Order lifecycle implementation

This guide provides the technical API reference and payload schemas for pushing full order status updates, fulfillment events, and adjustments to Google using webhooks for version 2026-04-08 of the Universal Commerce Protocol (UCP).

Before building your endpoints, ensure you have reviewed the Order lifecycle overview for the high-level concepts, mandatory events, and webhook endpoint details.

Auth and request signing

Key changes in version 2026-04-08 include the introduction of new mandatory webhook headers and specific request signing procedures.

Required webhook headers

The following HTTP headers are mandatory for all webhook requests:

• Webhook-Id: A unique identifier for this specific webhook event. This ID should match the id of the primary event being sent (for example, the fulfillment event ID or adjustment event ID).
• Webhook-Timestamp: The timestamp indicating when the event occurred.

These headers replace the id and created_time fields previously expected in the order payload.

Note: Google uses this header to evaluate order freshness. An order update will be rejected if this timestamp is older than the latest recorded update.

Request signing

1. Compute SHA-256 digest of the raw request body and set Content-Digest header.
2. Select a signing key from signing_keys in your UCP profile.
3. Build signature base per RFC 9421.
   • See the spec for signed components
4. Set UCP-Agent, Signature-Input, and Signature headers.
   • UCP-Agent is a link to your UCP profile in the format profile="https://merchant.example.com/.well-known/ucp".
   • Signature-Input is a dictionary structured field describing the components contained within the signature, as well as the keyid used to sign, which must match the kid of your selected signing key from signing_keys in your UCP profile.
   • Signature header contains your signature base which is signed using your private key and then base64 encoded.

See the signing instructions on ucp.dev for more information.

Order created event

• Trigger: Immediately after the order is confirmed (status: processing).

Key changes in this version:

• The currency field is now required at the top level of the Order object.
• The type field within each object in the totals array is now an open string (for example, "subtotal", "tax", "fee", "total").
• The mandatory Webhook-Id header contains a unique identifier for the webhook event. Note that the id field in the payload containing the order confirmation ID is still required.
• The mandatory Webhook-Timestamp header provides the creation time, replacing the former created_time field in the payload.

Example: This example shows an order created after a buyer completes the checkout.

Required Headers:

• Webhook-Id: order_01
• Webhook-Timestamp: 2026-03-23T19:00:00Z

{
  "ucp": {
    "version": "2026-04-08",
    "capabilities": {
      "dev.ucp.shopping.order": [{"version": "2026-04-08"}]
    }
  },
  "id": "order_01",
  "checkout_id": "checkout_01",
  "currency": "USD",
   // Always include all line items, even for single-item checkouts. This ensures any add-ons, gifts, or separate charges are accounted for.
  "line_items": [
    {
      "id": "line_1",
      "item":
        {
          "id": "product_123",
          "title": "Running Shoes",
          "price": 10000
        },
      "quantity": { "total": 1, "fulfilled": 0 },
      "totals": [
        {"type": "subtotal", "display_text": null, "amount": 10000},
        {"type": "total", "display_text": null, "amount": 10000}
      ],
      // The status of a line item must match total and fulfilled quantities (e.g., total 1, fulfilled 0 -> status: processing).
      "status": "processing"
    }
  ],
  "totals": [
    {"type": "subtotal", "display_text": "Subtotal", "amount": 10000}, // Tax-inclusive markets: Set display_text to "Subtotal (including taxes)". Amount must include tax.
    {"type": "fee", "display_text": "Service Fee", "amount": 100},
    {"type": "tax", "display_text": "Tax", "amount": 800}, // Tax-inclusive markets: Omit this entry.
    {"type": "total", "display_text": "Total", "amount": 10900}
  ],
  "fulfillment": {
    "expectations": [
      {
        "id": "exp_1",
        "line_items": [{ "id": "line_1", "quantity": 1 }],
        "method_type": "shipping",
        "destination": {
          "first_name": "Alice",
          "last_name": "Example",
          "street_address": "123 Main St",
          "address_locality": "Austin",
          "address_region": "TX",
          "address_country": "US",
          "postal_code": "78701"
        },
        "description": "Arrives in 2-3 business days",  // Maximum length: 200 characters.
        "fulfillable_on": "now"
      }
    ]
  },
  "permalink_url": "https://merchant.example.com/orders/789"
}

Fulfillment events

These events are sent as part of the fulfillment.events array.

