Optionalcard_type?: Optionalclient_transaction_id?: stringClient-specific ID of the transaction.
Optionaltransaction_id?: SumUp.Transactions.TransactionIDOptionaltype?: "PAYMENT" | "REFUND" | "CHARGE_BACK"Type of the transaction for the registered user specified in the user property.
Optionaluser?: stringEmail address of the registered user (merchant) to whom the payment is made.
Issuing card network of the payment card used for the transaction.