Staff Software Engineer, Backend, Money Team

Flex is a growth\-stage, NYC headquartered FinTech company that is creating the best rent payment experience. It's hard to believe that it's 2026 and paying rent on time is expensive, inflexible, and difficult. We're here to change that! Flex enables our users to pay rent throughout the month on a schedule that better fits their finances and budget. Our mission is to empower as many renters as possible with flexibility over their most significant recurring expense. After deliberately keeping a stealth profile as we built up unprecedented investor support and an enthusiastic user base, we are looking for motivated individuals to help us keep our mission growing. Will you be a part of the team? About The Role We are seeking a **Staff Software Engineer** to join our **Money Team**, responsible for building and scaling the financial infrastructure that powers payments, billing, subscriptions, payouts, ledgers, and other money movement systems across the company. As a Staff Engineer, you will provide technical leadership across multiple teams, drive the architecture of mission\-critical financial platforms, and help ensure our systems are secure, reliable, compliant, and scalable. You will partner closely with Product, Finance, Risk, Compliance, Data, and Engineering teams to deliver high\-impact solutions that directly affect revenue, customer experience, and business operations. What You'll Do * Design, build, and scale backend services and APIs that power Flex's core financial infrastructure, including payments, money movement, billing, settlements, reconciliation, and ledger systems. * Lead the architecture and evolution of highly available, fault\-tolerant financial platforms that process and track millions of dollars in transactions with accuracy, reliability, and auditability. * Provide technical leadership and guidance on distributed systems design, financial data consistency, transaction integrity, and long\-term platform strategy. * Drive the