Note: When fulfillment events occur, the expectations object must be kept consistent with any updates. For example, if the events indicate that the order comprises two packages, expectations should also reflect this. Expectations don't need to be updated for adjustments (for example, cancellations).

Order shipped

When items in the order have been shipped. The tracking_number and tracking_url fields are required for shipped events, as these are required to group items on the "My orders" page accurately.

Order delivered

When items in the order have been delivered.

Example (shipped and delivered): This example shows an order update after the item has been shipped and then delivered.

Required Headers:

• Webhook-Id: fulfill_evt_2
• Webhook-Timestamp: 2026-02-10T14:00:00Z

{
  "ucp": {
    "version": "2026-04-08",
    "capabilities": {
      "dev.ucp.shopping.order": [{"version": "2026-04-08"}]
    }
  },
  "id": "order_01",
  "checkout_id": "checkout_01",
  "currency": "USD",
  "line_items": [
    {
      "id": "line_1",
      "item":
        {
          "id": "product_123",
          "title": "Running Shoes",
          "price": 10000
        },
      "quantity": { "total": 1, "fulfilled": 1 },
      "totals": [
        {"type": "subtotal", "amount": 10000},
        {"type": "total", "amount": 10000}
      ],
      "status": "fulfilled"
    }
  ],
  "totals": [
    {"type": "subtotal", "amount": 10000},
    {"type": "total", "amount": 10000}
  ],
  // Updated fulfillment details
  "fulfillment": {
    "events": [
      {
        "id": "fulfill_evt_1",
        "occurred_at": "2026-02-08T10:30:00Z",
        "type": "shipped",
        "line_items": [{ "id": "line_1", "quantity": 1 }],
        "tracking_number": "123456789",
        "tracking_url": "https://fedex.com/track/123456789",
        "carrier": "FedEx",
        "description": "Shipping departed from warehouse"
      },
      {
        "id": "fulfill_evt_2",
        "occurred_at": "2026-02-10T14:00:00Z",
        "type": "delivered",
        "line_items": [{ "id": "line_1", "quantity": 1 }],
        "tracking_number": "123456789",
        "tracking_url": "https://fedex.com/track/123456789",
        "carrier": "FedEx",
        "description": "Package delivered"
      }
    ],
    "expectations": [{ "...": "..." }]
  },
  "permalink_url": "https://merchant.example.com/orders/123"
}

Multi-item order examples

The following examples demonstrate how to structure updates for multi-item orders and split shipments. For rules on how package statuses are derived, see How package status is determined.

Multi-item order, same package delivery

This example shows an order update for a single package containing multiple items. All line items are grouped within a single shipped event sharing the same tracking number.

Required Headers:

