As we focus on hiring Software Engineer II with extensive payment experience, try your best to answer with the richest context possible. Can you describe a system you've worked on that involved processing financial transactions or moving money between accounts? If so, what project and context? What are the challenges? What solutions are proposed? How results are measured? (Using ChatGPT, CoPilot, DeekSeek or any supporting AI tools without context will not help much. Try to be original).✱