curl --request POST \
  --url https://api.bkey.id/v1/checkout/initiate \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "merchantName": "<string>",
  "merchantDomain": "<string>",
  "checkoutUrl": "<string>",
  "amount": 2,
  "lineItems": [
    {
      "title": "<string>",
      "quantity": 2,
      "price": 1
    }
  ],
  "currency": "USD",
  "expiresInSecs": 600
}
'

{
  "success": true,
  "checkoutRequest": {
    "id": "<string>",
    "status": "<string>",
    "challengeHex": "<string>",
    "expiresAt": "2023-11-07T05:31:56Z",
    "createdAt": "2023-11-07T05:31:56Z",
    "sptId": "<string>",
    "paymentIntentId": "<string>"
  }
}