• Webhook-Id: fulfill_evt_1
• Webhook-Timestamp: 2026-02-08T10:30:00Z

{
  "ucp": {
    "version": "2026-04-08",
    "capabilities": {
      "dev.ucp.shopping.order": [{"version": "2026-04-08"}]
    }
  },
  "id": "order_multi_01",
  "checkout_id": "checkout_multi_01",
  "currency": "USD",
  "line_items": [
    {
      "id": "line_1",
      "item": { "id": "product_1", "title": "Item 1", "price": 5000 },
      "quantity": { "total": 1, "fulfilled": 1 },
      "totals": [
        {"type": "subtotal", "display_text": null, "amount": 5000},
        {"type": "total", "display_text": null, "amount": 5000}
      ],
      "status": "fulfilled"
    },
    {
      "id": "line_2",
      "item": { "id": "product_2", "title": "Item 2", "price": 5000 },
      "quantity": { "total": 1, "fulfilled": 1 },
      "totals": [
        {"type": "subtotal", "display_text": null, "amount": 5000},
        {"type": "total", "display_text": null, "amount": 5000}
      ],
      "status": "fulfilled"
    }
  ],
  "totals": [
    {"type": "subtotal", "display_text": "Subtotal", "amount": 10000},
    {"type": "fee", "display_text": "Shipping", "amount": 500},
    {"type": "total", "display_text": "Total", "amount": 10500}
  ],
  "fulfillment": {
    "expectations": [
      {
        "id": "exp_1",
        "line_items": [
          { "id": "line_1", "quantity": 1 },
          { "id": "line_2", "quantity": 1 }
        ],
        "method_type": "shipping",
        "destination": {
          "first_name": "Alice",
          "last_name": "Example",
          "street_address": "123 Main St",
          "address_locality": "Austin",
          "address_region": "TX",
          "address_country": "US",
          "postal_code": "78701"
        },
        "description": "Standard Shipping",
        "fulfillable_on": "now"
      }
    ],
    "events": [
      {
        "id": "fulfill_evt_1",
        "occurred_at": "2026-02-08T10:30:00Z",
        "type": "shipped",
        "line_items": [
          { "id": "line_1", "quantity": 1 },
          { "id": "line_2", "quantity": 1 }
        ],
        "tracking_number": "123456789",
        "tracking_url": "https://fedex.com/track/123456789",
        "carrier": "FedEx",
        "description": "Both items shipped together"
      }
    ]
  },
  "permalink_url": "https://merchant.example.com/orders/456"
}

Multi-item order, split shipment

This example shows an order update for split shipments. There are multiple shipped events, each referencing the specific line_items within that respective package, with distinct tracking numbers. Since each package represents a distinct fulfillment commitment (for example, different speeds and costs from a multi-group checkout), the expectations are also split.

Required Headers:

• Webhook-Id: fulfill_evt_2
• Webhook-Timestamp: 2026-02-09T14:00:00Z

{
  "ucp": {
    "version": "2026-04-08",
    "capabilities": {
      "dev.ucp.shopping.order": [{"version": "2026-04-08"}]
    }
  },
  "id": "order_multi_02",
  "checkout_id": "checkout_multi_02",
  "currency": "USD",
  "line_items": [
    {
      "id": "line_1",
      "item": { "id": "product_1", "title": "Item 1", "price": 5000 },
      "quantity": { "total": 1, "fulfilled": 1 },
      "totals": [
        {"type": "subtotal", "display_text": null, "amount": 5000},
        {"type": "total", "display_text": null, "amount": 5000}
      ],
      "status": "fulfilled"
    },
    {
      "id": "line_2",
      "item": { "id": "product_2", "title": "Item 2", "price": 5000 },
      "quantity": { "total": 1, "fulfilled": 1 },
      "totals": [
        {"type": "subtotal", "display_text": null, "amount": 5000},
        {"type": "total", "display_text": null, "amount": 5000}
      ],
      "status": "fulfilled"
    }
  ],
  "totals": [
    {"type": "subtotal", "display_text": "Subtotal", "amount": 10000},
    {"type": "fee", "display_text": "Shipping", "amount": 1500},
    {"type": "total", "display_text": "Total", "amount": 11500}
  ],
  "fulfillment": {
    "expectations": [
      {
        "id": "exp_1",
        "line_items": [{ "id": "line_1", "quantity": 1 }],
        "method_type": "shipping",
        "destination": {
          "first_name": "Alice",
          "last_name": "Example",
          "street_address": "123 Main St",
          "address_locality": "Austin",
          "address_region": "TX",
          "address_country": "US",
          "postal_code": "78701"
        },
        "description": "Standard Shipping",
        "fulfillable_on": "now"
      },
      {
        "id": "exp_2",
        "line_items": [{ "id": "line_2", "quantity": 1 }],
        "method_type": "shipping",
        "destination": {
          "first_name": "Alice",
          "last_name": "Example",
          "street_address": "123 Main St",
          "address_locality": "Austin",
          "address_region": "TX",
          "address_country": "US",
          "postal_code": "78701"
        },
        "description": "Express Shipping",
        "fulfillable_on": "now"
      }
    ],
    "events": [
      {
        "id": "fulfill_evt_1",
        "occurred_at": "2026-02-08T10:30:00Z",
        "type": "shipped",
        "line_items": [{ "id": "line_1", "quantity": 1 }],
        "tracking_number": "PKG1_TRACKING",
        "tracking_url": "https://fedex.com/track/PKG1_TRACKING",
        "carrier": "FedEx",
        "description": "First item shipped in package 1"
      },
      {
        "id": "fulfill_evt_2",
        "occurred_at": "2026-02-09T14:00:00Z",
        "type": "shipped",
        "line_items": [{ "id": "line_2", "quantity": 1 }],
        "tracking_number": "PKG2_TRACKING",
        "tracking_url": "https://fedex.com/track/PKG2_TRACKING",
        "carrier": "FedEx",
        "description": "Second item shipped in package 2"
      }
    ]
  },
  "permalink_url": "https://merchant.example.com/orders/457"
}

