- express, koa and hapi are http server frameworks, that&#x27;s just a very different thing<p>- strongloop offers pub&#x2F;sub capabilities as well, but is also first and foremost a service for rest apis<p>- socket.io is a transport layer with a low level concept of &quot;rooms&quot; to establish pub&#x2F;sub behaviour. Deepstream and Socket.io actually both use engine.io for browser communication