to end framework), they essentially need 2 JVMs running. This introduces extra complexity into the system - serialization/deserialization cost, process maintenance, more RAM needed, authentication etc. So, if, the ability to create a component and spitting out the rendering, is refactored out, it will benefit a lot in implementing NIO based high performance backends without needing to have separate JVMs. There are adapters present in the community today e.g. there is one for Vert.x and Vaadin, but likely it has pretty high maintenance cost and may not have been tested in production.