Labels

A label represents a shipping label purchased for a specific shipment. Labels include a tracking number, barcode, and the formatted label image ready for printing.

Creating a label

curl -X POST https://api.flexops.io/v1/labels \
  -H "X-API-Key: your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "carrier": "usps",
    "service": "priority",
    "from": {
      "name": "Warehouse A",
      "street1": "100 Shipping Lane",
      "city": "Denver",
      "state": "CO",
      "zip": "80202",
      "country": "US"
    },
    "to": {
      "name": "Jane Doe",
      "street1": "456 Oak Ave",
      "city": "Portland",
      "state": "OR",
      "zip": "97201",
      "country": "US"
    },
    "parcel": {
      "weightOz": 16,
      "lengthIn": 10,
      "widthIn": 8,
      "heightIn": 4
    }
  }'

Label response

{
  "id": "lbl_abc123",
  "trackingNumber": "9400111899223456789012",
  "carrier": "usps",
  "service": "priority",
  "labelUrl": "https://api.flexops.io/v1/labels/lbl_abc123/download",
  "labelFormat": "pdf",
  "rate": {
    "amount": 8.95,
    "currency": "USD"
  },
  "status": "created",
  "createdAt": "2026-03-10T12:00:00Z"
}

Label formats

Format	Description
pdf	Standard 4x6" PDF (default)
png	4x6" PNG image
zpl	Zebra Printer Language (thermal printers)

Specify the format with ?format=zpl when downloading.

Cancelling a label

Labels can be cancelled within the carrier's void window (typically 24 hours for domestic, varies for international):

curl -X POST https://api.flexops.io/v1/labels/lbl_abc123/cancel \
  -H "X-API-Key: your-api-key"