# Complete cart checkout

Complete checkout for cart items using saved payment method or account balance. Requires authentication.

Endpoint: POST /mcp/v1/actions/ud_cart_checkout
Version: 1.0.0
Security: bearerAuth

## Request fields (application/json):

  - `paymentMethodId` (string)
    Stripe payment method ID for card payment. Required if cart total exceeds account balance.

  - `useAccountBalance` (boolean)
    Whether to apply account balance to reduce total. Defaults to true.

  - `discountCode` (string)
    Optional discount/promo code to apply

  - `contactId` (string)
    ICANN contact ID for DNS domain registration. Get IDs from ud_contacts_list. If not specified, uses the most recent contact.

## Response 200 fields (application/json):

  - `success` (boolean)

  - `orderId` (number)

  - `paymentId` (number)

  - `summary` (object)

  - `summary.itemCount` (number)

  - `summary.domains` (array)

  - `summary.subtotal` (number)

  - `summary.subtotalFormatted` (string)

  - `summary.discounts` (number)

  - `summary.discountsFormatted` (string)

  - `summary.creditsUsed` (number)

  - `summary.creditsUsedFormatted` (string)

  - `summary.salesTax` (number)

  - `summary.salesTaxFormatted` (string)

  - `summary.totalCharged` (number)

  - `summary.totalChargedFormatted` (string)

  - `summary.paymentMethod` (string)

  - `note` (string)
    Optional note about contact selection when user has multiple contacts


## Response 401 fields