Is your system plagued by duplicate messages? We know the symptoms. When a single service begins to falter, the sickness spreads like wildfire. In the blink of an eye, your once-healthy system is coughing up duplicate messages everywhere. While flagellation might help, the traditional remedy prescribed by most doctors is the Outbox pattern. Unfortunately, the version your local healer recommends often comes straight from the Dark Ages. It may stop the duplicate coughing—but at a cost. Your precious database buckles under the immense burden of deduplication data, struggling to respond. It’s time to trebuchet your Outbox into the Renaissance. With the double-check deduplication pattern, your database is freed from the weight of outbox data, making system load predictable once more—and your architecture fit for a new age of enlightenment.