Select Installment Option for BKM Express

Sets the selected installment option for the BKM Express payment.

Required Fields:

• installment: The installment_count integer (e.g., 1 for single payment, 3 for three installments). This is not a primary key — it is the installment count value. The system looks up the matching active Installment record for the resolved card by installment_count.

Validation:

• installment must match an active Installment record linked to the card resolved in BexBinNumberPage. If no matching record is found, pre_order.installment is set to null (no explicit error message is returned for this case; the flow simply does not advance past this page).

• If pre_order.card_info is not set at validation time, a validation error is returned with the message "You need to enter your card number".

State Update:

• pre_order.installment is set to the resolved Installment object.

Next Pages:

• BexNoncePage

available_for_post_order: true

post

Header parameters

x-requested-withstring · enumRequired

Required header for AJAX requests. Must be set to XMLHttpRequest for all checkout requests.

Default: XMLHttpRequestPossible values:

CookiestringOptional

Session cookie header (e.g. sessionid=abc123 or osessionid=<session_id>)

Body

installmentintegerRequired

The installment count to select (e.g., 1 for single payment, 3 for three installments). This is not a primary key. The system resolves the matching active Installment record for the card by installment_count.

Example: 3

Responses

200

Installment selected successfully

application/json

errorsone of · nullableOptional

or

string[]Optional

template_namestringOptional

post/orders/checkout/?page=BexInstallmentSelectionPage

POST /orders/checkout/?page=BexInstallmentSelectionPage HTTP/1.1
Host: sandbox.akinon.com
x-requested-with: XMLHttpRequest
Content-Type: application/x-www-form-urlencoded
Accept: */*
Content-Length: 17

"installment=1"

200

Installment selected successfully

{
  "context_list": [
    {
      "page_name": "BexNoncePage",
      "page_slug": "bexnoncepage",
      "page_context": {}
    }
  ],
  "pre_order": {
    "basket": {
      "pk": 123,
      "total_amount": "150.00"
    },
    "payment_option": {
      "pk": 5,
      "name": "BKM Express",
      "slug": "bkm-express",
      "payment_type": "bkm_express",
      "payment_type_label": "BKM Express"
    },
    "number": "ORD-2026-0001",
    "card_info": {
      "bin_number": "542119",
      "card": {
        "pk": 1,
        "name": "Visa"
      }
    },
    "installment": {
      "pk": 2,
      "installment_count": 3,
      "label": "3 Installments",
      "price_with_accrued_interest": "165.59",
      "monthly_price_with_accrued_interest": "55.20"
    },
    "total_amount": "165.59",
    "total_amount_with_interest": "165.59",
    "currency_type_label": "TRY"
  },
  "errors": {},
  "template_name": "orders/checkout.html"
}