send multidimensional array in angularjs $http POST api call

I want to send multidimensional array in angularjs. The request is sending from angularjs UI to Laravel API side, In API side I need the input as

array:3 [
      0 => array:3 [
        "title" => "name1"
        "type" => "type1"
        "rate" => 11
      ]
      1 => array:3 [
        "title" => "name2"
        "type" => "type2"
        "rate" => 31
      ]
      2 => array:3 [
        "title" => "name3"
        "type" => "type3"
        "rate" => 13.333
      ]
    ]

But I not getting so. The static data I am trying to send from angular is

var values = [
              {
                  "title" => "name1"
                  "type" => "type1"
                  "rate" => 11
              },
              {
                  "title": "Make an offer Rate",
                  "type": "make_offer_rate",
                  "rate": 30
              },
              {
                  "title": "Test price",
                  "type": "test_rate",
                  "rate": 100
              }
          ];

        $http({
                method: 'POST',
                url: urls.api_url_serv+'rate?token='+token,
                transformRequest: transformRequestAsFormPost,
                data: {
                     rates:JSON.stringify(values),
                },
                withCredentials: false,
                headers: {
                     'Accept': 'application/json',
                     'Content-Type': "application/x-www-form-urlencoded"
                };

Its getting as string in API side When I tried to dd() the Response was
"[{"title":"name1","type":"type1","rate":45},{"title":"name2","type":"type2","rate":30},{"title":"name3","type":"type3","rate":100}]"
I need to handle it from UI side since the API section is not done by me

via Chebli Mohamed