Not the view name but rather what ‘higher up’ in the callstack is calling your render function. In a base error rendrerer there’s very little above it and I’m not sure if the content-type requested by the client is followed or not (since it’s an error and the body shouldn’t be used for data anyway).
You can always return the stacktrace in that function and see what it’s going through, there might be an option? 
Edit: Googled a bit and the Phoenix View documentation shows rendering JSON from a map in an example. So it should work.
That’s for rendering from controllers, not errors though, I’m unsure about error handling.
