They’re certainly not instantly cleared in the standard banking use of the term? I don’t doubt that you can reduce risk by e.g. using novel infrastructure whic

They’re certainly not instantly cleared in the standard banking use of the term? I don’t doubt that you can reduce risk by e.g. using novel infrastructure which looks up the account number on the check then uses (for example) a debit card network to check the account’s currently available balance. However, even if you were looking at someone’s balance on their mobile app while they were writing the check to you, that would not suffice to guarantee that the check would not be returned as NSF. The bank can choose to NSF it for a variety of reasons, for example if they prioritize “today’s” debit card transactions over “today’s” checks in the posting order, or a check previously deposited (and included in that available balance) gets NSFed and yanked back by another bank.