This is similar to Square Cash, no?
The mechanism of paying people using their debit cards is the same.
Sort of like how gas stations have a higher price for credit card payments versus debit card payments.
It seems to me like you guys already have a system to map debit card numbers to bank accounts, so this should technically be possible as an ACH transfer. No?
That's not the way we're doing it. I've tried to find such a system, but AFAIK, it's not possible.