# POST /api/invoicing/invoices/{id}/refund

Invoices: Refunds the payments collected against an invoice.

Returns the money to the payer and moves the invoice to Refunded.
Gateway payments delegate to the payment platform, which returns the money with whichever
operation the originating transaction's settlement state permits. Manually-recorded payments
are reversed in place and require a reason.

**Operation ID:** `invoiceLifecycleRefund`

## Authorization

Requires: Invoicing.Invoices, Invoicing.Invoices.Refund, merchant scope.

Required permissions:
- `Invoicing.Invoices`
- `Invoicing.Invoices.Refund`

## Parameters

| Name | In | Required | Type | Description |
| --- | --- | --- | --- | --- |
| id | path | yes | string(uuid) |  |
| suppressNulls | query | no | boolean | If true, omit properties with null values. |

## Request Body

**Content type:** `application/json`

Schema: `RefundInvoiceInput`

Properties:
- `reason` (string): Operator-supplied reason for the refund. Recorded on the refund entry and on the invoice's  activity timeline, and threaded onto the gateway operation's audit note.
- `idempotencyKey` (string): Optional caller-supplied idempotency key. When omitted, the service derives a deterministic  key per refunded payment so a retry after a timeout replays the original outcome rather than  returning the money twice. Conditional: When IdempotencyKey is not empty. Pattern: ^[A-Za-z0-9._:-]+$.

**Content type:** `text/json`

Schema: `RefundInvoiceInput`

Properties:
- `reason` (string): Operator-supplied reason for the refund. Recorded on the refund entry and on the invoice's  activity timeline, and threaded onto the gateway operation's audit note.
- `idempotencyKey` (string): Optional caller-supplied idempotency key. When omitted, the service derives a deterministic  key per refunded payment so a retry after a timeout replays the original outcome rather than  returning the money twice. Conditional: When IdempotencyKey is not empty. Pattern: ^[A-Za-z0-9._:-]+$.

**Content type:** `application/*+json`

Schema: `RefundInvoiceInput`

Properties:
- `reason` (string): Operator-supplied reason for the refund. Recorded on the refund entry and on the invoice's  activity timeline, and threaded onto the gateway operation's audit note.
- `idempotencyKey` (string): Optional caller-supplied idempotency key. When omitted, the service derives a deterministic  key per refunded payment so a retry after a timeout replays the original outcome rather than  returning the money twice. Conditional: When IdempotencyKey is not empty. Pattern: ^[A-Za-z0-9._:-]+$.

## Responses

### 200

The refund completed and the invoice reflects it.

