Creates a refund against a source payment.

POST /accounting/refunds

Group: Accounting › Refunds · Operation ID: createRefund

Creates a refund against a source payment. When the payment lacks enough unapplied balance, list invoices in unapply to free balance first, in the same request. The refund is created approved, which triggers the external payment-provider sync, so there is no separate approval step over this API. customerId, entityId and currency are not inputs. They are derived from the source payment, so a refund cannot disagree with the payment it is against.

Open in the interactive reference

Parameters

Name	In	Type	Required	Description
`Api-Version`	header	`"v1"`	yes	The API version this request targets, named by its public identifier. Required on every request; omitting it, or naming a version this company does not have, is answered with 400. This document describes version `v1`.
`Idempotency-Key`	header	string	no	An opaque caller-chosen string (1-255 characters) that makes this request safe to retry. Repeating the same key with an identical request body replays the original response instead of re-executing - but only once that original request succeeded; a failed attempt re-executes on retry. Repeating the key with a different body is answered with 422. A key still in flight is answered with 409 - as is a key whose original request was interrupted before it finished, for a few minutes afterwards, until that attempt is presumed dead. A completed response stays replayable for 24 hours. The key is scoped to the caller, not to the action: reusing it for a different action is answered with 409 or 422 rather than treated independently. On read actions this header is ignored. On write actions that cannot offer the guarantee it is answered with `400 IDEMPOTENCY_NOT_SUPPORTED` rather than silently ignored.

Request body

Required, application/json: createRefundInput.

Field	Type	Required	Description
`paymentId`	string	yes	The source payment being refunded. See id on GET accounting/payments/:id.
`refundDate`	string (date)	yes	The date the refund is issued. Use format YYYY-MM-DD. Must fall in an open accounting period.
`refundType`	string, one of `"check"`, `"ach"`, `"wire"`, `"creditCard"`, `"directDebit"`, `"sepaCreditTransfer"`	yes	The payment method used for the refund.
`amount`	string (decimal)	yes	The refund amount, in the source payment's currency. Must be greater than 0.
`refundNote`	string	no	A free-form note attached to the refund.
`unapply`	array of object	no	Invoices to unapply the source payment from before the refund is created, freeing balance for the refund. The amount unapplied from each invoice is recognized on refundDate.
`unapply[].invoiceId`	string	yes	The invoice to unapply the payment from. See id on GET accounting/invoices/:id.
`unapply[].amount`	string (decimal)	yes	The amount to unapply from this invoice, in the payment currency.

Example:

{
  "paymentId": "5a0f3e6d-81b7-4c8e-9b21-9c2a6a107d34",
  "refundDate": "2026-08-01",
  "refundType": "ach",
  "amount": "150.00",
  "refundNote": "Customer requested partial refund",
  "unapply": [
    {
      "invoiceId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "amount": "19.99"
    }
  ]
}

Response

200 Success

Under data (createRefundOutput):

Field	Type	Required	Description
`id`	string	yes	The unique identifier for the created refund.
`refundNumber`	string	no	The refund number, unique within the tenant, for example 'REF-1042'. Assigned on create.
`refundDate`	string (date)	yes	The date the refund was issued. Format YYYY-MM-DD.
`approvalStatus`	string	no	The approval status, always 'approved' immediately after create.
`refundType`	string	yes	The payment method used for the refund. Possible values: 'check', 'ach', 'wire', 'creditCard', 'directDebit', 'sepaCreditTransfer'.
`currency`	string	yes	The currency of the refund, derived from the source payment. Every amount on it is in this currency. Format ISO 4217, for example 'USD'.
`amount`	string (decimal)	yes	The refund amount, in the refund currency.
`customerId`	string	yes	The customer receiving the refund, derived from the source payment. See id on GET accounting/customers/:id.
`entityId`	string	yes	The legal entity issuing the refund, derived from the source payment. See id on GET base/entities.
`paymentId`	string	yes	The source payment being refunded. See id on GET accounting/payments/:id.
`lastModifiedDate`	string (date-time)	yes	The date and time the refund last changed, in UTC. Format YYYY-MM-DDTHH:mm:ss.sssZ.

Response headers

Idempotency-Replayed — Present and true only when this response replays a previously stored one for the same Idempotency-Key, rather than reflecting a live execution. Absent on a live response - never sent as false.

Errors

Code	Status
`PAYMENT_NOT_FOUND`	400
`INVOICE_NOT_FOUND`	400
`INVALID_AMOUNT`	400
`IDEMPOTENCY_KEY_CONFLICT`	409
`IDEMPOTENCY_PAYLOAD_MISMATCH`	422

Statuses

400 — Invalid request or business failure. Codes: PAYMENT_NOT_FOUND, INVOICE_NOT_FOUND, INVALID_AMOUNT
401 — Missing or invalid access token
403 — Not authorized
404 — Not found
409 — The Idempotency-Key is still being processed by another request.
422 — The Idempotency-Key was already used with a different request payload.
429 — Too many requests
500 — Internal server error