Adjustment event examples

The following examples demonstrate how to structure updates for refunds, returns, and cancellations. For a list of supported events and their definitions, see Adjustment events in the Order lifecycle overview.

Order cancellation and refund

This example shows an order where the item was canceled and refunded shortly after the order was placed.

Key changes in this version in this example:

• Line items affected by a cancellation now use "status": "removed" in the main line_items array.
• When line_items.status is removed:
  • The line_items.quantity.total is set to 0.
  • The original quantity is stored in the new line_items.quantity.original field.

Required Headers:

• Webhook-Id: adj_refund_1
• Webhook-Timestamp: 2026-02-09T11:05:00Z

{
  "ucp": {
    "version": "2026-04-08",
    "capabilities": {
      "dev.ucp.shopping.order": [{"version": "2026-04-08"}]
    }
  },
  "id": "order_02",
  "checkout_id": "checkout_02",
  "currency": "USD",
  "line_items": [
    {
      "id": "line_2",
      "item": {
        "id": "product_456",
        "title": "Smart Watch",
        "price": 29900
      },
      "quantity": {
        "total": 0,  // Item removed from order total.
        "original": 1,  // Original quantity before removal.
        "fulfilled": 0 //  Item was not fulfilled before cancellation.
      },
      "totals": [
        {"type": "subtotal", "amount": 29900},
        {"type": "tax", "amount": 2400},
        {"type": "total", "amount": 32300}
      ],
      "status": "removed" // Item is cancelled, returned, or refunded.
    }
  ],
  "totals": [
    {"type": "subtotal", "amount": 29900},
    {"type": "tax", "amount": 2400},
    {"type": "total", "amount": 32300}
  ],
    // Fulfillment expectations should still be present even if cancelled early.
  "fulfillment": {
    "expectations": [
      {
        "id": "exp_1",
        "line_items": [{ "id": "line_2", "quantity": 1 }],
        "method_type": "shipping",
        "destination": {
          "first_name": "Bob",
          "last_name": "Consumer",
          "street_address": "456 Oak Ave",
          "address_locality": "Anytown",
          "address_region": "CA",
          "address_country": "US",
          "postal_code": "90210"
        },
        "description": "Standard Shipping",
        "fulfillable_on": "now"
      }
    ]
    // "events": [] // No fulfillment events occurred before cancellation.
    },
  "adjustments": [
    {
      "id": "adj_cancel_1",
      "type": "cancellation",
      "description": "Customer changed mind",
      "line_items": [{ "id": "line_2", "quantity": -1 }],
      "occurred_at": "2026-02-09T11:00:00Z",
      "status": "completed"
    },
    {
      "id": "adj_refund_1",
      "type": "refund",
      "description": "Refund for cancelled item",
      "line_items": [{ "id": "line_2", "quantity": -1 }],
      "totals": [
        {"type": "subtotal", "display_text": "Subtotal", "amount": -29900}, // Negative amounts indicate money returned to the buyer. Tax-inclusive markets: Set display_text to "Subtotal (including taxes)". Amount must include tax.
        {"type": "tax", "amount": -2400}, // Tax-inclusive markets: Omit this entry.
        {"type": "total", "display_text": "Total", "amount": -32300}
      ],
      "occurred_at": "2026-02-09T11:05:00Z",
      "status": "completed"
    }
  ],
  "permalink_url": "https://merchant.example.com/orders/12345"
}

Order return and refund

This example shows an order where the item was shipped, delivered, and then returned and refunded.

