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)
With the application of Soft Decline, the vads_sequence_number field no longer allows to easily identify the first installment of a payment in installments.
To identify the first payment of a series, view the description of the vads_occurrence_type field.
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).