Webhook

shipments.cancelled

A shipment was cancelled by Whatnot support. Requires read:shipments.

Headers

webhook-id
Type: stringFormat: uuid
required

Unique ID of the event. Retries of a delivery send the same ID, so use it to deduplicate.
webhook-timestamp
Type: integerFormat: int64
required

When this delivery attempt was sent, as a Unix timestamp in seconds. Each retry sends a new timestamp.
webhook-signature
Type: string
required

Space-separated signatures, each v1, followed by the base64 HMAC-SHA256 of {webhook-id}.{webhook-timestamp}.{body}, keyed with your webhook secret.

Body·ShipmentCancelledWebhookBody

required

application/json

data
Type: Shipment
required

The event's data. Its shape depends on the topic.

Properties: 18
seller_id
Type: string
required

The ID of the seller the event belongs to.
timestamp
Type: stringFormat: date-time
required

When the event happened, in ISO 8601. Stable across retries; the webhook-timestamp header is when each attempt was sent.
type
const:
shipments.cancelled
required

The webhook topic.
version
const:
v2
required

The payload version.

Responses

200

Acknowledge delivery. Any 2XX status counts.
default

Fail delivery. Non-2XX statuses and timeouts are retried.

postshipments.cancelled

{
  "type": "shipments.cancelled",
  "timestamp": "2026-10-20T16:00:00.123Z",
  "data": {
    "created_at": "2026-09-21T12:00:00.000Z",
    "dimensions": {
      "height": 1,
      "length": 6,
      "unit": "inch",
      "width": 4
    },
    "documents": {
      "bundled_url": "https://example.com/documents.pdf",
      "label_url": "https://example.com/label.pdf"
    },
    "dropoff_due": "2026-09-23T07:00:00.000Z",
    "fulfillment_method": "shipping",
    "hazardous_material": "not_hazardous",
    "id": "12345",
    "insurance": {
      "amount": {
        "amount": "25.00",
        "currency": "USD"
      },
      "contents": "Trading cards"
    },
    "recipient": {
      "display_name": "Card Collector",
      "id": "6789",
      "username": "cardcollector"
    },
    "required_actions": [],
    "seller_paid_shipping_cost": {
      "amount": "5.99",
      "currency": "USD"
    },
    "signature_required": false,
    "status": "label_generated",
    "tracking": {
      "carrier": "usps",
      "service": "usps_ground_advantage",
      "tracking_code": "9400111899223100012345"
    },
    "updated_at": "2026-09-21T13:00:00.000Z",
    "url": "https://www.whatnot.com/dashboard/shipments/U2hpcG1lbnROb2RlOjUxMjU0MTM5Mw==",
    "weight": {
      "unit": "ounce",
      "value": 4
    }
  },
  "version": "v2",
  "seller_id": "1234567"
}

No Body

Acknowledge delivery. Any 2XX status counts.

shipments.items.removed

shipments.replaced