How do I create shipments and print labels from an API?

To create shipments and print labels from an API, the general flow is:

1. Create a shipment / parcel / order
2. Rate it (optional but common)
3. Buy / purchase the label
4. Download or print the label
5. Track the shipment

The exact endpoints vary by carrier or shipping platform, but the pattern is usually the same.

Typical API flow

1) Authenticate

Most shipping APIs require an API key or OAuth token.

Example:

Authorization: Bearer YOUR_API_TOKEN
Content-Type: application/json

---

2) Create a shipment request

You send details like:

• Sender address
• Recipient address
• Package weight and dimensions
• Service level
• Insurance / customs info if needed

Example JSON:

{
  "ship_to": {
    "name": "Jane Doe",
    "address1": "123 Main St",
    "city": "Austin",
    "state": "TX",
    "postal_code": "78701",
    "country": "US"
  },
  "ship_from": {
    "name": "My Warehouse",
    "address1": "500 Warehouse Rd",
    "city": "Dallas",
    "state": "TX",
    "postal_code": "75201",
    "country": "US"
  },
  "package": {
    "weight": 2.5,
    "weight_unit": "lb",
    "length": 10,
    "width": 6,
    "height": 4,
    "dimension_unit": "in"
  },
  "service": "ground"
}

---

3) Get rates

The API returns available shipping options and prices.

Example response:

{
  "rates": [
    {
      "carrier": "UPS",
      "service": "Ground",
      "amount": "12.45",
      "currency": "USD",
      "estimated_delivery": "2026-10-08"
    },
    {
      "carrier": "FedEx",
      "service": "Home Delivery",
      "amount": "13.10",
      "currency": "USD",
      "estimated_delivery": "2026-10-07"
    }
  ]
}

---

4) Purchase the label

Once you choose a rate, submit a “buy label” or “create shipment” request.
The response usually includes:

• Shipment ID
• Tracking number
• Label URL or label binary/base64
• Carrier details

Example response:

{
  "shipment_id": "shp_12345",
  "tracking_number": "1Z999AA10123456784",
  "label_url": "https://api.example.com/labels/label_123.pdf"
}

---

5) Print the label

Depending on the API, labels may be returned as:

• PDF URL — download and print
• Base64 PDF — decode and print
• ZPL/PNG — send directly to printer or render first

If it’s a PDF URL:

curl -o label.pdf "https://api.example.com/labels/label_123.pdf"

If it’s base64:

import base64

label_b64 = response["label"]
with open("label.pdf", "wb") as f:
    f.write(base64.b64decode(label_b64))

---

Example using a generic REST API in Python

import requests

API_TOKEN = "YOUR_API_TOKEN"
BASE_URL = "https://api.example.com"

headers = {
    "Authorization": f"Bearer {API_TOKEN}",
    "Content-Type": "application/json"
}

shipment_data = {
    "ship_to": {
        "name": "Jane Doe",
        "address1": "123 Main St",
        "city": "Austin",
        "state": "TX",
        "postal_code": "78701",
        "country": "US"
    },
    "ship_from": {
        "name": "My Warehouse",
        "address1": "500 Warehouse Rd",
        "city": "Dallas",
        "state": "TX",
        "postal_code": "75201",
        "country": "US"
    },
    "package": {
        "weight": 2.5,
        "weight_unit": "lb",
        "length": 10,
        "width": 6,
        "height": 4,
        "dimension_unit": "in"
    },
    "service": "ground"
}

# Create shipment
resp = requests.post(f"{BASE_URL}/shipments", json=shipment_data, headers=headers)
resp.raise_for_status()
data = resp.json()

print("Shipment created:", data)
print("Tracking number:", data.get("tracking_number"))
print("Label URL:", data.get("label_url"))

---

Printing the label

If the API gives you a PDF:

• Open it and print from your computer/server
• Or send it to a label printer
• For thermal printers, many APIs support ZPL format

Example label formats:

• PDF: good for regular printers
• ZPL: best for Zebra thermal printers
• PNG: sometimes supported for preview

---

Important things to check

• Label size: 4x6 is common for shipping labels
• Printer compatibility: PDF vs ZPL
• International shipments: customs forms required
• Address validation: many APIs provide it
• Void/cancel endpoint: useful if you create a label by mistake

---

If you tell me the shipping provider

If you want, I can give you exact code for:

• Shippo
• EasyPost
• UPS
• FedEx
• DHL
• USPS
• or your own custom API

If you share the provider and language you’re using, I can write a working example.