Transaction sequence number.
Case of single payment (vads_payment_config=SINGLE)
vads_sequence_number is populated with 1 in case of single payment.
However, if the merchant has authorized several payment attempts after a rejected payment, the sequence number will be incremented upon each new attempt.
The number of additional attempts after a rejected payment can be configured via the Expert Back Office (menu Settings > Shop > Configuration).
If vads_payment_config = SINGLE :
Case of installment payment (vads_payment_config=MULTI)
For an installment payment, this field will take the "1" value for the first installment, "2" for the second installment, "3" for the third installment, etc.
Installment payments are not compatible with the feature of additional attempts in case of a rejected payment.
Case of a cascading payment (vads_card_brand=MULTI)
In case of a cascading payment (the cart items are paid with several payment methods), the vads_sequence_number field is always set to 0.
The vads_payment_seq field describes each transaction in a table in JSON format.
The transaction[x].sequence_number attribute takes the same values as the vads_sequence_number field, as described for the case of single payment.
The vads_sequence_number field is not returned in the response when a payment is canceled or abandoned.
Output field, returned in the response (IPN and Return URL).