Senior Staff Infrastructure Engineer

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 Flex is looking for an exceptional Senior Staff Infrastructure Engineer with a passion for driving impact while managing high levels of ambiguity and Getting Stuff Done. In this role, you will be the bar raiser for the Infrastructure Engineering team, a small team responsible for creating and maintaining a sustainable set of platforms that ensures the effectiveness, reliability and scalability of our systems. You'll lead and enable the team in designing, building, and maintaining our robust and scalable infrastructure for engineers, customers, AI agents and fellow employees. You'll collaborate closely with our service engineering teams and leaders to determine the direction of our platform, and get ahead of where they need to be. At Flex, we are an AI-first engineering organization. We believe that the future of infrastructure isn't just about managing resources—it’s about building the intelligent, automated systems that manage them for us. We aren't looking for "task-takers"; we are looking for domain experts who use their deep knowledge of cloud architecture and SRE principles to steer these AI tools effectively. On this team, your value is defined by your ability to combine your technical mastery with an AI-augmented workflow to deliver world-class reliability at a growth-stage pace. We are particularly interested in candidates with software engineering experience in languages like Java, Python, or TypeScript. This background will allow you to collaborate effectively with product teams, build tools and automation, and improve the developer experience across our engineering organization. You’ll have the opportunity to influence key infrastructure and architecture decisions while ensuring high reliability and smooth delivery pipelines. This remote role requires a minimum of 10 years of cloud infrastructure experience. What you’ll do Define the long-term technical strategy for scalable and resilient infrastructure, guiding cross-functional teams to implement solutions that optimize for performance, resilience, and cost at an organizational level. Serve as the top technical authority ensuring the entire infrastructure platform aligns with critical business objectives and sets a high bar for industry standards. Own the end-to-end "build vs. buy" evaluation and decision process for all major infrastructure technology, weighing long-term cost, maintenance, scalability, and strategic business alignment. Serve as a hands-on technical authority, with the ability to dive deep into any part of the technology stack to diagnose complex systemic issues and drive best-in-class engineering solutions. Establish and evangelize a world-class SRE culture and practices across all engineering teams, defining SLOs/SLIs and leading initiatives to achieve target reliability goals for critical systems. Own and drive significant improvements in the end-to-end developer experience, including the architecture of self-service platforms, advanced CI/CD systems, and deployment mechanisms to maximize organizational velocity. Take command of major, high-severity incident responses that cross team boundaries, instituting structured post-incident review processes to extract systemic lessons and drive fundamental, long-term resilience improvemen ... (truncated, view full listing at source)