**Content type:** `application/json`

Schema: `InvoiceDto`

Properties:
- `extraProperties` (object)
- `id` (string(uuid))
- `creationTime` (string(date-time)): The date and time when this entity was created.
- `creatorId` (string(uuid)): The ID of the user who created this entity.
- `lastModificationTime` (string(date-time)): The date and time when this entity was last modified.
- `lastModifierId` (string(uuid)): The ID of the user who last modified this entity.
- `isDeleted` (boolean): Indicates whether this entity has been deleted.
- `deleterId` (string(uuid)): The ID of the user who deleted this entity, if it is deleted.
- `deletionTime` (string(date-time)): The date and time when this entity was deleted, if it is deleted.
- `tenantId` (string(uuid))
- `billerId` (string(uuid))
- `billerType` (InvoicePartyType): Identifies the type of entity acting as the biller or recipient on an invoice.
- `recipientId` (string(uuid))
- `recipientType` (InvoicePartyType): Identifies the type of entity acting as the biller or recipient on an invoice.
- `invoiceNumber` (string)
- `status` (InvoiceStatus): Represents the lifecycle status of an invoice.
- `isLocked` (boolean)
- `billerSnapshot` (InvoicePartySnapshotDto): Read DTO for denormalized biller/recipient info frozen at invoice issuance.
- `recipientSnapshot` (InvoicePartySnapshotDto): Read DTO for denormalized biller/recipient info frozen at invoice issuance.
- `currency` (string)
- `subtotal` (number(double))
- `taxTotal` (number(double))
- `discountTotal` (number(double))
- `grandTotal` (number(double))
- `amountPaid` (number(double))
- `balanceDue` (number(double))
- `invoiceLevelDiscount` (InvoiceDiscountDto): DTO for an invoice-level discount.
- `issueDate` (string(date-time))
- `dueDate` (string(date-time))
- `sentAt` (string(date-time))
- `viewedAt` (string(date-time))
- `paidAt` (string(date-time))
- `paymentTermsValue` (object)
- `customPaymentDays` (integer(int32))
- `allowPartialPayment` (boolean)
- `minimumPaymentAmount` (number(double))
- `partialPaymentTolerance` (number(double))
- `allowedPaymentMethods` (array<string>)
- `vaultRestriction` (object)
- `applyConvenienceFee` (boolean): Per-invoice override of the merchant's convenience fee on this invoice's payments.  `null` inherits the merchant and feature decision. `true` applies the fee only  when invoice convenience fees are enabled for the tenant.
- `depositRequest` (object): The deposit request on this invoice, if any. Null when no deposit was requested.
- `hppPageId` (string(uuid))
- `templateId` (string(uuid))
- `sourceType` (object)
- `sourceReferenceId` (string)
- `notes` (array<EntityNote>)
- `recipientNote` (string)
- `footerText` (string)
- `reminderConfig` (InvoiceReminderConfigDto): DTO for invoice reminder configuration. Each member overrides the tenant's reminder default on its  own; a member that is null or omitted inherits that default.
- `lineItems` (array<InvoiceLineItemDto>)
- `payments` (array<InvoicePaymentDto>)
- `activities` (array<InvoiceActivityDto>)
- `customFields` (array<CustomFieldValueDto>)
- `concurrencyStamp` (string)
- `entityVersion` (integer(int32))

### 403

Forbidden

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 401

Unauthorized

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 400

The request itself needs correcting. Callers branch on `error.code`:
`Invoicing:Refund:ManualReversalRequiresReason` (a manually recorded payment is being
reversed and no reason was supplied) or `Invoicing:Refund:AmountInvalid`.

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 404

The invoice does not exist or the caller cannot see it (`Invoicing:Invoice:NotFound`), or
it belongs to another biller (`Invoicing:Biller:ForeignBillerNotAllowed`).

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 501

Not Implemented

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 500

Internal Server Error

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 409

The invoice's current state refuses the refund. Callers branch on `error.code`:
`Invoicing:Refund:NotAllowedForStatus`, `Invoicing:Refund:NoRefundablePayments`,
`Invoicing:Refund:ExceedsAmountPaid`, `Invoicing:Refund:RequiresMerchantScope`,
`Invoicing:Refund:RejectedByGateway`, or `Invoicing:Refund:PartialFailure` (some
payments were returned before the sequence stopped; inspect the invoice before retrying).

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### default

The request failed. The body carries the standard error envelope: a machine-readable `error.code`, a human-readable `error.message`, and `error.validationErrors` when the failure was a validation rejection. See the error-code reference in this document's description for the values `error.code` can take.

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 429

The request was refused because a rate limit was exceeded, or because something a later retry can clear stopped it. A rate limit refusal carries an `application/problem+json` body: wait at least the interval `Retry-After` names before retrying, then back off. Limits are tuned per deployment, so read the allowance from the response headers rather than assuming a fixed ceiling. Any other refusal carries the standard error envelope as `application/json`, and its `error.code` names the cause.

**Content type:** `application/problem+json`

Schema: `RateLimitProblemDetails`

Properties:
- `type` (string) required: The problem type identifier. Always the same value: the failure is the status code itself,  so there is no sub-type for a caller to branch on.
- `title` (string) required: A short, human-readable summary of the problem type.
- `status` (integer(int32)) required: The HTTP status code, repeated in the body as the problem-details format defines.
- `detail` (string) required: A human-readable explanation of this occurrence of the problem.
- `retryAfterSeconds` (integer(int32)) required: How long to wait before retrying, in whole seconds, carrying the same figure as the  `Retry-After` header. Always at least one: a value of zero would invite an immediate  retry that is certain to be rejected again.

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

## Example request

Every block below sends the same request. Replace {{BASE_URL}} with the address of the API you are calling and {{API_KEY}} with your own key.

