# Merchant VAT ID

Source: https://developer.avalara.com/vat-marketplace/certification-requirements/merchant-vat-id/

**Element type:** Required

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

Your integration must provide a method for specifying the VAT ID of the merchant selling an item.

Keep in mind the following when using VAT input fields in marketplace transactions:

-   The `MerchantVatId` indicates the merchant’s VAT number. Most marketplaces collect this kind of information as part of an onboarding process. Users pass this value at the line level.

-   The `merchantSellerIdentifier`, `MerchantEstablishmentCountry`, `MerchantName`, and `MerchantVatId` fields should only ever contain the values of the merchant on the marketplace that are relevant to the goods referenced on that transaction line. These fields should never refer to the Avalara client.

    -   If the Avalara client is set up as a marketplace and is selling its own products, leave the above fields blank or omit them from the request. This is because AvaTax will assume that when these fields are blank, the items belong to the Avalara client and, therefore, won’t apply the deemed supplier logic.

-   Regardless of the `taxCode` type (freight, physical, digital, and so on), the `MerchantEstablishmentCountry` will always be the same whenever the related `merchantSellerIdentifier` is used. For example, if Line 1 has `merchantSellerIdentifier = "Seller123"` and `MerchantEstablishmentCountry = "CH"`, then those values should be used for every line where the merchant is `Seller123`.

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

```
"lines": [  {    "number": "1",    "amount": "50.0",    "taxCode": "P000000",    "itemCode": "Yarn",    "description": "green wool",    "businessIdentificationNo": "",    "merchantSellerIdentifier": "M6462",    "marketplaceLiabilityType": "Seller",    "originationSite": "S1Marketplace",    "parameters": [      {        "name": "MerchantEstablishmentCountry",        "value": "AT"      },      {        "name": "MerchantName",        "value": "Merchant Company Name LLC"      },      {        "name": "MerchantVatId",        "value": "ATU12233456"      }    ]  ]] 
```