gistfile1.txt

<?php

$request = new HttpRequest();
$request->setUrl('http://54.191.139.107/api/v2/shipping_rates');
$request->setMethod(HTTP_METH_POST);

$request->setHeaders(array(
  'postman-token' => '1bbbe833-ee3b-4075-a024-ebe4f8bae2de',
  'cache-control' => 'no-cache',
  'content-type' => 'application/json'
));

$request->setBody('{
           "rate": {
               "origin": {
                   "country": "MX",
                   "postal_code": "64898",
                   "province": "NL",
                   "city": "Monterrey",
                   "name": null,
                   "address1": "hda. cataluña 4941",
                   "address2": "residencial la hacienda",
                   "address3": null,
                   "phone": null,
                   "fax": null,
                   "address_type": null,
                   "company_name": null
               },
               "destination": {
                   "country": "MX",
                   "postal_code": "66231",
                   "province": "NL",
                   "city": "San Pedro Garza García",
                   "name": "Jason Normore",
                   "address1": "Rio guadalquivir 422A",
                   "address2": "del valle",
                   "address3": null,
                   "phone": "7097433959",
                   "fax": null,
                   "address_type": null,
                   "company_name": null
               },
               "items": [
                   {
                       "name": "My Product 3",
                       "sku": null,
                       "quantity": 1,
                       "grams": 1000,
                       "price": 2000,
                       "vendor": "TestVendor",
                       "requires_shipping": true,
                       "taxable": true,
                       "fulfillment_service": "manual"
                   }
               ],
               "currency": "MXN"
           }
        }');

try {
  $response = $request->send();

  echo $response->getBody();
} catch (HttpException $ex) {
  echo $ex;
}