Regarding the venerable Tomcat, they [somewhat] recently added support for Unix domain sockets. * https://github.com/apache/tomcat/pull/402 https://github.com/

Regarding the venerable Tomcat, they [somewhat] recently added support for Unix domain sockets. * https://github.com/apache/tomcat/pull/402 https://github.com/apache/tomcat/pull/402 * https://github.com/apache/tomcat/pull/532 https://github.com/apache/tomcat/pull/532 We fronted the server with haproxy LTS. Our initial testing showed roughly and order of magnitude [10x] increase in the number of requests the server could handle. It's not completely plug-and-play; we still had a write a custom valve to set the request remote ip address and some other TCPish stuff, but nevertheless the capacity far outstripped our need for the technology.