Sorry, your definition of &quot;concurrent&quot; is all over the place.<p>Ruby doesn&#x27;t have &quot;built in concurrency&quot;? Ruby has fully native threads; it just has the GIL that blocks for IO (but you could use jRuby). It gives you several options for message passing. You also have the extremely under-rated dRuby system. Not to mention the whole EventMachine world.<p>Node is &quot;close&quot; to concurrent? It&#x27;s god damn <i>single-threaded</i>! At the very least it&#x27;s possible to spawn multiple processes and communicate over a Unix socket, good luck doing something like that with PHP. What does socket.io have to do with anything?<p>Sorry man, I&#x27;m hearing a lot of cargo cult opinions and precious little data to back it up.