# Tax code

Source: https://developer.avalara.com/vat-ecom/transactions/certification-requirements/tax-code/

**Element type:** Required

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

Your UI must include a method for allowing users to specify a tax code for each line item in a transaction. You can use your own tax code mapping or you can use standard Avalara tax codes. For a full list of tax codes, run the [ListTaxCodes](https://developer.avalara.com/api-reference/avatax/rest/v2/methods/Definitions/ListTaxCodes/) API, or you can use the [Avalara Tax Code Search](https://taxcode.avatax.avalara.com/) tool.

Tax codes are specified using the `taxCode` field on the [LineItemModel](https://developer.avalara.com/api-reference/avatax/rest/v2/models/LineItemModel/). This field is optional for users. If a `taxCode` isn't specified, then AvaTax will treat that item as a taxable item. More information about Avalara tax codes is available in the [Avalara tax codes](https://knowledge.avalara.com/bundle/dqa1657870670369_dqa1657870670369/page/Avalara_tax_codes.html) article in the Knowledge Center.

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

```
{    ...,  "lines": [    {      "number": "1",      "quantity": 1,      "amount": 100,      "taxCode": "PS081282",      "itemCode": "Y0001",      "description": "Yarn"    }  ],  ...} 
```