I speak as CTO of Paystack and I can assure you there is no evidence of this in our codebase. There is no evidence of same in either Uber’s or KongaPay’s codebase either.
Uber processes transactions directly through the MasterCard Internet Gateway Service with Access Bank as the acquiring bank.
KongaPay is a whole different ball game altogether, working with multiple banks and NIBSS to enable them directly debit bank accounts. You can confirm this with any developer on the KongaPay team. It is worthy of note that as at when the product launched, Flutterwave was not a thing.
That said, Paystack started off as Uber is - processing transactions via MiGS with Access Bank as our acquiring bank. It was why we could authorize and charge cards without requiring PINs or One Time Passwords. It was also the reason we could not process Verve cards at launch because those are local to Nigeria. Today, we work with multiple banks as acquirers, primarily GTB and Zenith, and directly with Interswitch to support PIN/Token authentication for MasterCard and Verve cards. For cards that have already been authorized once, we simply pass them off to MiGS for subsequent charges (recurring billing, or when a charge is sent to an existing customer’s card).
We also have relationships in place with eTranzact and NIBSS to make things like direct bank debits and automated transfers possible. As a player in the financial services space, we are also directly regulated by CBN as a Payment Service Provider and I can assure you that hasn’t been a small feat in terms of requirements - 100 million naira in share capital paid for, rate regulation, amongst other things. So no, you cannot just “become a retailer too if you are interested in fintech”.