In certain embodiments, a system for real-time overdraft detection includes one or more processors operable to: determine a deposit financial institution and deposit account based on the received check data, determine a debit financial institution and debit account based on the received check data, determine that the deposit financial institution and the debit financial institution are member financial institutions, determine a debit amount based on received check data, determine that the debit account matches an account associated with received account data, and determine that the debit amount exceeds an approved debit amount; the one or more interfaces further operable to communicate a declined transaction notification to the deposit account holder in response to determining that the debit amount exceeds the approved debit amount, the declined transaction notification notifying the deposit account holder that the debit amount cannot be credited to the deposit account holder.