Request and response with Angular $post and PHP Codeigniter
If you want to send as form encoded data you need to serialize the whole data object with $.param()
Change:
data: {user: $.param($scope.user)},To
data: $.param(angular.copy({user: $scope.user})),Or use $httpParamSerializerJQLike
If you use defaults of $http would just be
$http.post( '/registration',$scope.user).then(...And in php
$data = json_decode(file_get_contents('php://input'));