I suggest returning 404 Not Found instead of 422 Unprocessable Entity on failed GETs: https://jsonbin.io/b/2342342 as well as Content-Type: application/json instead of current text/html.

"Entity" in "Unprocessable Entity" refers to request body and for GETs there is no request body: http://www.restpatterns.org/HTTP_Status_Codes/422_-_Unproces...