Hi Travis, frankly I consider the built in REST service unusable and full of head scratchers. If I recall, onError is not called with the built in REST framework, and/or its not easy to get a standard stack trace dump. Maybe others have built a robust app with it, but I gave up and I'd recommend
http://taffy.io/ or framework-one
https://github.com/framework-one/fw1 to construct your REST application.