An api gateway, acts as oauth2 authorization server, api throttling, api proxy.
POST https://api-gateway.herokuapp.com/oauth/token HTTP/1.1
Accept: */*
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Host: api-gateway.herokuapp.com
grant_type=password&client_id=123&client_secret=secret&username=bob&password=secret&scope=demo