# Merchant Custom Data
source: https://developer.mastercard.com/mastercard-gateway/documentation/gateway-features/data-and-reporting/supp-data/merchant-custom-data/index.md

Merchants can include custom transaction data for reporting and analysis that cannot be passed using other available data fields. Custom data fields are returned in the response.

| Integration methods | Payment methods |            Transactions            |
|---------------------|-----------------|------------------------------------|
| All                 | All             | All, except retrieval transactions |

To view the API request example with merchant custom data, download the [Postman collection](https://www.postman.com/mastercard/mastercard-developers/collection/4fakvrd/mastercard-gateway-api).

To process the transaction, your payment service provider or the acquirer does not need custom merchant data.
Warning: Do not include sensitive data in any of the merchant custom data fields.

You can create fields and values for the merchant customer data, and then submit it in the `order.custom` object. For example, to define the sales region related to the order, create a `salesRegion` field and use it as `order.custom.salesRegion`.

The submitted data is returned in the transaction response.

### Example of merchant custom data fields {#example-of-merchant-custom-data-fields}

```json
{
  "order": {
    "amount": "100.00",
    "currency": "USD",
    "custom": {
      "shoppingList": "Orange juice, milk, bread",
      "favoriteColor": "Green"
    }
  }
}
```

**Merchant Custom Data API Reference** [\[REST\]](https://developer.mastercard.com/mastercard-gateway/documentation/api-reference/v100/rest/api-ops/index.md#transaction.md) [\[NVP\]](https://developer.mastercard.com/mastercard-gateway/documentation/api-reference/v100/nvp/api-ops/index.md#transaction.md)