UPDATE (Sept 23, 2013): 3Scale has published an official “Flash Tutorial” to my approach for running their proxy on Heroku.
I have been playing around with 3Scale’s API Proxy for a side project. 3Scale provides a wrapper around your API, and supports monetizing, authenticating, throttling, and plenty of other “API stuff” you might need.
Their proxy is simply a set of Nginx config files, but I didn’t want to start a new Micro AWS instance just to run it. So, I decided to try running Nginx on Heroku. I found some other folks who had already done the hard work, and cobbled together a working example. Now I’ve got an API Proxy running in Heroku’s free usage tier. Cool!