Unfortunately, Relay does not offer overdraft protection at this time. If a transaction attempt is made and your account does not have sufficient funds to cover the total amount of the transaction, the transaction will be returned.
While Relay does not offer traditional overdraft protection, you can set up a backup account for your debit card to serve as a secondary funding source. See How to Set Up a Backup Account for Your Debit Card.
We will never charge you a fee if a transaction is returned/cancelled due to insufficient funds.