October 21, 2026

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Credit and Base Amounts on Payments

GET /v3/Payments and GET /v3/Payments/{PaymentKey} now return two new fields, so you can see how much of a payment is still available as credit:

Field	Description
`CreditAmount`	The credit still available on the payment: the payment amount before surcharges less any amounts applied to invoices. Returned after `GrossAmount`.
`KarbonPayment.BasePaymentAmount`	The payment amount before surcharges: `GrossAmount` less `SurchargeAmount` and `SurchargeTaxAmount`. Returned after `PayoutStatus`.

For example, a $2,244.00 card payment with a $40.00 surcharge, $4.00 surcharge tax and $2,100.00 applied to invoices returns:

{
  "PaymentKey": "rE3qYC48lv",
  "PaymentReference": "KPY-1001",
  "PaymentType": "Payment",
  "PaymentDate": "2026-08-04",
  "GrossAmount": 2244,
  "CreditAmount": 100,
  "PaymentMethod": "CreditCardOnline",
  "ClientKey": "vTx6YRgMk4",
  "KarbonPayment": {
    "PayoutStatus": "Success",
    "BasePaymentAmount": 2200,
    "SurchargeAmount": 40,
    "SurchargeTaxAmount": 4,
    ...
  }
}

A payment with nothing applied returns a CreditAmount equal to its base amount. A fully applied, reversed or deleted payment returns a CreditAmount of 0.

Manual payments return CreditAmount but have no KarbonPayment object, so BasePaymentAmount is only returned for Karbon Payments. A manual payment has no surcharge, so its base amount is its GrossAmount.

These fields are additive. All other fields are unchanged.

Refer to the API documentation for more information on retrieving payments.