# POST /billing/invoices/process
URL: https://developers.vsee.io/api/payment-api/post/billing/invoices/process
Auth: User Token — Requires a user access token from login or SSO.

Process invoice

Process an invoice with optional coupon code

Process an invoice, optionally applying a promo/coupon code.

**Parameters:**
- `promo_code` — Coupon code
- `intake_id` — Required — intake ID to apply the coupon to
- `create_invoice` — Set to `1` to create the invoice

Parameters:
- X-ApiToken (header, string, required) — API token
- X-AccountCode (header, string, required) — Account code

Request body (application/json):
- promo_code (string, optional)
- intake_id (string, required)
- create_invoice (integer, optional)

Example request:
```json
{
  "promo_code": "string",
  "intake_id": "string",
  "create_invoice": 0
}
```

Responses:
- 200 — Successful processing
```json
{
  "data": {
    "currency": "USD",
    "consultation": {
      "description": "30 mins",
      "amount": 30,
      "duration": 30,
      "id": "58244a53-0f28-4ff9-bdbc-7468ac1f0144"
    },
    "coupon": {
      "id": "10_percents_1479363579",
      "percent_off": 10,
      "valid": true
    },
    "amount_due": 27
  }
}
```