Using Sendgrid in your own app is easy now.
Simply reference email in your module:
var app = angular.module('myapp', ['email']);
and then $email in your controller:
function MyController($scope, $email, $http, $log)
Set your API user and Key Variables (I'm hoping this will change in the future):
var api_user = "";
var api_key = "";
Finally send an email:
$email.$send(api_user, api_key, to, name, "Test", "This Please click on this link to confirm your email address: \n\n someURL/" + "\n\n", "somename@somesite.com");