# Party C VAT ID country

Source: https://developer.avalara.com/vat-erp/certification-requirements/party-c-vat-id-country/

**Element type:** Suggested for Triangulation

**Endpoints/models used:** [TransactionParameterModel](https://developer.avalara.com/api-reference/avatax/rest/v2/models/TransactionParameterModel/), [TransactionLineParameterModel](https://developer.avalara.com/api-reference/avatax/rest/v2/models/TransactionLineParameterModel/)

The `PartyCVATIDCountry` parameter is used in triangulation transactions to verify that Party C has provided a VAT ID for the country where the goods are shipping to. Users must specify this field for "Sale Party B to Party A" use cases when `IsTriangulation` isn't passed. When configuring the `PartyCVATIDCountry`, specify the country's 2-digit country ISO code.

If you don't include this field in your integration, then users can specify `"IsTriangulation": true`, and AvaTax will recognize that this is a triangulation transaction.

[![Closed](https://avalara-devdocs-prod.mcoutput.com/vat-erp/Skins/Default/Stylesheets/Images/transparent.gif)View example](javascript:void\(0\);)

```
 ...  "parameters": [    {      "name": "MiddlemanVatId",      "value": "RO123456"    },    {      "name": "PartyCVATIDCountry",      "value": "IE"    },    {      "name": "Transport",      "value": "Seller"    }... 
```