NinjaTrader is a retail trading platform and futures broker focused on providing software and brokerage services for financial markets. The Staff Software Engineer will own the technical architecture of the Transaction Ledger and Treasury system within the cloud-native FCM platform, ensuring financial correctness, reconciliation integrity, auditability, and resilience. The role also establishes engineering standards, mentors engineers, guides modernization, and partners with leadership, compliance, product, and brokerage operations.