Since I'm developing on localhost. I therefore need a way to proxy the legacy app to make it also appear on localhost (or at least the same as something hosted locally).
To complicate things just a little, due to decree by the firewall gods which I cannot influence, I cannot access access the publicly available legacy app (which is hosted in the same building), from my development network specifically, unless I ssh tunnel to some random exit point on the public internet and configure chrome to access the legacy app's domain via the resulting local socks proxy. In the production environment, this whole problem won't exist, but for now I've got to work with what I have.
This sounds like something solvable with a certain local nginx configuration, which would present both my locally running web app and the proxied legacy app as the same host, though I'm not sure what this would be called.
Are there other, perhaps simpler solutions I should consider?