Another update, thanks to @mwmiller there is an online, live version of Erlang-RED available.
It's read-only and basically only good for going to the testing tab, pressing refresh flows and then pressing test all.
Flows can be loaded by double clicking on them in the testing panel. Deploying them does say that they got saved but that's a cunning lie.
This is very much beta and buggy, if it doesn't work then its intention was to work but it didn't quite fulfil those good intentions.
And yes: this is really Erlang, there is no NodeJS involved.