Size and Weight


Accuracy is Key

Strive to be as accurate as possible when shipping! The more accurate your information is, the better the rate quote you will receive from the carriers.

Additionally, if the shipping information is incorrect, most carriers will follow up with a charge to make up the difference. This may result in your package being held until the extra delivery cost is paid by you or the recipient.

The Basics


Weight inside of a shipment's packages object is required.

Property Description
unit enumerated string, required
ounce, pound, gram, kilogram
value decimal, required
Weight in the unit specified.


Optionally, you can specify the dimensions of each package in the shipment.

Property Description
unit enumerated string, required
inch, centimeter
length decimal, required
Length in the unit specified.
width decimal, required Width in the unit specified.
height decimal, required Height in the unit specified.

Add the objects directly into the shipment object. Use this same format to get shipping rates as well.


POST /v1/labels/

This example shows how to ship a package with a shipping weight of 9.6 ounces, and box dimensions of 12.0 x 7.1 x 6.0 inches.

POST /v1/labels HTTP/1.1
Content-Type: application/json

  "shipment": {
    "packages": [
        "weight": {
          "value": 9.6,
          "unit": "ounce"
        "dimensions": {
          "unit": "inch",
          "length": 12.0,
          "width": 7.1,
          "height": 6.0
    "service_code": "usps_priority_mail",
    "ship_to": {
      "name": "Amanda Miller",
      "phone": "555-555-5555",
      "address_line1": "525 S Winchester Blvd",
      "city_locality": "San Jose",
      "state_province": "CA",
      "postal_code": "95128",
      "country_code": "US",
      "address_residential_indicator": "yes"
    "ship_from": {
      "company_name": "Example Corp.",
      "name": "John Doe",
      "phone": "111-111-1111",
      "address_line1": "4009 Marathon Blvd",
      "address_line2": "Suite 300",
      "city_locality": "Austin",
      "state_province": "TX",
      "postal_code": "78756",
      "country_code": "US",
      "address_residential_indicator": "no"
  "label_id": "se-test-202923521",
  "status": "processing",
  "shipment_id": "se-202923521",
  "ship_date": "2019-07-25T05:00:00.000Z",
  "created_at": "2019-07-25T15:24:46.657Z",
  "shipment_cost": {
    "currency": "usd",
    "amount": 0.0
  "insurance_cost": {
    "currency": "usd",
    "amount": 0.0
  "tracking_number": "9999999999999",
  "is_return_label": false,
  "is_international": false,
  "batch_id": "",
  "carrier_id": "se-123890",
  "service_code": "usps_priority_mail",
  "package_code": "package",
  "voided": false,
  "voided_at": null,
  "label_format": "pdf",
  "label_layout": "4x6",
  "trackable": true,
  "carrier_code": "stamps_com",
  "tracking_status": "unknown",
  "label_download": {
    "pdf": "",
    "png": "",
    "zpl": "",
    "href": ""
  "form_download": null,
  "insurance_claim": null

Step 2: Ship It!

You can now print your label and ship! Find your label by going to label_download.href.