# User data

Source: https://developer.avalara.com/products/excise/integration-guides/excise/ifz9614617031169/

Guide: AvaTax Excise

# User data

Learn about the `UserData` field in RestTransaction and RestTransactionLine models, including its purpose and usage.

**Element type**: Suggested

**Endpoints/models used**: [RestTransaction](https://developer.avalara.com/api-reference/excise/v1/models/Avalara.Excise.Determination.Engine.RestTransaction/), [RestTransactionLine](https://developer.avalara.com/api-reference/excise/v1/models/Avalara.Excise.Determination.Engine.RestTransactionLine/)

Users should be provided with a field for holding any data they may want to pass into a transaction and/or a transaction line and potentially receive back untouched. This is done using the `UserData` field in the [RestTransaction](https://developer.avalara.com/api-reference/excise/v1/models/Avalara.Excise.Determination.Engine.RestTransaction/) and [RestTransactionLine](https://developer.avalara.com/api-reference/excise/v1/models/Avalara.Excise.Determination.Engine.RestTransactionLine/) models. This field can also be used for customizing calculations based on business rules. When passed, this field will display in the response in the `UserReturnedValue` field.

## Example

```
{
    "EffectiveDate": "2024-09-01T15:53:23.769Z",
    "InvoiceDate": "2024-09-01T15:53:23.769Z",
    "InvoiceNumber": "Test_NIC",
    "TitleTransferCode": "DEST",
    "TransactionType": "WHOLESALE",
    "Seller": "RESELLER",
    "Buyer": "CUSTOMER",
    "UserTranId": "CarisamTest1",
    "EntityUseCode": "",
    "CustomString1": "Header1",
    "CustomString2": "Header2",
    "CustomString3": "Header3",
    "CustomString4": "",
    "CustomString5": "",
    "CustomString6": "",
    "CustomString7": "",
    "CustomString8": "",
    "CustomString9": "",
    "CustomString10": "",
    "CustomNumeric1": 0,
    "CustomNumeric2": 0,
    "CustomNumeric3": 0,
    "CustomNumeric4": 0,
    "CustomNumeric5": 0,
    "CustomNumeric6": 0,
    "CustomNumeric7": 0,
    "CustomNumeric8": 0,
    "CustomNumeric9": 0,
    "CustomNumeric10": 0,
    "UserData": "Test_Nicotine",
    "SourceSystem": "POSTMAN",
    "AvataxTransactionType": "SalesInvoice",
    "Discount": "0.00",
    "TransactionLines": [
        {
            ...
        }
    ]
}
```