CAREER SIM · Software Engineer

Step 1 of 4

A support ticket lands in your queue.

THE TICKET

SnapCart: e-commerce checkout, mid-flash-sale traffic. Your team: you + one on-call teammate. The challenge: customers charged twice for a single order, during peak traffic — on a checkout service + payment API with no request de-duplication. Your manager's message: "Sale traffic is only getting heavier. I need to know this is contained." Several customers say they were charged twice for the same order.

What's your first move?