I'm a big fan of using node for an intermediary web stack. It really plays well for handling your web layer with the tools available as well as handling builds

I'm a big fan of using node for an intermediary web stack. It really plays well for handling your web layer with the tools available as well as handling builds with grunt and friends. I think the real potential comes in when you blend it with a heavy lifting API written in go or on the JVM. Easy web layer that's agnostic to whatever heavy processing language should you decide to do. Obviously there's a bit of complexity that comes with this, but if you need to scale up it's right there. Even then, node is pretty powerful on its own, where you might not need a crazy backend.