What's "thread-per-request" to you exactly? By default, Spring Boot uses an integrated Tomcat in standalone mode. That Tomcat is configured to use a worker thr

What's "thread-per-request" to you exactly? By default, Spring Boot uses an integrated Tomcat in standalone mode. That Tomcat is configured to use a worker threadpool with a default size of 200. In addition to that you can make Controller methods "asynchronous" (as in free the worker thread as soon as possible) by simply wrapping the methods content in a Callable<T>, which amounts to wrapping it in a lambda method. Calling methods asynchronously is trivial as well, you just need to annotate them with @Async and wrap your result in an AsyncResult<T>. If you follow the reactive/async/callback/functional cargo cult you can use the brand-new, already usable Spring 5.x spring-webflux. As they describe it: "fully reactive and non-blocking. It is suitable for event-loop style processing with a small number of threads"