It can't be run locally. Some of the feature we've built would be really difficult if not impossible to run offline. That said, maybe someday a paired down version for local use would make sense.
So it can't be used to replace the built-in REPL and play with your unpublished modules? That's a shame; the built-in node REPL has never been pleasant to work with. I would definitely pay money for a local version of this.
