## POST /api/v2/billing/credit/actions/add-funds

**Create credit top-up invoice**

Create an unpaid invoice for adding account credit. This action does not start a payment session and does not return a customer-facing payment URL. To pay the invoice, use the returned `paymentLinkGeneratorUrl`, `POST /api/v2/billing/invoices/{id}/actions/pay`, or the normal invoice payment flow.

### Related Endpoints

- `GET /api/v2/billing/cards`: List saved cards
- `POST /api/v2/billing/cards`: Store saved card
- `GET /api/v2/billing/activity`: List billing activity

### Headers

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

### Request Body

- `amount` (number, required) [max: 100000]: Amount to add in the authenticated account's currency. The created invoice returns its `currencyCode`. Example: `250`

### Request Examples

#### Create credit invoice

```bash
curl -X POST "https://cloud.hostup.se/api/v2/billing/credit/actions/add-funds" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json" \
  -H "Content-Type: application/json" \
  -d '{
    "amount": 250
  }'
```

```json
{
  "amount": 250
}
```

### Response Schema

- `invoice` (object, required)
- `invoice.id` (string, required) Example: `inv_01hxa3b4c5d6e7f8g9h0j1k2m3`
- `invoice.number` (string,null, required) Example: `202600001`
- `invoice.amount` (number,null, required) Example: `250`
- `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: `/billing?invoice=202600001`
- `paymentLinkGeneratorUrl` (string, required) Example: `/api/v2/billing/invoices/inv_01hxa3b4c5d6e7f8g9h0j1k2m3/actions/generate-payment-link`

### Responses

#### 200 - Credit invoice created.
```json
{
  "invoice": {
    "id": "inv_01hxa3b4c5d6e7f8g9h0j1k2m3",
    "number": "202600001",
    "amount": 250,
    "currencyCode": "SEK",
    "dueAt": "2026-05-11T23:59:59.000Z",
    "status": "unpaid",
    "paymentUrl": "/billing?invoice=202600001"
  },
  "paymentLinkGeneratorUrl": "/api/v2/billing/invoices/inv_01hxa3b4c5d6e7f8g9h0j1k2m3/actions/generate-payment-link"
}
```

#### 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"
}
```

#### 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"
}
```