Key changes in this version in this example:

• Line items affected by a return now use "status": "removed" in the main line_items array.
• When line_items.status is removed:
  • The line_items.quantity.total is set to 0.
  • The original quantity is stored in the new line_items.quantity.original field.
• In adjustments of type return, the line_items.quantity field within the adjustment uses a negative value (for example, -1) to indicate items being taken back.

Required Headers:

• Webhook-Id: adj_refund_2
• Webhook-Timestamp: 2026-02-10T10:00:00Z

{
  "ucp": {
    "version": "2026-04-08",
    "capabilities": {
      "dev.ucp.shopping.order": [{"version": "2026-04-08"}]
    }
  },
  "id": "order_03",
  "checkout_id": "checkout_03",
  "currency": "USD",
  "line_items": [
    {
      "id": "line_3",
      "item": {
        "id": "product_789",
        "title": "Wireless Earbuds",
        "price": 14900
      },
      "quantity": {
        "total": 0,  // Item removed from order total.
        "original": 1,  // Original quantity before removal.
        "fulfilled": 1 // Was fulfilled before return.
      },
      "totals": [
        {"type": "subtotal", "amount": 14900},
        {"type": "tax", "amount": 1200},
        {"type": "total", "amount": 16100}
      ],
      "status": "removed" // Item is cancelled, returned, or refunded.
    }
  ],
  "totals": [
    {"type": "subtotal", "amount": 14900},
    {"type": "tax", "amount": 1200},
    {"type": "total", "amount": 16100}
  ],
  "fulfillment": {
    "events": [
      {
        "id": "fulfill_evt_1",
        "occurred_at": "2026-02-05T09:00:00Z",
        "type": "shipped",
        "line_items": [{ "id": "line_3", "quantity": 1 }],
        "tracking_number": "987654321",
        "tracking_url": "https://fedex.com/track/987654321",
        "carrier": "FedEx",
        "description": "Item shipped"
      },
      {
        "id": "fulfill_evt_2",
        "occurred_at": "2026-02-07T16:00:00Z",
        "type": "delivered",
        "line_items": [{ "id": "line_3", "quantity": 1 }],
        "tracking_number": "987654321",
        "tracking_url": "https://fedex.com/track/987654321",
        "carrier": "FedEx",
        "description": "Item delivered"
      },
      {
        "id": "fulfill_evt_3",
        "occurred_at": "2026-02-09T09:00:00Z",
        "type": "returned",
        "line_items": [{ "id": "line_3", "quantity": 1 }],
        "tracking_number": "987654321",
        "tracking_url": "https://fedex.com/track/987654321",
        "carrier": "FedEx",
        "description": "Item returned"
      }
    ],
    "expectations": [{ "...": "..." }]
  },
  "adjustments": [
    {
      "id": "adj_return_1",
      "type": "return", // a matching fulfillment event is also added to represent return shipping.
      "description": "Item not compatible",
      "line_items": [{ "id": "line_3", "quantity": -1 }],  // Uses a negative value (such as -1) to indicate a return.
      "occurred_at": "2026-02-09T09:00:00Z",
      "status": "completed"
    },
    {
      "id": "adj_refund_2",
      "type": "refund",
      "description": "Refund for returned item",
      "line_items": [{ "id": "line_3", "quantity": -1 }],
      "totals": [
        {"type": "subtotal", "amount": -14900}, // Negative amounts indicate money returned to the buyer.
        {"type": "tax", "amount": -1200},
        {"type": "total", "amount": -16100}
      ],
      "occurred_at": "2026-02-10T10:00:00Z",
      "status": "completed"
    }
  ],
  "permalink_url": "https://merchant.example.com/orders/67890"
}