If you see lots of 401 responses on requests other than GET requests, it's likely because elm-rails doesn't know about the CSRF token Rails includes in the header in a <meta> tag. For a drop-in fix, include csrf-xhr on all pages which use elm-rails. (Alternatively, you can pass the token into your Elm program through a flag, store it in your Model, and add the header to all requests manually. Needless to say, including csrf-xhr on the page is much easier!)
