The order in which debit transactions are paid off is determined by the payment hierarchy, which sorts transactions into groups. For more information about payment hierarchies, refer to How the program discharges transactions.

Within a group, the order in which transactions are paid off is determined by their charge order. Transactions with a lower charge order value are paid off before transactions in the same group with a higher value.

The charge order can be set at the program level or at the account level. The charge order set at the account level takes precedence.

Setting the charge order at the program level

At the program level, the charge order is set in program transaction types. When you use the Create program transaction type endpoint, set the charge order in the charge_order field.

You can also set the charge order using the Create transaction category endpoint. When the charge_order field is set in a transaction's transaction category, it overrides the charge order set in the transaction's program transaction type.

Setting the charge order at the account level

Alternatively, you can set the charge order at the account level. To do this, follow these steps.

1. Use the List account parameters endpoint to get the parameter ID for the SECONDARY_CHARGE_ORDER parameter.
2. Use this parameter ID with the Update account parameter endpoint to set SECONDARY_CHARGE_ORDER to a positive integer of your choice.
3. Create a new category using Create transaction category, and set the secondary_charge_order field to the charge order that you want to use when the SECONDARY_CHARGE_ORDER parameter is set.

If a transaction belongs to an account for which the SECONDARY_CHARGE_ORDER account parameter is set, the value of secondary_charge_order in the transaction category overrides the charge order defined in the program transaction type. (The charge_order parameter in the transaction category is also overridden.)