Your question is System Design for Banking Payloads. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Whiteboard an application-focused system design for a financial system such as a bank or payment system.
Asked in the onsite system design round stage. With a senior software engineer; followed by Q&A. Focus on how you would detect suspicious transactions in real time while keeping false positives low and meeting strict latency and compliance constraints.