The request body is a RefundInvoiceInput. See the Request body section below for its fields.

### cURL

```bash
curl -X POST "{{BASE_URL}}/api/invoicing/invoices/{id}/refund" \
  -H "api-key: {{API_KEY}}" \
  -H "Content-Type: application/json" \
  -d '{
  "reason": "",
  "idempotencyKey": ""
}'
```

### PowerShell

```powershell
$headers = @{
    'api-key' = '{{API_KEY}}'
}

$body = @'
{
  "reason": "",
  "idempotencyKey": ""
}
'@

$response = Invoke-RestMethod -Method POST -Uri '{{BASE_URL}}/api/invoicing/invoices/{id}/refund' `
    -Headers $headers -ContentType 'application/json' -Body $body
```

### TypeScript (SDK)

```bash
npm install @winkpg/winkpg-api
```

```typescript
import { Configuration, InvoicingApi } from '@winkpg/winkpg-api';

const api = new InvoicingApi(new Configuration({
  basePath: '{{BASE_URL}}',
  apiKey: '{{API_KEY}}',
}));

const { data } = await api.invoiceLifecycleRefund("3fa85f64-5717-4562-b3fc-2c963f66afa6", {
  "reason": "",
  "idempotencyKey": ""
});
```

### TypeScript (raw HTTP)

```typescript
const response = await fetch('{{BASE_URL}}/api/invoicing/invoices/{id}/refund', {
  method: 'POST',
  headers: {
    "api-key": "{{API_KEY}}",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "reason": "",
    "idempotencyKey": ""
  }),
});

const data = await response.json();
```

### C# (SDK)

```bash
dotnet add package WinkPg.Api.Client
```

```csharp
using WinkPg.Api.Client.Api;
using WinkPg.Api.Client.Client;
using System.Text.Json;

var config = new Configuration { BasePath = "{{BASE_URL}}" };
config.AddApiKey("api-key", "{{API_KEY}}");

var api = new InvoicingApi(config);
var body = JsonSerializer.Deserialize<RefundInvoiceInput>("""
    {
      "reason": "",
      "idempotencyKey": ""
    }
    """);

var result = await api.InvoiceLifecycleRefundAsync(Guid.Parse("3fa85f64-5717-4562-b3fc-2c963f66afa6"), body);
```

### C# (raw HTTP)

```csharp
using System.Text;

using var http = new HttpClient { BaseAddress = new Uri("{{BASE_URL}}") };

var request = new HttpRequestMessage(new HttpMethod("POST"), "/api/invoicing/invoices/{id}/refund");
request.Headers.Add("api-key", "{{API_KEY}}");

request.Content = new StringContent("""
    {
      "reason": "",
      "idempotencyKey": ""
    }
    """, Encoding.UTF8, "application/json");

var response = await http.SendAsync(request);
response.EnsureSuccessStatusCode();
var json = await response.Content.ReadAsStringAsync();
```

### Python (SDK)

```bash
pip install winkpg-api
```

```python
import winkpg_api

configuration = winkpg_api.Configuration(host="{{BASE_URL}}")
configuration.api_key["ApiKey"] = "{{API_KEY}}"

with winkpg_api.ApiClient(configuration) as client:
    api = winkpg_api.InvoicingApi(client)
    body = winkpg_api.RefundInvoiceInput.from_dict({
      "reason": "",
      "idempotencyKey": ""
    })
    result = api.invoice_lifecycle_refund("3fa85f64-5717-4562-b3fc-2c963f66afa6", body)
```

### Python (raw HTTP)

```bash
pip install requests
```

```python
import requests

headers = {
    "api-key": "{{API_KEY}}",
    "Content-Type": "application/json",
}

body = {
  "reason": "",
  "idempotencyKey": ""
}

response = requests.request(
    "POST",
    "{{BASE_URL}}/api/invoicing/invoices/{id}/refund",
    headers=headers,
    json=body,
)
response.raise_for_status()
data = response.json()
```

## See also

- [All documentation](https://devportal-simpay-sbx.winkpg.io/llms.txt): the machine-readable index of every public page on this site.