## POST /api/v2/billing/invoices/{id}/actions/generate-payment-link

**Generate invoice payment link**

Create or reuse a customer-facing payment URL for an unpaid invoice. The request body must be empty: payment method selection is not accepted here. For Swish, send the returned `paymentUrl` to the payer; this v2 action does not return a raw Swish QR code or token.

### Related Endpoints

- `GET /api/v2/billing/invoices/{id}/payment-link`: Get invoice payment link state
- `GET /api/v2/billing/invoices/{id}`: Get invoice details
- `POST /api/v2/billing/invoices/{id}/actions/pay`: Pay invoice by saved card

### Headers

- `Accept`: application/json
- `Authorization`: Bearer YOUR_API_KEY
- Required API scope: `write:billing`

### Parameters

- `id` (path, string, required): Public invoice ID from `GET /api/v2/billing/invoices` `data[].id`, invoice detail, or an order response. Do not invent this value; use the exact ID returned by the referenced API response. Example: `inv_01hxa3b4c5d6e7f8g9h0j1k2m3`
- `Content-Type` (header, string): Send `application/json` when a request body is present. Example: `application/json`
- `Accept` (header, string): Request JSON responses from the API. Example: `application/json`

### Request Examples

#### Generate payment URL

```bash
curl -X POST "https://cloud.hostup.se/api/v2/billing/invoices/inv_01hxa3b4c5d6e7f8g9h0j1k2m3/actions/generate-payment-link" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json"
```

### Response Schema

- `paymentUrl` (string, optional): Customer-facing invoice payment URL. Send this URL to the payer for card, Swish, or other available payment methods. Example: `https://cloud.hostup.se/billing/pay/550e8400-e29b-41d4-a716-446655440000`
- `expiresAt` (string,null, optional) Example: `2026-05-27T12:00:00.000Z`
- `invoice` (object, optional)
- `invoice.id` (string, required) Example: `inv_01hxa3b4c5d6e7f8g9h0j1k2m3`
- `invoice.number` (string,null, required) Example: `202600001`
- `invoice.amount` (number,null, required) Example: `159`
- `invoice.currencyCode` (string, required) Example: `SEK`
- `invoice.dueAt` (string,null, required) Example: `2026-05-11T23:59:59.000Z`
- `invoice.status` (string, required) Example: `unpaid`
- `invoice.paymentUrl` (string,null, required) Example: `https://cloud.hostup.se/billing/pay/550e8400-e29b-41d4-a716-446655440000`

### Responses

#### 200 - Generated invoice payment link.
```json
{
  "paymentUrl": "https://cloud.hostup.se/billing/pay/550e8400-e29b-41d4-a716-446655440000",
  "expiresAt": "2026-05-27T12:00:00.000Z",
  "invoice": {
    "id": "inv_01hxa3b4c5d6e7f8g9h0j1k2m3",
    "number": "202600001",
    "amount": 159,
    "currencyCode": "SEK",
    "dueAt": "2026-05-11T23:59:59.000Z",
    "status": "unpaid",
    "paymentUrl": "https://cloud.hostup.se/billing/pay/550e8400-e29b-41d4-a716-446655440000"
  }
}
```

#### 400 - Invalid request. The response body is an RFC 7807 Problem Details document.
```json
{
  "type": "https://developer.hostup.se/errors/invalid_request",
  "title": "Invalid request",
  "status": 400,
  "detail": "The request body failed validation.",
  "code": "invalid_request",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z",
  "errors": [
    {
      "pointer": "/items/0/domainName",
      "detail": "`domainName` is required.",
      "code": "invalid_request"
    }
  ]
}
```

#### 401 - Unauthorized. Authentication is required.
```json
{
  "type": "https://developer.hostup.se/errors/unauthorized",
  "title": "Unauthorized",
  "status": 401,
  "detail": "Authentication is required.",
  "code": "unauthorized",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```

#### 403 - Forbidden. The caller lacks a required scope or does not own the resource.
```json
{
  "type": "https://developer.hostup.se/errors/forbidden",
  "title": "Forbidden",
  "status": 403,
  "detail": "The caller lacks a required scope or does not own the resource.",
  "code": "forbidden",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```

#### 404 - Not found. The resource does not exist or is not owned by the caller.
```json
{
  "type": "https://developer.hostup.se/errors/not_found",
  "title": "Not found",
  "status": 404,
  "detail": "The requested resource could not be found.",
  "code": "not_found",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```

#### 409 - Conflict. See the Problem Details `code` for the route-specific blocker and recovery fields.
```json
{
  "status": 409,
  "instance": "/api/v2/billing/invoices/inv_01hxa3b4c5d6e7f8g9h0j1k2m3/actions/generate-payment-link",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z",
  "type": "https://developer.hostup.se/errors/invoice_already_paid",
  "title": "Invoice already paid",
  "detail": "Invoice #202600001 has already been paid.",
  "code": "invoice_already_paid",
  "invoice": {
    "id": "inv_01hxa3b4c5d6e7f8g9h0j1k2m3",
    "number": "202600001",
    "status": "paid"
  },
  "actions": {
    "canGeneratePaymentLink": {
      "allowed": false,
      "reason": "Invoice #202600001 has already been paid."
    }
  }
}
```

#### 429 - Rate limited. Retry after the limit resets. 429 responses include `Retry-After` seconds plus `X-RateLimit-*` headers.
```json
{
  "type": "https://developer.hostup.se/errors/rate_limit_exceeded",
  "title": "Too many requests",
  "status": 429,
  "detail": "Too many requests. Retry after the limit resets.",
  "code": "rate_limit_exceeded",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```

#### 500 - Internal error. Retry later or contact support if the issue persists.
```json
{
  "type": "https://developer.hostup.se/errors/internal_error",
  "title": "Internal server error",
  "status": 500,
  "detail": "An unexpected error occurred. Retry later or contact support if the issue persists.",
  "code": "internal_error",
  "instance": "/api/v2/resource",
  "requestId": "req_01hxa3b4c5d6e7f8g9h0j1k2m3",
  "timestamp": "2026-04-27T12:34:56.000Z"
}
```