Core banking systems are remarkably capable. But they were built in a different era—one where banks operated during the day and closed at night, much like a physical branch. That’s where "stand-in" systems come in. These systems temporarily take over transaction authorization while the Core is down.

The problem is, stand-in systems have real limits, as they open the door to a dangerous vulnerability.

Many institutions are rethinking the idea of switching back and forth between the Core and a stand-in. Instead of toggling between systems, many are implementing a real-time, always-on ledger—a Digital Twin.