> ## Documentation Index
> Fetch the complete documentation index at: https://docs.goshippo.com/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Shippo is a multi-carrier shipping API. For agent integrations that execute shipping operations (rates, labels, tracking, address validation, customs), connect the hosted Shippo MCP server at https://mcp.shippo.com (per-user OAuth; setup at /guides/mcp-server). To search and read this documentation from an agent, a docs search MCP is available at https://docs.goshippo.com/mcp. Shipping workflow knowledge (agent skills and a knowledge pack) is published at https://github.com/goshippo/ai. For REST integrations start at /guides/api-quickstart; test mode uses shippo_test_ API keys.

# Purchase label

> Purchase a Royal Mail Tracked shipping label by submitting a rate object ID to the Shippo transactions endpoint.

This is a 2nd step of the label purchase flow where we first create a shipment object (and get rates for a given shipment). Then, we purchase a label for the provided ‘rate’.

## HTTP Method

POST

## URL

```
https://api.goshippo.com/transactions/
```

## Purchase from created Shipment

This is a flow where we first create a shipment object (and get rates for a given shipment). Then, we purchase a label for the provided `rate`.

### Request Payload

| Parameter           | Description                                                                                                                                                     |
| ------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| rate\*              | `object_id` of the rate object we get in the [create shipments call response](/carriers/integration-guides/royal-mail-tracked/create-shipment#response-sample). |
| label\_file\_type\* | Allowed values: `PDF`, `PDF_A4`                                                                                                                                 |
| async               | Set to true if you want to poll for the result and receive faster response                                                                                      |

Note: Parameters with an \* are mandatory

### Example

#### Request Sample

```shell cURL theme={null}
curl --location --request POST 'https://api.goshippo.com/transactions' \
--header 'Authorization: ShippoToken <API_TOKEN>’ \
--header 'Content-Type: application/json' \
--data-raw '{
    "rate": "32444e5afe5c4d5fa44de02e4b56870d",
    "async": false,
    "label_file_type": "PDF"
}'

```

#### Response Sample

```json theme={null}
{
   "object_state": "VALID",
   "status": "SUCCESS",
   "object_created": “2025-08-05T21:43:41.829Z”,
   "object_updated":“2025-08-05T21:43:41.829Z”,
   "object_id": "cbc1a12243db44b9ae56ef3ca502b8c3",
   "object_owner": expn-prod-test@goshippo.com",
   "test": false,
   "rate": "32444e5afe5c4d5fa44de02e4b56870d",
   "tracking_number": "TQ966044837GB",
   "tracking_status": "PRE_TRANSIT",
   "eta": null,
   "tracking_url_provider": "",
   "label_url": "you_will_find_your_label_url_here",
   "commercial_invoice_url": null,
   "messages": [],
   "order": null,
   "metadata": "",
   "parcel": "bf276a9f955f43e7b7a75345687b9f4d",
   "billing": {
       "payments": []
   },
   "qr_code_url": null
}
```

## Sample Label

Below is a sample PDF label for a Royal Mail C2C MCA Tracked 48 for Post Office Drop.

<img src="https://mintcdn.com/shippo-f4b7b609/Em2SaRCKsbbZ5YDS/images/Carriers/RM_sample_label.png?fit=max&auto=format&n=Em2SaRCKsbbZ5YDS&q=85&s=e0b145de38ea9ce50a6f5b19fc7b1600" alt="" width="940" height="1296" data-path="images/Carriers/RM_sample_label.png" />

After you have created your label and shipped your package, you may request tracking status updates by following the process described in [Step 4: Track](/carriers/integration-guides/royal-mail-tracked/track).


## Related topics

- [Purchase label](/carriers/integration-guides/colissimo/purchase-label.md)
- [Using your Platform Account](/platform-accounts/platform-using-accounts.md)
- [Appendix](/partner-integration/appendix.md)