USPS - Rates First Class

{
  "carrier": "USPS",
  "action": "getallrates",
  "params": {
    "username": "YOUR_USERNAME",
    "service": "First Class",
    "packages": [
      {
        "weight": 0.3,
        "first_class_mail_type": "PARCEL"
      }
    ],
    "ship_code": "59759",
    "to_code": "90210"
  }
}

<?php
$rs = new RocketShipIt;
$response = $rs->request(
array (
  'carrier' => 'USPS',
  'action' => 'getallrates',
  'params' => 
  array (
    'username' => 'YOUR_USERNAME',
    'service' => 'First Class',
    'packages' => 
    array (
      0 => 
      array (
        'weight' => 0.3,
        'first_class_mail_type' => 'PARCEL',
      ),
    ),
    'ship_code' => '59759',
    'to_code' => '90210',
  ),
)
);

rs.request(
  {'action': 'getallrates',
 'carrier': 'USPS',
 'params': {'packages': [{'first_class_mail_type': 'PARCEL', 'weight': 0.3}],
            'service': 'First Class',
            'ship_code': '59759',
            'to_code': '90210',
            'username': 'YOUR_USERNAME'}}

)

rs.request(
  {"carrier"=>"USPS",
 "action"=>"getallrates",
 "params"=>
  {"username"=>"YOUR_USERNAME",
   "service"=>"First Class",
   "packages"=>[{"weight"=>0.3, "first_class_mail_type"=>"PARCEL"}],
   "ship_code"=>"59759",
   "to_code"=>"90210"}}

)

rocketshipit.request(
  {
  "carrier": "USPS",
  "action": "getallrates",
  "params": {
    "username": "YOUR_USERNAME",
    "service": "First Class",
    "packages": [
      {
        "weight": 0.3,
        "first_class_mail_type": "PARCEL"
      }
    ],
    "ship_code": "59759",
    "to_code": "90210"
  }
}
)